Recycled fibers in reinforced concrete: A systematic literature review

Journal Pre-proof Recycled Fibers in Reinforced Concrete: a systematic literature review

Roberto Merli, Michele Preziosi, Alessia Acampora, Maria Claudia Lucchetti, Elisabetta Petrucci PII:

S0959-6526(19)34077-6

DOI:

https://doi.org/10.1016/j.jclepro.2019.119207

Reference:

JCLP 119207

To appear in:

Journal of Cleaner Production

Received Date:

01 February 2019

Accepted Date:

06 November 2019

Please cite this article as: Roberto Merli, Michele Preziosi, Alessia Acampora, Maria Claudia Lucchetti, Elisabetta Petrucci, Recycled Fibers in Reinforced Concrete: a systematic literature review, Journal of Cleaner Production (2019), https://doi.org/10.1016/j.jclepro.2019.119207

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.

Journal Pre-proof

Recycled Fibers in Reinforced Concrete: a systematic literature review Roberto Merli*1, Michele Preziosi1, Alessia Acampora1, Maria Claudia Lucchetti1, Elisabetta Petrucci2 1 Department

of Business Studies, Roma Tre University, Via Silvio D’Amico 77, 00145 Roma ITALY 2 Department of Chemical Materials Environmental Engineering, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Roma ITALY Email addresses: [email protected]*; [email protected]; [email protected]; [email protected]; [email protected]. Tel. contact: Roberto Merli - +39 3357107033

Journal Pre-proof Abstract Concrete is one of the leading composite materials for construction, therefore the identification of strategies aimed at reducing its environmental impact is crucial for greening the building industry and achieving the Sustainable Development Goals set by the United Nations. One way to reduce this impact involves the opportunity to recycle waste materials as fiber in concrete reinforcement, thus following the circular economy principles. The feasibility of using different waste materials in Recycled Fiber Reinforced Concrete (RFRC) is attracting practitioners’ attention. Through a systematic literature review, the paper analyzes the academic literature on concrete reinforcement using recycled fibers. The main goal is to provide an exhaustive analysis of the phenomenon with rigorous and reproducible research criteria. Eventually, 194 articles were analyzed. RFRC is a research topic, which is rapidly growing over the last years and scholars’ attention is focused both on engineering aspects, through experimental studies testing the composite mechanical properties, and environmental sustainability considerations. From the analysis, emerged that even though the relevance of the construction industry and, as a consequence, of concrete in the global transition toward sustainability it is widely recognized, there is a gap in investing the potential of RFCR in addressing the triple bottom line of it. Finally, it emerged a great research potential in exploring how recycled fibers may be part of a construction industry oriented and inspired to circular economy principles. Keywords: concrete; recycled fiber; fiber reinforced concrete; sustainability; circular economy

Summary 1. Introduction .........................................................................................................................2 2. Research methodology .........................................................................................................4 3. Material collection and category selection............................................................................5 4. Results..................................................................................................................................6 4.1 Distribution of times and sources...........................................................................................6 4.2 Type of research ....................................................................................................................7 4.3 Keywords families and network analysis...............................................................................7 4.4 Implications for sustainable development ............................................................................9 4.5 RFRC composites ..................................................................................................................9 4.6 Properties of RFRC ..............................................................................................................10 4.7 Materials of recycled fibers.................................................................................................11 4.7.1 Plastic fibers......................................................................................................................12 4.7.2 Metal fibers ......................................................................................................................16 4.7.3 Natural fibers ....................................................................................................................16 4.7.4 Others and Mixed .............................................................................................................21 4.7.5 Rubber fibers ....................................................................................................................21 4.7.6 Glass fibers .......................................................................................................................21 5. Discussion ………………………………………………………………………………………………………………………. 25 6. Conclusion ..........................................................................................................................26 References.................................................................................................................................26

Journal Pre-proof

1. Introduction One of the main challenges of the century is to embrace a sustainable development path, whose goal is to balance environmental, social and economic needs for present and future generations (Elkington, 1998). In this context, the civil construction industry is facing a crucial phase in order to meet the triple bottom line requirements of sustainability (Ding, 2008; Myers, 2005). Considering the environmental aspect, the construction industry accounts for half the consumption of raw materials and industrial waste, 40% of global energy consumption (Marinković et al., 2017), and between 40-50% of greenhouse gases (GHG) emissions (Khasreen et al., 2009; Petek Gursel et al., 2014). Additionally, the industry is responsible for other environmental impacts as the ecosystem degradation, contamination of soil, water and air (Vieira et al., 2016). Concrete is the most widely employed material in building construction and has a crucial role in providing health and a safe environment to the global population, being after water the most used resource (Henry and Kato, 2014). In fact, if properly produced, concrete has exceptional durability and mechanical characteristics, and is an excellent engineered material (Meyer, 2009). Currently, the world produces 4.4 billion tons of cement annually, but that number is expected to rise to over 5.5 billion tons by 2050, especially in developing countries (Lehne and Preston, 2018). As concrete is the most consumed building material, a strategy to reduce its impact on natural resource depletion and the environment is essential on a global level (Turk et al., 2015). Concrete negative impact mainly derives from cement production, which represents its main element. Cement alone is responsible for roughly 5-7% of CO2 anthropogenic global emissions, and 3% of global GHGs emissions (Van Den Heede and De Belie, 2012). Furthermore, the high consumption of mineral resources and fossil fuels, together with the large amount of waste generated, have to be included when considering the concrete environmental impact (Marinković et al., 2017). In order to find a balance between the industry growth and the structural limits of the planet and ensure the competitiveness of this construction material, it is crucial to develop strategies to mitigate concrete environmental impact and define new “green” concrete concepts (Van Den Heede and De Belie, 2012; Vieira et al., 2016). To do so, concrete industry will need to overcome the traditional linear path of production and consumption, to embody a circular approach considering the entire life cycle of its production chain (Ellen McArthur Foundation, 2013). Given the crucial role of the industry in terms of economic, social and environmental worldwide development, it may have a significant importance in achieving the Sustainable Development Goals (SDG) set by the United Nations (United Nations, 2015). Many of the 17 SDGs may be addressed in some way by the concrete supply chain when developing sustainable strategies for the industry. These strategies mainly aim at reducing raw materials consumption through the use of waste and recycled materials, the design of the structure with less material of high durability and the use of less impactful construction processes (Marinković et al., 2017). Concrete is a mixture of different components, among which Portland cement, fine and coarse aggregates, water and additives (Vieira et al., 2016). Traditional concrete has several weaknesses, mainly in terms of low tensile strength, low ductility, low energy absorption, low crack resistance, and shrinkage cracking (Kim et al., 2010; Wang et al., 2000; Zollo, 1997). In the last decades, to overcome these defects, the concrete mixture has started to be integrated with different types of fibers (Foti, 2013; Kim et al., 2010). This type of concrete is named Fiber Reinforced Concrete (FRC) and it can be defined as an amalgamated material constituted of Portland cement and aggregates, incorporating short isolated and irregular fibers (Sumathi and Saravana Raja Mohan, 2015). It is worth noting that, although the use of fibers in concrete is aimed mainly at improving the mechanical properties of the concrete products, minor applications include their use: 1) as a powder, for partial replacement of cement in order to limit costs, the release of hydration heat and the shrinkage phenomena associated with the use of this binder (S. Sharma and Singh, 2017; Sodhi and Salhotra, 2017); 2) as reinforcement for polymeric tubes used to confine recycled aggregate in concrete (Chen et al., 2016); 3) as link slabs in engineered cementitious composite materials, in concrete bridge deck (Kendall et al., 2008); 4) as repairing agent for ordinary Portland based concrete (Rebeiz et al., 1993). Fibers are often included in the formulation of lightweight concrete (Balaguru and Ramakrishnan, 1987), whose main properties are low density and high thermal insulation ability, and in selfcompacting concrete (SCC), whose main characteristic is the ability to achieve good compaction

Journal Pre-proof without external vibration. In this last case, rheological and mechanical synergistic effects of different fibers have also been verified (Nehdi and Ladanchuk, 2004). For structural use, high performance and ultra-high-performance concrete have been developed, in order to achieve high strength together with high toughness and durability. These highly performant products are obtained by optimization of both composition and mix design. To this aim, they often contain fly ash and silica fume as partial replacement of cement (Walraven, 2009). Fiber reinforced concretes have a wide range of applications. In particular, glass fibers are beneficial for precast panels, curtain wall facings, sewer pipes, thin concrete shell roofs, wall plaster and concrete blocks. Steel fibers are often included in roofs, pavements and floor slab, bridge decks, pipe, airport runways, pressure vessels, blast resistance structures, tunnel linings, while synthetic fibers are used for piles and facing panels. Other uses are construction of dams and wells, tunnel lining and slope stabilization. Synthetic conventional fibrous materials improve concrete performance, but they derive from nonrenewable and expensive natural resources. Additionally, they are not biodegradable and, once disposed, generate waste and negative environmental impact. Conversely, natural fibers are cheaper, cost-effective, renewable and therefore represent a sustainable source of fibers for FRC (Anandamurthy et al., 2017; Pacheco-Torgal and Jalali, 2011). The concrete industry, when using recycled fibers, may also contribute to reducing its environmental impact, waste streams and waste disposal in landfills. Scholars’ previous works have shown that various types of fibers recovered from different waste streams are suitable to produce reinforced concrete and are less costly than non-recycled fibers (Wang et al., 2000). This cascading use of waste for FRC production supports the “closing the loop” strategies for the implementation of circular economy practices (Merli et al., 2018). In fact, using by-products and waste as an input for concrete reinforcement would extend the value of resources, also contributing to the creation of new business opportunities (Ellen Macarthur Foundation, 2016). In the European context, the concrete industry has great potential in supporting the European Union circular economy goals. In the European strategy, besides improving resources efficiency, waste is to be considered as an alternative source of raw material (Turk et al., 2015). From this point of view, recycling and reuse of waste can be successfully adapted to the concrete industry, to generate an alternative supply of reinforcement fibers. While researchers’ attention is mainly focused on greening cement and aggregate materials, less attention is given to the potential use of fibers from recycled natural and synthetic materials (Anandamurthy et al., 2017). Considering the potential of using recycled fibers to contribute to transforming waste into valuable material, this study has as its main goal to review scholars’ contributions to the topic. However, in recent years, a growing number of scholars are investigating the potential of recycled waste materials in replacing traditional fibers for FRC production. This attention is due to a growing awareness around the environmental impact of the construction and building industry. Despite the significant amount of academic literature on the topic, a research gap has been identified with respect to classification and optimization of these precious materials. To fill this gap, the main goals of this work is to review researchers’ investigations on the topic. Therefore, the primary research question that arises is: What is the role of recycled fibers reinforced concrete (RFRC) and how scholars approach this topic? From these generic questions, we have developed a group of more specific ones:  How recycled fibers studies have evolved over time, sources and authors?  Which research methodologies are the most used to study RFRC?  How RFRC studies approach the triple bottom line of sustainability?  Which types of concrete are analyzed in selected literature?  Which recycled materials are employed in fiber reinforced concrete? Specific objectives of this paper are:  to provide an updated overview of all the recycled materials used as fibers in the concrete formulation. In fact, although some papers have analyzed specific categories of materials, there are no comprehensive reviews that collect them all  to evaluate the evolution over time and the spatial distribution of the interest in this topic, to understand whether for these issues we can foresee a steady development or only occasional attractiveness

Journal Pre-proof 

to determine whether the scientific interest is more focused on purely technical implications or if it involves also the environmental, social and economic benefits. A useful tool for this purpose is also represented by the analysis of the journals that publish these types of works  to explore for each type of analyzed fiber, the source from which it comes and the use for which it is intended After this introduction, Section 2 describes the research methodology. Section 3 explains material collection process; Section 4 describes the analytical categories employed and presents the evaluation of the results; Section 5 explores the different recycled fibers for concrete reinforcement analyzed by scholars; Section 6 provides discussion, implications and limitations of this study, proposing future lines of research; Section 7 presents the conclusion.

2. Research methodology This paper performed a systematic review of the literature on the topic of RFRC. The systematic literature review has been defined by Kitcharoen (2004) as a form of secondary study with the aim of “identifying, evaluating and interpreting all available research relevant to a particular research question, or topic area, or phenomenon of interest”. Our analysis integrates qualitative and quantitative evaluation being framed as content analysis (Brewerton and Millward, 2001). Following the guidelines of Denyer and Tranfield (2009) and Mayring (2003), the review process has been structured in five main five stages, which are explained below and in Figure 1:  Construction of research questions;  Material collection: material and unit of analysis identifications and definition;  Descriptive analysis: the collected material is evaluated and analyzed with quantitative methods;  Category selection: structural dimensions and related analytic categories are established to systematize the collected material;  Material evaluation: the systematized material is evaluated with respect to structural dimensions and related analytic categories;  Results are discussed to identify significant issues (Section 4; Section 5). The following sections define the methods and results employed during the review process, according to the five stages previously presented. Figure 1. Summary of the review process.

Journal Pre-proof

3. Material collection and category selection The material collection was carried out through Scopus. Scopus was employed for the research because it has been identified by Scholars as owning a high level of singularity (Sánchez et al., 2016) and as the database with the wider data coverage (Salim et al., 2019). The database, therefore, is one of the most inclusive and exhaustive scientific databases (Aghaei Chadegani et al., 2013), supporting the production process of a reliable bibliometric investigation. In order to capture green concrete studies across the scientific community, the following query has been formulated: TITLE-ABS-KEY ( concrete AND fiber OR fibre AND recycle OR recycling OR recycled OR by-product OR waste ) AND ( LIMIT-TO ( LANGUAGE , "English" ) ) AND ( EXCLUDE ( PUBYEAR , 2018 ) ) AND ( LIMIT-TO ( DOCTYPE , "ar" ) OR LIMIT-TO ( DOCTYPE , "re" ) OR LIMIT-TO ( DOCTYPE , "ip" ) ) AND ( LIMIT-TO ( SRCTYPE, "j" ) ) In the Scopus search, the research criteria were “Title, Author Keywords, Abstract”. The foundation of a review process is the delimitation of the unit of analysis. In this study, the single research or review article composes the unit. Thus, on database the results were limited to “Article”, “Article in press” and “Review”. Lastly, exclusively articles in English were chosen, as in the database English represents the most used language and it is also widely recognized as the international academic language. The research was performed on February 1, 2018. The research on Scopus returned 648 results. Next step was to critically evaluate these results in order to select those papers focusing on RFRC. In fact, from the analysis of query results, only those specifically dealing with recycled fibers in concrete reinforcement where further considered in the review. Starting from the 648 records initially extracted, we set aside 454 records that were not coherent with the scope of the research. Eventually, 194 records were employed to carry out the study. A concept-centric approach has been employed to structure the next part of this review (Webster and Watson, 2002). The structural dimensions and the analytical categories have been chosen (Mayring, 2003; Shukla and Jharkharia, 2013) considering the research questions proposed in the Introduction. Different structural dimensions were applied to analyze the topic. Next, for each of them, analytical categories were employed to evaluate the material. As a consequence, each unit of analysis may be part of different categories simultaneously. Therefore, the total count of articles may differ when considering the structural dimensions. Beginning with a deductive approach, categories have been retrieved from studies specifically investigating recycled materials for FRC, employing an iterative process. Finally, using an inductive process, those analytical categories that were not coherent with our analysis have been discarded and new ones identified (Mayring, 2003; Shukla and Jharkharia, 2013). In each following sub-section, the structural dimensions and related analytical categories are firstly listed, and then the results are presented.

4. Results 4.1 Distribution of times and sources The scientific interest for the usage of fibers from recycled materials is constantly growing over the last years. Figure 2 shows that from 1994 to 2008 studies on this specific topic did not exceed 5 papers per year. From 2009 figures started to grow, arriving at 25 papers published in 2016. However, 60

51

50 40 30 20

1998

1999

2000

2003

5

2

3

1

9

2012

1

9

2011

1

9

2010

2

8

2009

3

2006

2

2005

2

1997

10

1994

20

24 25

13

3 2017

2016

2015

2014

2013

2008

2007

2004

0

Journal Pre-proof the most significant increase was in 2017, in which 51 works were published, twice that of the past year (Figure 2). Figure 2. Evolution of published studies on recycled fibers in concrete per year. Considering the sources of these publications, twelve journals published more than three papers on the topic (Figure 3). Among them, the “International Journal of Civil Engineering and Technology” published 7 papers, the “Journal of Material in Civil Engineering” 8 papers, the “Journal of Cleaner Production” 11 papers. The most prolific journal with 43 papers is “Construction and Building Materials”, which main goal is the dissemination of research in the field of construction and building materials and their application in works and repair practice. When analyzing these sources, it is interesting to note that most of them have a very sectorial scope on engineering application of material for construction. Only two journals (“Waste Management” and the “Journal of Cleaner Production”) have a different focus related to environmental sustainability, testifying that recycled fibers in concrete are arising as an interesting topic that could support the transition toward a more environmental-friendly construction industry. Waste Management

3

Structural Concrete

3

Materials Research

3

Materials and Structures/Materiaux et Constructions

3

International Journal of Mechanical Engineering and Technology

3

Composites Part B: Engineering

3

Cement and Concrete Composites

3

Asian Journal of Civil Engineering

3 7

International Journal of Civil Engineering and Technology

8

Journal of Materials in Civil Engineering

11

Journal of Cleaner Production

43

Construction and Building Materials

0

5

10

15

20

25

30

35

40

45

50

Figure 3. Distribution among journal of papers about recycled fibers in concrete.

4.2 Type of research Results were analyzed according to the structural dimension “Type of research”. This dimension was adapted from the study of Lieder and Rashid (2016) who performed a literature review on the academic literature on circular economy. Types of research are divided into four analytical categories: Experimental study, Modelling, LCA, Review. Experimental studies refer to those works who mainly study, through experiments and tests, the mechanical and physical properties of RFRC. Modelling studies are those who develop statistical models to evaluate the potential behavior of the material in specific conditions. LCA studies are those applying the life cycle assessment to evaluate the environmental impact of RFRC. Finally, review studies are those that summarize previously published literature. As expected, considering the topic and the source journals, the vast majority of papers consist of Experimental studies (155), representing roughly 80% of the total (e.g. Hassani and Arjmandi, 2010; Martínez-Barrera et al., 2017; Torkaman et al., 2014). Works that jointly conducted an experimental study together with modeling (19) represent the second category. For example, Pereira et al. (2017) first conducted tests on concrete reinforced with recycled PET from bottles and then generate a mathematical model to predict its efficiency with specific operating parameters; while Medina et al. (2017) applied the same approach to study RFRC with recycled steel. Only 3 papers used modeling alone to study the use of steel fibers from tires waste (Groli and Caldentey, 2017; Jafarifar et al., 2017; Younis and Pilakoutas, 2013). LCA was employed in 3 studies, investigating the environmental impact of steel and PP fibers in pavements (Achilleos et al., 2011; Achilleos and Hadjimitsis, 2010) and footpaths (Yina et al., 2016). Thirteen review studies were identified. These studies mainly review the use of waste material for concrete fiber reinforcement. Many of them are focused on

Journal Pre-proof specific materials like plastics (e.g. Gu and Ozbakkaloglu, 2016; Jandiyal et al., 2016; Sharma and Bansal, 2016; Wang, 1999) or farming waste (e.g. Mo et al., 2016), while other generically investigate previous literature on recycled fibers (e.g. Wang et al., 2000). A single paper performed a significant review of literature on steel recycled fibers, followed by an experimental test (Vasudev and Vishnuram, 2014a). The preponderance of experimental studies seems to indicate that research is still at an early stage of technical assessment of the properties affected by the use of reinforced fibers and there is still little development in the direction of the feasibility and viability of these composite materials. Figure 4 summarizes the results for the structural dimension “Type of research”.

1

Review + Experimental study Modelling

3

LCA

3 13

Review

19

Experimental study + Modelling Experimental study

155 0

20

40

60

80

100

120

140

160

180

Figure 4. Type of researches on RFRC.

4.3 Keywords families and network analysis The next step of the analysis has been to evaluate the keywords employed by authors in the 194 papers selected, given that several keywords only differ in formal aspects (e.g. employing acronyms or a line), while others present significant conceptual similarities. To summarize and clarify the analysis, keyword families were developed (Figure 5). After “FRC” (43) and Concrete (34), many keywords families are associated with the properties of concrete: Compressive strength (30), mechanical properties (29), flexural strength (21), ductility (12) and split tensile strength (10). Three categories are associated with the type of recycled material as steel fiber (10), waste tire (10) and PET (10). Another important keywords family is related to recycling (19). 50 45 40 35

43 34 30

30

29 21

25 20

19 12

15

10

10

10

10

10 5 0 Fiber reinforced concrete Mechanical properties Ductility Waste tire

Figure 5. Keywords families

Concrete Flexural strength PET Split tensile strength

Compressive strength Recycling Recycled steel fiber

Journal Pre-proof Next, with the help of the VOSviewer software (version 1.6.5), a map based on bibliographic data we have performed a Co-occurrence analysis of keywords). This free software, developed at Leiden University by Nees Jan van Eck and Ludo Waltman (van Eck and Waltman, 2010), allows making maps to visualize bibliometric network data based on the visualization of similarities (VOS) technique (Wong, 2018). Co-occurrence analysis studies the relatedness of keywords considering the number of publications in which they occur together. Author keywords were used as a unit of analysis with the full counting method. To create a clear and representative map of the network we required a minimum of three occurrences for each keyword. Eventually, 48 keywords have met the threshold. The main keywords are FRC (36 occurrences) and concrete (33). Figure 6 presents the most employed keyword and the link strength in terms of their co-occurrences. Among the other keywords found more than 10 times we have compressive strength (26), mechanical properties (24), flexural strength (15) and recycling (13). Among the eight identified clusters, the strongest relationships in terms of keywords co-occurrences are among “concrete” and “compressive strength”, “concrete” and “mechanical properties”, and “concrete” and “recycling”.

Figure 6. Authors’ keywords for RFRC network analysis with at least 3 occurrences.

4.4 Implications for sustainable development Building and construction industry are among the most critical for reaching a more sustainable society. Given the size of the industry and the importance of concrete for its operations, it is crucial to identify new paths for reducing its impact in terms of economic, environmental and social sustainability. Academics can contribute to this goal investigating strategies to make concrete production more sustainable. In relation to this aspect, we proceeded to examine the records considering the triple bottom line of sustainability. The analytical categories were retrieved from CSR and sustainable supply chain review studies (Goyal et al., 2013; Seuring and Müller, 2008), and adjusted for our analysis. The goal was to categorize the selected articles considering their economic, environmental or social focus. Given the technical and engineering focus of studies dealing with RFRC, another category was added (technical). The goal was to better understand if scholars investigate the use of recycled material from not only a technical perspective, but also considering the triple bottom line of sustainability. Figure 7 shows that the majority of papers have only a technical point of view on the usage of recycled fibers (47.2%), studying the technical properties of the composite material (e.g. Al-Tikrite and Hadi, 2017; Mastali et al., 2017). The technical aspects are studied jointly with considerations on environmental sustainability in almost 40% of the cases. It demonstrates a growing awareness of scholar for the potential of recycled material in concrete production, especially considering the potential of reducing waste disposed of in landfills (e.g. Mohammadhosseini et al., 2017; Schmidt and Cieślak, 2008) and reducing the withdrawal of overexploited raw materials (e.g. Ozger et al., 2013).

Journal Pre-proof In 14 papers the analysis was further expanded with economical aspects (e.g. Achilleos et al., 2011; Meyer, 2004), while only technical and economic considerations were studied in 7 papers (e.g. Coatanlem et al., 2006; Groli and Caldentey, 2017). Figure 7 also highlights that only in one paper technical considerations of concrete properties were not considered, preferring to analyze its environmental impact with LCA (Yina et al., 2016). Finally, to be noted, that the social implications of RFRC were considered in one study (Yuzer et al., 2013).

SOC

0

ECO

0

ENV

1

TEC+ENV+SOC

1 7

TEC+ECO

14

TEC+ENV+ECO

79

TEC+ENV

92

TEC 0

20

40

60

80

100

Figure 7. Dimensions of sustainable development explored.

4.5 RFRC composites In the section, we have analyzed if in studies dealing with recycled fibers in concrete, other components such as fine and coarse aggregates and cement were also examined (Figure 8). The analysis showed that 138 studies focused only on the recycled fiber (e.g. Ahmad et al., 2010; Jandiyal et al., 2016). Additionally,19 papers analyzed recycled fiber and recycled aggregate (e.g. Aziz et al., 2017; Cheng et al., 2017). Sharma and Singh (2017) analyzed the influence on the various strength of concrete by the addition of coconut fibers and replacing fine aggregates in concrete by steel slag. Others articles, instead, focused on recycled fibers and recycled cement (17) (e.g. Akhtar and Ahmad, 2009; Lejano and Gagan, 2017). For example, Awal and Mohammadhosseini (2016) evaluated the performance of concrete incorporating waste carpet fiber (WCF) and palm oil fuel ash (POFA) as partial replacements of ordinary Portland cement (OPC). Additionally, 11 studies tested the performance of concrete with both recycled fiber and conventional fibers (e.g. Ozerkan et al., 2016; Yina et al., 2016). In four studies the focus is on recycled fibers, aggregates and cement (e.g. Hama, 2017; Kharbuki and Malik, 2017) and in three on the joint application of recycled fibers and non-recycled cement (e.g. Dar and Salhotra, 2017; Kurup and Senthil Kumar, 2017a). Only one paper concerns the application in concrete of recycled fibers and non-recycled aggregates (e.g. Belferrag et al., 2016), whilst another investigates recycled fibers and cement with conventional aggregates (e.g. Ciocan et al., 2017).

Journal Pre-proof 160 140

138

120 100 80 60 40 19

20

17

11

4

3

1

1

0 RF

RF+RA

RF+RC

RF + NRF RF+RA+RC RF+NRC

RF+NRA FR+NRA+RC

Figure 8. RFRC composites Legend: RF= recycled fibres; RA=recycled aggregates; RC=recycled cement; NRF=non-recycled fibres; NRC=non-recycled cement; NRA= non-recycled aggregates.

4.6 Properties of RFRC Literature has shown that fibers for concrete reinforcement may enhance its properties. The presence of fibers improves the concrete performances, by increasing toughness, ductility and resistance to impact while reducing its weight and density, and, therefore, by improving the high strength-to-weight ratio (Anandamurthy et al., 2017; Foti, 2013; Wang et al., 2000). Particularly, fibers control cracking due to both plastic and drying shrinkage. The presence of fibers in concrete does not affect the occurrence of cracks, but succeeds in delaying their propagation (Islam and Das Gupta, 2016). The addition of fibers also reduces the permeability of concrete thus positively affecting its durability (Islam and Das Gupta, 2016) and reducing bleeding phenomena. Depending on fibers shape and dimensions, it is also possible to obtain improved freeze-thaw resistance (Berkowski and Kosior-Kazberuk, 2015). Finally, enhancement in fire resistance has been observed (Mahasneh, 2005). Major drawbacks of fibers addition in the concrete formulation are the possibility of reducing workability (Mello et al., 2014) and the higher costs associated either to fibers, if not deriving from waste or scrap recovery, or to superplasticizers requirements. In function of the potential application, a great variety of fibers and their combination are employed to produce FRC. Fibers can be of natural (animal, mineral and cellulose/lignocellulose), or synthetic origin (organic and inorganic) (Jawaid and Abdul Khalil, 2011). Among these, steel, glass, natural cellulose, carbon, nylon, polypropylene are the most used (Wang et al., 2000). However, it is crucial to ensure that recycled fibers are suitable for maintaining and improving concrete performances. Scholars investigating how to replace conventional fibers with recycled fibers have to test the resulting concrete properties. Therefore, the need to green the industry must go hand in hand with the analysis of RFRC to meet recognized quality standards. Figure 9 summarized the main properties of concrete tested into the selected literature. Mechanical properties in general are the most investigated (450 times), followed by Durability (31), Fresh concrete properties (23), Physical (22) and Composites (11). Additionally, thermal (10) and Fracture (3) properties were marginally analyzed.

Journal Pre-proof 500

450

450 400 350 300 250 200 150 100

37

50

31

23

Durability

Fresh contrete

22

11

10

3

0 Mechanical Other

Physical Composites Thermal

Fracture

Figure 9. RFRC properties analyzed by scholars. Given the relevance attributed to mechanical properties, Figure 10 highlights those that have been tested more than 10 times. The four most analyzed are Compressive Strength (96), Flexural Strength (75), Tensile Strength (68) and Cracks (40). Modulus of Elasticity and Shrinkage have been tested 24 times each, while Toughness (21), Ductility (19), and Impact Resistance (11) are less explored. 120 96

100

75

80

68

60 40 40

24

24

21

19

20

11

e

ct

re sis

ta

nc

ity ct il Du

Im pa

ug

hn

es s

e To

ka g

st el a of

M od

ul

us

Sh rin

ty ici

ks ac Cr

re ng th

ns

ile

st

tre ng Te

ls ra xu

Fle

Co

m pr es

siv e

st

re ng th

th

0

Figure 10. Mechanical properties analyzed in more than 10 papers.

4.7 Materials of recycled fibers Figure 11 shows the materials’ categories that have been more studied by authors for producing RFRC. In the next sub-sections, most analyzed materials for each category are described, together with the recovered commodity source of the material and, when applicable, the destination commodity for concrete usage.

Journal Pre-proof 80 70

69

60 48

50 40

28

30

21

20

14 8

10

6

0 Plastic

Metals

Naturals

Others

Mixed

Rubber

Glass

Figure 11. Main materials used for recycled fibers.

4.7.1 Plastic fibers Plastic fibers derive from a wide range of synthetic polymers including PET (polyethylene terephthalate), PE (polyethylene), PP (polypropylene), nylon, polyester and many others. Depending on their size, they are grouped in microfibers (with a diameter of 5-100 µm and 5-30 mm long) and macro fibers (cross section of 0.6–1 mm2 and 30–60 mm long) (Yin et al., 2015). The inclusion of microfibers into concrete tends to reduce its plastic shrinkage, with slight benefit on mechanical properties (Pelisser et al., 2010), apart from toughness. On the other hand, macro fibers provide the additional advantage of avoiding drying shrinkage (Pujadas et al., 2014), while improving the postcracking response. Polymeric materials have generally high costs. In addition, their production implies complex processes as the source material is oil and, therefore, their use for construction purposes is of poor feasibility. On the contrary, the use of recycled plastics, especially from waste bottles, is of great environmental interest as it finds a green application to a steadily increasing class of waste, known for its low or null biodegradability. Plastics recovered from waste are the most studied recycled fibers to reinforce concrete, analyzed in 69 papers. Of these, 43 analyze different types of reinforced concrete. For example, Recycled PET Fiber Reinforced Concrete (e.g. Fraternali et al., 2011) and Nylon Fiber Reinforced Concrete (e.g. Ozger et al., 2013). 12 papers do not specify the type of concrete (e.g. Mohammadhosseini et al., 2017; Sodhi and Salhotra, 2017), 4 discuss Self Compacting Concrete (e.g. Al-Hadithi and Hilal, 2016), 3 about Light-weight Concrete (e.g. Sadrmomtazi et al., 2012). Considering the specific plastic material, almost half of the papers (28) deal with PET (Polyethylene terephthalate) (e.g. Foti, 2013; Vishnu et al., 2017). The other two most studied plastic materials are PP (polypropylene) (13) (e.g. Yin et al., 2016) and HDPE (High-density polyethylene) (3) (e.g. Pešić et al., 2016). Considering the commodity from which the plastic was recovered, plastic bottles from municipal waste is the most employed with 24 papers (e.g. Pereira et al., 2017), followed by textile industry (10). In the textile sector, carpets are often used as a source of recycled material (e.g. Abdul Awal, 2015; Mohammadhosseini et al., 2017a). Additionally, 3 studies analyze the potential of bag manufacturing (e.g. Ghernouti et al., 2015) and domestic plastic waste (e.g. Kandasamy and Murugesan, 2014). Even though not often specified by authors, applications may serve for pavements (e.g. Ochi et al., 2007) and other construction applications.

1 2

Table 1 – Plastic fibers

Title (Yazdanbakhsh et al., 2017) (Pereira et al., 2017)

Concrete Type Fiber reinforced polymer (FRP) Concrete

Building commodity / destination

Fiber type

Recycling Source

Needles from bar scraps

—

PET

PET bottles

Fiber reinforced concrete —

COMPARISON

Sustainability Aspects

—

Tech Tech / Env Tech / Env / Eco

(Mohammadhosseini et al., 2017a)

FRC

PP carpets

Textile

—

(Kurup and Kumar, 2017a)

FRC

PVC cable

Electronic

—

— Carpet fiber with ordinary Portland cement (OPC) concrete Normal concrete

Plastic Fiber Reinforced Concrete (PFRC)

PET

Bottles

—

—

Tech / Env

(Sodhi and Salhotra, 2017)

Concrete

Plastic

—

—

—

Tech / Env / Eco

(Dar and Salhotra, 2017)

Concrete

PET

Bottles

—

Light weight aggregate concrete

Plastic

Bottles

—

FRC

Outer casing insulation of wire

Electronic

—

Normal concrete

Tech / Env

(Karanth et al., 2017)

Waste plastic fiber reinforced concrete

Plastic

Doors

—

—

Tech

(Cheng et al., 2017)

Lightweight wet-mix shotcrete

PET; PP (not specified if recycled)

Agriculture / bottles

Roadway support as lightweight shotcrete

Plain concrete (PC)

Tech / Env

Concrete

PP carpet

Textile/agricult ure

—

Without palm oil fuel ash (POFA) with ordinary Portland.

Tech / Env

Concrete

PP carpet

Textile / agriculture

—

With and without POFA

Tech / Env

FRC

Plastic

—

—

Conventional concrete

Tech / Env

Ring-shaped PET (RPET) fiber in concrete

PET

Bottles

—

RPET

Tech / Env

(Rinu Isah and Shruthi, 2017)

FRC

PET

Bottles

—

Ordinary concrete, steel reinforced concrete

Tech

(Al-Hadithi and Hilal, 2016)

SCC

Waste plastic fibers (WPF)

Cutting beverage bottles

—

—

Tech

(Pešić et al., 2016)

FRC

Simply extruded recycled HDPE

—

—

—

Tech / Env

(Vishnu et al., 2017)

(Hama, 2017) (Kurup and Kumar, 2017b)

(Mohammadhosseini et al., 2017b) (Mohammadhosseini and Yatim, 2017) (Dinesh and Hanumantha Rao, 2017) (Khalid et al., 2017)

Natural coarse aggregate concrete Reference mix without plastic fibers

Tech / Env

Tech / Env Tech / Env

(Yin et al., 2016)

FRC

PP

—

(Vijaya et al., 2016) (Foti, 2016) (Gu and Ozbakkaloglu, 2016) (Borg et al., 2016) (Sharma and Bansal, 2016)

SCC FRC

Plastic PET

— —

Footpaths, precast panels — —

Concrete

Plastic

—

FRC Concrete

PET Waste plastic

Neat asphalt concrete mixture Sand concrete

(Usman et al., 2016) (Guendouz et al., 2016) (Choudhary and Aggarwal, 2016) (Jandiyal et al., 2016) (Yin et al., 2015a) (Otuoze et al., 2015) (Ghernouti et al., 2015) (Khaloo et al., 2015) (Abdul Awal et al., 2015)

—

Tech

— —

Tech Tech

—

—

Tech / Env

Bottles —

— —

— —

Tech Tech / Env

PET

—

Asphalt concrete

—

Tech / Env

PET; LDPE

Bags manufacture

Sand concrete

—

Tech

Polypropylene fiber reinforced fly ash concrete FRC

PP

Various

—

—

Tech / Env

PET

Bottles

—

Tech

FRC

PP

Industrial waste

—

Asphalt concrete SCC High performance concrete (HPC) FRC

PP Plastic

Pavement — —

—

Tech

PP carpet

— Plastic bags Discarded car timing belts Waste carpet

— Recycled vs. Non recycled — — —

Tech

—

Tech

—

Tech

Polymer fibers

Tech Tech Tech

(Yin et al., 2015b)

FRC

PP processed

—

(Nibudey et al., 2015) (Karthikeyan and Vennila, 2015)

FRC

PET

Bottles

— Concrete footpaths —

FRC

PET

Bottles

—

—

Tech

(Subramaniaprasad et al., 2015)

Stabilized mud masonry blocks

Plastic

Mineral water bottles, carry bags

Soil masonry blocks

Raw specimen

Tech

Recycled polyethylene terephthalate fiber-reinforced concrete (RPETFRC)

PET

—

—

—

Tech

Hybrid Fiber Reinforced Concrete (HYFRC) beams

Scrim bled steel (Non recycled); recycled PET and PP

—

—

—

Tech

Recycled PET fiber-reinforced concretes

PET

—

—

—

Tech

(Kandasamy and Murugesan, 2014)

FRC

Domestic waste plastic

Domestic waste plastic

—

—

Tech / Env

(Koo et al., 2014)

Hwangtoh concrete mixed with short recycled PET fibers

PET

PET bottles

—

Tech / Env

(Prem Kumar et al., 2014)

FRC

PE

Polyethylene waste

—

Tech

(Foti and Paparella, 2014)

FRC

PET

PET bottles

—

Tech / Env

Concrete

PET

Plastic bottles

—

Tech / Env

(Fraternali et al., 2014) (Karthik and Maruthachalam, 2014) (Spadea et al., 2014)

(Machovič et al., 2013)

Construction applications Construction applications Road; airport pavements —

(Foti, 2013) (Ozger et al., 2013) (Sadrmomtazi et al., 2012) (Pelisser et al., 2012) (Bhavi et al., 2012) (Kandasamy and Murugesan, 2012) (Dai et al., 2011) (Foti, 2011) (Kandasamy and Murugesan, 2011)

FRC

PET

Bottles

Nylon

Carpet

Propylene PET HDPE

— Bottles —

Polythene

Domestic waste plastic

PEN; PET PET Polythene

— Thermal energy storage — — —

—

Tech / Env

Traditional concrete

Tech / Env

— — —

Tech Tech / Env Tech / Env

—

—

Tech / Env

PET bottles

—

—

Tech

PET bottles Domestic waste plastic

—

—

Tech / Env

—

—

Tech

PET

PET bottles

—

—

Tech

(Dhariwal, 2010)

Recycled PET fiber-reinforced concrete (RPETFRC). FRC

Plastic

—

—

Tech / Env

(Kim et al., 2010)

Structural concrete

PET

PET bottles

—

Expanded polystyrene (EPS) concrete

Polyamide 66 waste fibers Glass fiber reinforced plastic (GRP) waste

Carpet

—

— PP fiber reinforced concrete Non-reinforced EPS concrete

—

—

—

Tech / Env

(Fraternali et al., 2011)

(Haghi and Beglou, 2009) (Asokan et al., 2009) (Alhozaimy and Shannag, 2009)

Concrete

Tech / Env Tech / Env

FRC

LDPE

Plastic bottles

—

Plain concrete

Tech / Env

Asphalt

Roofing polyester waste fibers

Building roofing

Hot mix asphalt

—

Tech / Env / Eco

Concrete reinforced by poly (ethylene terephthalate) fibers

PET

Bottles

—

—

Tech

(Schmidt and Cieślak, 2008)

Fibers reinforced concrete

Polyamide (PA); PP

Carpet

—

—

Tech / Env

(Ochi et al., 2007)

Fiber reinforced concrete

PET

PET bottles

Gateway support; pavements

—

Tech

(Ogi et al., 2005)

Carbon fiber reinforced plastic reinforced concrete

Recycled and crushed carbon fiber reinforced plastic

—

—

—

Tech

(Lee et al., 2005)

Fiber-Reinforced Asphalt Concrete

Nylon

Carpet

—

—

Tech

Generic concrete

Nylon

Carpet

—

—

FRC

Commingled plastics

—

—

Portland cement concrete

HDPE

—

—

— Virgin polypropylene fibers

(Anurag et al., 2009) (Machoviè et al., 2008)

(Meyer, 2004) (Stier and Weede, 1998) (Auchey, 1998)

3

RFRC Nylon fibre-reinforced concrete Lightweight concrete RFRC FRC Fiber Reinforced Self Compacting Concrete (FRSCC) Fiber reinforced polymer (FRP) FRC

Tech / Env / Eco Tech / Env Tech / Eco

Journal Pre-proof 4

4.7.2 Metal fibers

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Metal fibers are for the vast majority represented by steel. Steel fibers, commercially available in different shapes and sizes, are the most commonly used type of fibers either alone or in combination with rubber or polymers. Today, the replacement of raw steel fibers with recycled fibers deriving essentially from waste tires is frequently proposed. Steel fibers confer to concrete ductility and resistance to fatigue, impact, blast and abrasion. In addition, they limit cracks width. The achievement of beneficial effect requires addition of approximately 1-2% by volume. Major drawbacks are a reduction in workability, which often requires a plasticizer addition, if added in concentration higher than 0.5% (Mello et al., 2014), and the susceptibility to corrosion, especially in chloride-rich marine environment with possible loss of mechanical and aesthetic properties, if not well embedded in the paste (Mangat and Gurusamy, 1988). In 58 cases, recovered metals have been analyzed as fibers in the papers. Mainly the family of Reinforced concretes (32) has been investigated (e.g. Centonze et al., 2012). Among the others we can remind Self-compacting Concrete (3) (e.g. Mastali and Dalvand, 2017, 2016), Light-Weight (1) (e.g. Aghaee and Yazdi, 2014) and Two-stage Concrete (1) (e.g. Nehdi et al., 2017). The vast majority (43) analyze the steel (e.g. Al-Tikrite and Hadi, 2017; Caggiano et al., 2017; Graeff et al., 2012). Other 4 refer to generic metal waste fibers (e.g. Belferrag et al., 2016) and 1 to brass (e.g. Zubaidi et al., 2013). When taking into consideration the product source, 28 papers describe metal recovered from tires (e.g. Ismail et al., 2017; Sengul, 2016) in the automotive industry. In some cases, the material is recovered from lathe shops (e.g. Vasudev and Vishnuram, 2014), turnery (e.g. Sarabi et al., 2017) and metal drilling (e.g. Hassani and Arjmandi, 2010). Applications for recycled metal fiber reinforced concrete are mainly pavements (e.g. Jafarifar et al., 2016), for example used in airports pavements (e.g. Cojocaru et al., 2013). Another frequent application refers to beams (e.g. Zamanzadeh et al., 2015).

28

4.7.3 Natural fibers

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

For the reinforcement of building materials, the choice can be also extended to fibers of natural origin, of which the clay and straw brick, used since ancient times, represents a well-known example. In particular, among the articles it has been reported the use of vegetal materials (such as coir or sisal or wood fibers), of animal materials (such as pig and even human hair) and also of mineral materials (essentially basalt or asbestos). Natural fibers mainly derive from renewable sources. One of the main advantages is that they are generally low cost, of easy provision, and environmentally friendly, especially considered that recycled natural fibers are agro-food byproducts or residues. So far, conflicting data have been inferred from their mechanical characterization. Construction materials reinforced with natural fibers often exhibit performances lower than synthetic and metal fibers, and in some cases comparable to those of glass (Al-Oraimi and Seibi, 1995). In particular, natural fibers seem to impair the durability of the final product. However, recent studies have shown that the fibers pretreatment can improve their performance and make them appealing for the sustainable building market (Sivaraja et al., 2010). Natural fibers, which have been studied in 28 papers, group together vegetable and animal recycled fibers. Apart from FRC, some authors tested their application in Light-weight Concrete (5) (e.g. Younis and Pilakoutas, 2013) and Self-Compacting Concrete (2) (e.g. Mohamed et al., 2010). Among vegetable fibers (20), those from coconut (5) (e.g. Othuman Mydin et al., 2015; Sharma and Singh, 2017), oil palm (e.g. Ahmad et al., 2010; Aziz et al., 2017) and bagasse (e.g. Khushnood et al., 2015) residues have been widely analyzed. Other sources are hemp (e.g. Schwarzova et al., 2017), wool (e.g. Coatanlem et al., 2006) and rice husk (e.g. Sivaraja and Kandasamy, 2010). With respect to animal fibers (7), different materials have been tested such as human (e.g. Manivel et al., 2017) and pig hair (e.g. Lejano and Gagan, 2017), and chicken feathers (e.g. Hamoush and Carolina, 1994).

53

Table 2 – Metal fibers Title

Concrete Type

Fiber type

Recycling Source

Building commodity / destination

COMPARISON

Sustainability Aspects

Comparison among industrial micro steel fiber (MF), industrial deformed steel fiber (DF) and waste steel fiber.

Tech

(Al-Tikrite and Hadi, 2017)

RPC reactive powder concrete

Steel

Tires

Reactive powder concrete (RPC)

(Sarabi et al., 2017)

Concrete for massive structures

Steel

Turnery

Massive structures

RC

Steel

Tires

—

Two-Stage Concrete

Steel

Tires

Pavement, sidewalks

RC

Steel

Tires

—

(Rashid and Balouch, 2017)

FRC

Steel

Tires

—

(Ahmadi et al., 2017)

FRC

Steel

Tires, demolition

Pavement

Steel

Tires

—

Steel Machined steel parts waste

Tires —

Steel

(Caggiano et al., 2017) (Nehdi et al., 2017) (Domski et al., 2017)

(Baricevic et al., 2017) (Mastali and Dalvand, 2017b) (Atlaoui and Bouafia, 2017) (Jafarifar et al., 2017) (Groli and Caldentey, 2017) (Ismail et al., 2017) (Mastali and Dalvand, 2016a) (Sengul, 2016) (Leone et al., 2016) (Jafarifar et al., 2016) (Belferrag et al., 2016)

Sustainable hybrid fiber reinforced concrete (SHFRC) SCC FRC Steel fibers reinforced conventional rollercompacted concrete. Concrete Concrete containing fly ash SCC FRC RSFRC Roller compacted concrete Fiber reinforced sand concrete

Tech / Eco Concrete reinforced with industrial steel

Tech / Env Tech / Env / Eco

Concrete with engineered steel fibers Conventional concrete Steel fibers concrete with natural aggregate

Tech / Env

Concrete with manufactured steel fibers

Tech / Env

Concrete with PP fibers

Tech

Beam

Concrete 0% fibers

Tech

Tires

—

Conventional roller-compacted concrete.

Tech

Steel

Tires

—

—

Tech / Eco

Steel

Tires

—

—

Tech / Env

Steel Steel Steel

— Scrap tires Waste tires

— — —

— — —

Tech Tech Tech

Steel

Tires

Pavements

—

Tech

Pneumatic waste metal fibers

Tires

—

—

Tech

Tech

Tech / Env

(Groli et al., 2015)

FRC

Steel

Tires

Columns

—

Tech

(Martinelli et al., 2015)

FRC

Steel

Tires

—

—

Tech

(Foglar et al., 2015)

FRC

—

—

—

Tech

FRC RSFRC

Steel (recycled); polypropylene (nonrecycled) Steel Steel

Tires Tires

— Beams

Tech Tech

(Aghaee et al., 2015)

FRC

Steel

Used formworks

— — Mixed waste steel wires, mixed steel fibers, plain concrete

(Jafarifar et al., 2014)

Concrete pavements

Steel

Tires

—

Tech

(Groli et al., 2014)

SCC Structural lightweight concrete (SLWC) FRC FRC FRC

Rebars; steel

Tires

Pavements, ground restrained slabs —

—

Waste steel wires

Constructions

—

—

Steel Steel Steel

Lathe shop Waste Lathe shops Rehabilitation of road and airport pavements

Beams — —

Steel FRC vs ordinary concrete — —

Tech / Env Tech / Env / Eco Tech / Env Tech Tech / Env

Airport pavements

—

Tech

(Caggiano et al., 2015) (Zamanzadeh et al., 2015)

(Aghaee and Yazdi, 2014) (Vasudev and Vishnuram, 2014) (Kakvand et al., 2014) (Vasudev and Vishnuram, 2014a) (Cojocaru et al., 2013) (Younis and Pilakoutas, 2013) (Sotoudeh and Jalal, 2013) (Belferrag et al., 2013) (Zubaidi et al., 2013) (Jalal, 2012) (Graeff et al., 2012) (Kalpokaite-Dickuviene et al., 2012)

Tech

Roller compacted concrete

Steel

Recycled aggregate concrete

Steel

Tires

—

—

Tech

SFRC

Steel

Slivers from industrial waste

—

—

Tech

Reinforced sand dune concrete (MFSC) Concrete

Steel

Tires

—

Traditional concrete

Tech / Env

Brass

—

—

Tech / Env

RSFRC

Steel

—

Fibers from tires

Tech / Env

FRC

Steel Industrial waste catalyst

By-product brass Milling and machining process Tires Industrial waste catalyst

Pavement

FRC traditional

Tech / Env

Refractory concrete

—

Tech

(Centonze et al., 2012)

RFRC

Steel

Tires

—

Industrial fiber reinforced concrete

Tech / Env

(Achilleos et al., 2011)

SFRC

Steel tire-cord wire

—

Pavement

—

Tech / Env / Eco

(Neocleous et al., 2011) (Abbas, 2011) (Achilleos and Hadjimitsis, 2010) (Hassani and Arjmandi, 2010) (Aiello et al., 2009) (Tlemat et al., 2006) (Sekar, 2004) (Keyvani and Saeki, 1997)

54 55

Steel-fibre-reinforced roller-compacted concrete SFRC

Steel

—

Pavements

—

Tech / Env

Steel

Industrial waste

—

—

FRC

Steel

Tires

Pavement

—

Tech / Env Tech / Env / Eco

Conventional and silica fume concrete RSFRC SFRC

Waste metal drillings Steel Steel

Pavement slabs

Steel fibers

Tech

— —

— —

Tech / Env Tech

FRC

Lathe; wire winding; wire drawing

—

—

Tech / Eco

SFRC

Steel shavings or chips

Waste metal drilling Tires Tires Wire winding and wire drawing industries Steel forming workshops

—

—

Tech

Table 3 – Natural fibers Concrete Type

Fiber type

Recycling Source

Building commodity / destination

FRC

Cellulose

Algae waste

—

(Sharma and Singh, 2017) (Sharma and Singh, 2017a) (Kharbuki and Malik, 2017)

Concrete FRC Concrete

Food/steel plant Food —

— — —

(Anandamurthy et al., 2017)

FRC

Coconut coir Coconut coir Coconut coir Bioscraps not specified

Agriculture

—

Title (Cengiz et al., 2017)

(James et al., 2017)

Concrete

Hair

Human

—

(Manivel et al., 2017)

FRC

Hair

—

(Aziz et al., 2017)

FRC

Oil palm fruit fiber

Human Oil palm extraction, agrifood industry

(Schwarzova et al., 2017)

Lightweight composites

Hemp

Paper industries, textile industries

(Lejano and Gagan, 2017)

FRC

Pig-hair

—

— Hemp concrete, fiber boards and lightweight composites Low load structures, beams and columns

COMPARISON Commercial cellulose concrete — — Control md25

Sustainability Aspects Tech / Env Tech / Env Tech / Env Tech / Env Tech / Env

Different but not specified

Tech / Env Tech

—

Tech / Env

—

Tech

—

Tech

(Fathi and Fathi, 2016) (Othuman Mydin et al., 2015) (Khushnood et al., 2015) (Bdour et al., 2015)

Foamed concrete

Tragacanth gum; sugar beet fiber Coconut coir

Cement composites

Bagasse

Hot asphalt mixes (HMA)

Wire wool

Concrete

Food industry plants

—

—

Tech / Env

Agricultural waste Waste bagasse fibers (particles) By-product wire wool industry, home waste

—

—

Tech / Env

—

—

Tech

Asphalt concrete mixes

—

Tech

(Meena and Elangovan, 2014)

Fiber Reinforced Self compacting concrete

(Ruben and Baskar, 2014)

Concrete composites

AR glass fibers; Carbon fiber; Recron 3s fibers and human hair (a waste material fiber) fibers Waste coir fiber

(Torkaman et al., 2014)

Lightweight concrete

Wood fiber waste

—

—

—

Textile

Textile

—

—

Tech / Env Tec / Env / Soc

(Aghaee and Foroughi, 2013) (Yuzer et al., 2013) (Jarabo et al., 2012) (Ahmad et al., 2011) (Sivaraja and Kandasamy, 2010) (Ahmad et al., 2010) (Mohamed et al., 2010) (Akhtar and Ahmad, 2009) (Reis, 2006) (Coatanlem et al., 2006) (Hamoush et al., 1994)

—

—

—

Tech / Eco

Coir

—

—

Tech / Env Tech / Env / Eco

Cubic lightweight concrete Fiber Reinforced Self Compacting Concrete (FRSCC) FRC FRC FRC FRC Self-compacting concrete

Raw rice husk

Paddy rice

—

—

Hemp Human hair Rice husk Oil palm trunk fiber Micro vegetable fibers

Cooking process Food industry Oil palm industry

— — — —

Tech / Env Tech / Env Tech Tech

Recycled paperboard

—

— — — — Equivalent mortar (cement)

Concrete

Hair

Humans

—

—

Tech / Env

Natural fiber-reinforced polymer concrete

Coconut; sugar cane bagasse; and banana fibers

Agricultural waste

—

Synthetic fibers

Tech

Wood chippings

—

Buildings

—

Tech / Eco

Chicken feathers

Food production

—

—

Tech / Env / Eco

Wood fiber lightweight concrete Feather fiber reinforced concrete

Tech / Env

Journal Pre-proof 57

4.7.4 Others and Mixed

58 59 60 61 62 63 64 65 66 67 68 69

The analytical category “Others” groups together those materials that were not possible to specifically insert in a single category. It is composed of 21 papers analyzing different sources of materials. Of these, in three cases Self-Compacting Concrete was reinforced with recycled Carbon Fiber Reinforced Polymer (e.g. Mastali and Dalvand, 2016b; Murali and Chandana, 2017). Fibers from textile industry have been analyzed in 9 paper, mainly employing fibers from carpets (e.g. (A. S. M. A. Awal and Mohammadhosseini, 2016; Wang et al., 2000). In one case, post-consumer clothing has been used as a fiber source. Cellulosic fibers from Tetrapak packaging (e.g. Kumar and Prakash, 2016) and newspapers (e.g. Martínez-Barrera et al., 2017) were also tested. Shifting to the Mixed category, this gathers papers (14) in which two or more recycled fibers have been analyzed jointly or the applications of different types of fiber have been tested. Among them, 7 studies analyzed jointly plastics and metals fibers (e.g. Ozerkan et al., 2016; Thirumurugan and Sivaraja, 2015), while others mix together with other materials.

70

4.7.5 Rubber fibers

71 72 73 74 75 76 77 78 79 80 81

Rubbers in shape of powder, crumbs or fibers, always from a recycled source, typically waste tires, can be added to concrete to obtain the so-called rubberized concretes (Sofi, 2017). Rubber provides concretes with high ductility and toughness. However, because of the weak bond between cement and rubber particles, these materials exhibit low compressive strength (Xue and Shinozuka, 2013). For this reason, it is preferentially applied to meet the requirements of shock resistance, for example in case of seismic events, and sound insulation, for roadways in non-load bearing structures, in lightweight concrete walls, building facades, roofing tiles and road traffic barriers. Recent research has highlighted the possibility of increasing the mechanical properties of materials by combination with silica fume or by acting on rubber content and also by its pre-treatment with sodium hydroxide (Li et al., 2016). Rubber fibers have been tested in 8 cases, mainly recovering the material from tires (e.g. Flores Medina et al., 2016; Serdar et al., 2015).

82

4.7.6 Glass fibers

83 84 85 86 87 88 89 90 91 92 93 94 95 96

Glass fibers, normally added at a high-dosage amount, are often used in reinforced materials especially where improved hardness or decorative value are required for example for countertops and facades. For a long time, the use of glass in building materials has been limited by its susceptibility to the alkaline conditions provided by cement that result in its embrittlement and finally in reduced strength and durability. Today, due to the development of alkali-resistant glass fibers together with the use of mortar additives, the use of glass fibers in construction has been steadily increasing. Recycled glass fibers for reinforced concrete mostly derives from waste glass fiber reinforced polymers (GFRPs). They are more often used as a cement replacement, due to their pozzolanic potential, or as aggregate, but some detrimental effects on the resulting strength have been highlighted (Shi and Zheng, 2007). Considering the review results, recycled glass fibers have been analyzed in 6 papers. In some cases, waste glass reinforced polymers are added to concrete (e.g. Dehghan et al., 2017; Mastali et al., 2016). Yang et al. (2010) investigated recycled municipal solid waste incinerator ashes to produce a Man-Made Vitreous fiber from plasma vitrified slug.

97 98 99

Table 4 - Various fibers

Title (Martínez-Barrera et al., 2017) (Bhogayata and Arora, 2017) (Mastali et al., 2017) (Liu et al., 2017) (Murali and Chandana, 2017) (Rhee et al., 2017) (Mastali and Dalvand, 2016b) (Awal and Mohammadhosseini, 2016) (Kumar and Prakash, 2016) (Malaiškiene et al., 2015)

Fiber type

Recycling Source

Building commodity / destination

COMPARISO N

Sustainability Aspects

Polymer concrete

Cellulose

Tetra Pak packaging

Polymer concrete

—

Tech / Env

Food packaging

—

—

Tech / Env

— Textile

— Foamed concrete

— —

Tech Tech / Env

SCC Foamed concrete

Metalized plastic waste MPW CFRP Textile

SCC

CFRP

—

—

—

Tech

Concrete

Pitch based carbon

Refinery

Slabs, piers

—

Tech

SCC

CFRP

—

—

—

Tech

FRC

Carpet

Textiles

—

—

Tech / Env

Paper concrete

Paper

Newspaper

—

—

Tech / Env

Concrete

Waste tire cord yarn

Tires

—

—

Tech

(Ucar and Wang, 2011)

Lightweight cementitious composites

Carpet

Carpet

—

Tech / Env

(dos Reis, 2009) (Artemenko et al., 2008) (Naik et al., 2004) (Wang et al., 2000)

FRC Polymer-asphalt-concrete Cellucrete FRC

Textile trimming waste Basalt fiber or wool Pulp and paper mills Various waste

Textile — — —

Underlayment and wall panels for buildings or outdoor structures — Pavement — —

— — — —

FRC

Carpet

Carpet

—

—

Tech / Env Tech Tech Tech / Env Tech / Env / Eco

Textile manufacturer

—

—

Tech / Eco

—

— Construction applications; highway, bridge; airports

—

Tech

—

Tech / Env

(Wang, 1999)

FRC

(Wang, 1998)

FRC

Postconsumer fibers used clothing Various

(Wang, 1997)

FRC

Carpet

Carpet

(Wang et al., 1994)

FRC

Carpet industrial waste

Carpet

—

Virgin polypropylene fibers

Tech

(Parameswaran, 1991)

FRC

Organic and inorganic

—

Building components

—

Tech / Env / Eco

(Chang et al., 1999)

100

Concrete Type

Generic concrete

101 102

Table 5 - Mixed fibers

Concrete Type

Fiber type

Recycling Source

Building commodity / destination

COMPARISON

Sustain ability Aspects

(Medina et al., 2017)

FRC

Steel; rubberized plastic

Tires

—

Conventional rubberized concrete

Tech

(Girardi et al., 2017)

FRC

Polyamide fibers from post-consumer textile carpet waste; metallic powders or shavings and steel fibers

—

Thermal storage units for solar plants

Ordinary concrete

Tech

Self-consolidating concrete (SCC) reinforced

Micro-steel; HDPE

Municipal wastes

—

Unreinforced concrete

Tech

Concrete

Bamboo; corn; wheat; olive; sisal; seashells

Farming

—

—

Tech / Env

Concrete footpaths

Steel reinforcing mesh; virgin PP fiber; recycling industrial PP waste; Recycling domestic PP waste

Industrial, domestic

Concrete footpath

—

Env

Steel; nylon

Steel lathe

—

—

Tech

Polyester; glass

Thermoset composite

—

—

Tech Tech / Env Tech / Env / Eco Tech / Env / Eco Tech / Env

Title

(Ozerkan et al., 2016) (Mo et al., 2016) (Yina et al., 2016) (Thirumurugan and Sivaraja, 2015) (Sebaibi et al., 2014)

High-strength concrete reinforced Waste Fiber and Powder Reinforced Concrete (WFPRC)

(Flores-Medina et al., 2014)

Dry consistency concretes

Steel; textiles

Tires

—

Reference concrete

(Serdar et al., 2014)

Generic concrete

Steel; textiles

Tires

—

—

—

—

—

—

—

—

Tech

(Bjegovic et al., 2013) (Thirumurugan and Sivaraja, 2013)

Rubberized hybrid fiber reinforced concrete (RHFRC) Hybrid fiber reinforced concrete

(Sivaraja et al., 2010) (Meddah and Bencheikh, 2009) (Soroushian et al., 2003)

103 104 105

Mechanical recycling of waste tires Steel lathe waste; nylon waste Waste rural materials

Rubber; steel Steel; nylon

FRC

Nylon; plastic; tire

FRC

F waste metallic fibers (wmf); polypropylene fibers (wpf)

—

—

—

Tech / Env

FRC

Plastic and papers

—

—

Recycled vs virgin

Tech

Table 6 - Rubber fibers

Title

Concrete Type

Fiber type

Recycling Source

Building commodity / destination

COMPARISON

Sustainability Aspects

— Tires

— —

Only rubber ash 0% rubber fibers

Tech Tech / Env

Tires

—

—

Tech

Concrete FRC Concrete

Rubber Rubber Fibers partially coated with crumb rubber (FCR) Rubber Polymer (tire) Crumb rubber

— Tires Tires

— — —

— PP fibers —

Tech Tech Tech / Env

(Li et al., 2004b)

Waste tire modified concrete

Rubber; PP (not recycled)

Waste tires

—

—

Tech

(Li et al., 2004a)

Waste tire fiber modified concrete

Rubber

Waste tire

—

—

Tech

(Gupta et al., 2017b) (Gupta et al., 2017a) (N Flores Medina et al., 2016) (Gupta et al., 2015) (Serdar et al., 2015) (Grinys et al., 2013)

106 107 108

Rubberized concrete Rubberized concrete Rubberized concrete

Table 7 - Glass fibers

Title

Concrete Type

Fiber type

Recycling Source

Building commodity / destination

Compariso n

Sustainability Aspects

(Dehghan et al., 2017)

Concrete

Waste glass fiber reinforced polymers (GFRPs)

Waste glass fiber reinforced polymers (GFRPs)

Concrete, mortar beam and prism tests

—

Tech

(Ciocan et al., 2017)

Epoxy polymer concrete with fly ash

Glass

—

—

—

Tech

(Mastali et al., 2016)

SCC

—

—

—

Tech

(Barbuta et al., 2015)

Cement concrete Waste Fiber and Powder Reinforced Concrete (WFPRC)

Glass Fiber Reinforced Polymers (GFRP) Glass

—

—

—

Tech

Polyester; glass

Thermoset composite

—

—

Tech

Micro-concrete

Glass

—

Precast microconcrete components

—

Tech

FRC

Man-made vitreous fiber (MMVF) from plasma vitrified slag; municipal solid waste incinerator ashes

Municipal solid waste incinerator ashes

—

—

Tech

(Sebaibi et al., 2014) (García et al., 2014) (Yang et al., 2010)

Journal Pre-proof 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165

5. Discussion With a systematic approach, the paper outlined results of a literature review targeted to academic studies investigating the use of recycled materials as fibers in the production of FRC. From Scopus, an initial dataset of 648 records has been extracted. Following the research questions formulated, 194 papers were selected for the analysis and distributed across the identified structural dimensions. Results show that the use of recycled fibers in concrete reinforcement is a research topic that is gaining growing attention between practitioners from 2009, especially in sectorial journals focused on the analysis of FRC technical properties. Even though technical performances of concrete remain as the protagonist in the analyzed literature, some authors underline the implications of recycled fibers in reducing the amount of waste into landfill and preserving scarce raw materials. For this reason, journals with a strong environmental scope, as the Journal of Cleaner Production and Waste Management, carved a widening niche in RFRC studies. This reflects the fact that scholars are starting to give relevance also to the potential impact of recycled fibers in contributing to making the concrete industry more sensitive to environmental issues. Nevertheless, not much attention has been given to the economic and social potentialities of using these materials for concrete production. The vast majority of the analyzed articles adopted the experimental study approach, mostly investigating the mechanical properties of concrete reinforcement with recycled fibers. Given the composite nature of FRC, the research has highlighted that often the use of recycled materials is studied not only for fiber reinforcement, but also jointly with aggregates and cement obtained from the same matrixes, opening the way for greening the entire composition of concrete. From the analysis of the keywords it emerged that the properties of concrete are the most discussed aspect in recycled FRC. Mechanical properties are the most tested or investigated by scholars. Among them, compressive, flexural and tensile strength have the pride of place. However, also durability and fresh concrete properties are taken into consideration. The next step of the analysis has been the research of the different type of materials used as recycled fibers for concrete reinforcement. Plastic fibers emerged as the most tested, followed by steel and naturals fibers. Even if less studied, glass and rubber fibers were also tested. The most explored recycled material inside the plastic fibers category is Polyethylene terephthalate (PET), which is widely used in manufacturing beverage packaging. PET bottles, after being disposed of, are landfilled or incinerated, leading to serious environmental problems. In this sense, the use of recycled PET as fiber reinforcement in concrete is a possible solution to overcome waste management issues (Kim et al., 2010). Major applications of recycled fibers in FRC come from the reuse of scrap tires. This type of waste not only causes serious environmental impact but the disposal of tires in regular landfills is often prohibited. The most common disposal method of old tires seems to be to burn them to produce steam and electricity or heat. However, steel fiber and rubber from end-of-life tires can be reused in concrete production. Steel fibers can be used as reinforcement in concrete and rubber particles can be employed as a partial or total replacement of natural aggregates for obtaining ‘‘rubberized concrete”. Additionally, recycled polymer fibers obtained from end-of-life tires can be used as reinforcement in concrete. A great contribution to reducing resources input and enhancing sustainability in concrete production also comes from the agricultural or agri-food sector. These sectors can greatly contribute to greening the concrete industry, representing a great source of raw materials or by-products for FRC, contributing to improving its properties. At the same time, the reuse of these materials reduces waste disposal and, as a consequence, their impact on the environment. Results show scholars’ great interest in investigating different natural fibers in FRC. Among these, the coir (coconut fiber) has created great interest in researchers for its excellent physical and mechanical properties and its abundant availability in tropical regions. Additionally, glass fiber in concrete studies mainly refers to Waste Glass Fiber Reinforced Polymer (GFRP) that recently has been discovered to be reusable in FRC partially recovering its fibers. Even if waste GFRP presents the shortcomings of waste plastic aggregates, it has the positive implications of fibers and powdered waste glass (Dehghan et al., 2017). Concluding, it has to be also mentioned the potential applications of textile fibers, especially from carpets, which fibers are recovered both from pre and post-consumer waste (Mohammadhosseini et al., 2017a). Mainly due to its qualitative approach, the study has some limitations. Despite the review process has been clearly documented through a systematic approach to information classification,

Journal Pre-proof 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219

researchers’ bias may have affected results. It should also be considered that the review has been conducted exclusively with the Scopus dataset and not considering papers included in other indexed journals. However, this choice ensures a reliable quality of the collected data. Additionally, it has to be considered that, to match the length of the paper required by the journal, for each analytical category not all the papers have been cited. However, significant and representative examples have been mentioned. Finally, research is biased by the specific research criteria (the string in the Scopus research box) that have been chosen, inevitably excluding potentially relevant material. Limitations of the study represent an opportunity to improve future investigation in this research area. Looking at the boundaries of the review, forthcoming research may integrate together with academic literature also grey literature, that it is often a source of significant knowledge. The analysis has shown that the opportunity to employ recycled material into concrete it is not limited to fibers, but it is applied also to the other concrete’s components. Due to synthesis needs, the review did not explore in detail scholars’ findings in relation to each recycled material (e.g. plastic, metals, natural materials, rubber and glass) tested as fiber. Researchers may study in further details the implications of using these materials. Additionally, a similar review process may be performed analyzing the potentiality of using waste materials for replacing concrete’s aggregates and cement. Further investigation would be a stimulus for improving knowledge on the use of recycled materials in concrete and, more in general, for the introduction of green initiatives in the construction and building industry. The study has shown that almost exclusively environmental related issued of sustainability have been considered in the analyzed literature. Analyzing the results it emerges that little attention has been given to the economic and social aspects of sustainability, as the vast majority of papers has taken into account only the environmental aspects. A larger effort is required to evaluate the impact of recycled fibers on the triple bottom line of sustainability. Studies on the usage of recycled fibers in concrete mainly have a technical approach (experimental studies). Nevertheless, besides concrete properties characterization, scholars will have to reflect on the market implications. Among these, the availability of recycled fibers on the market, the need to consolidate the use of these materials overcoming traditional supply chains, and establishing new marketplaces for “green” concrete production. Bearing this goal in mind, the industry may benefit from the application of industrial ecology practices, establishing opportunities for closed loops cycles of materials (Watkins et al., 2010). Among these practices, the material flow system thinking of industrial symbiosis could facilitate the creation of networks in which by-products fibers can be easily accessible.

6. Conclusions How do scholars deal with the RFRC? The paper has presented the findings of a literature review realized to respond this question. The scope of the investigation was to present an overview of recycled materials used as fibers in the concrete formulation and to explore how the academic world approach to this topic. The paper has provided the identification of a framework to categorize the literature, through the analysis of nearly 200 articles published in journals retrieved from Scopus. This framework is composed of structural dimensions and analytical categories, which allowed to analyze the main trends of the research on the topic. Results have shown that the academic interest on RFRC is growing sharply over the last years and that the topic is mainly approached through experimental studies testing the composite mechanical properties. The analysis has provided a specific focus on recycled materials used in reinforced concrete, indicating plastic and metals as the most studied fibers. From the analysis, it also emerged that even though the relevance of the construction industry and, as a consequence, of concrete in the global transition toward sustainability it is widely recognized, there is a gap in investing the potential of RFCR in addressing the triple bottom line of it. Finally, it emerged a great research potential in exploring how recycled fibers may be part of a construction industry oriented and inspired to circular economy principles.

References Abbas, A.H., 2011. Management of steel solid waste generated from lathes as fiber reinforced concrete. Eur. J. Sci. Res. 50, 481–485. Abdul Awal, A.S.M., Mohammadhosseini, H., Hossain, M.Z., 2015. Strength, modulus of elasticity

Journal Pre-proof 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276

and shrinkage behaviour of concrete containing waste carpet fiber. Int. J. GEOMATE 9, 1441–1446. Achilleos, C, Hadjimitsis, D.G., 2010. Comparison of conventional and “ECO” transportation pavements in cyprus using life cycle approach. World Acad. Sci. Eng. Technol. 66, 379–383. Achilleos, C., Hadjimitsis, D., Neocleous, K., Pilakoutas, K., Neophytou, P.O., Kallis, S., 2011. Proportioning of steel fibre reinforced concrete mixes for pavement construction and their impact on environment and cost. Sustainability 3, 965–983. doi:10.3390/su3070965 Aghaee, K., Foroughi, M., 2013. Mechanical properties of lightweight concrete partition with a core of textile waste. Adv. Civ. Eng. 2013. doi:10.1155/2013/482310 Aghaee, K., Yazdi, M.A., 2014. Waste steel wires modified structural lightweight concrete. Mater. Res. 17, 958–966. doi:10.1590/1516-1439.257413 Aghaee, K., Yazdi, M.A., Tsavdaridis, K.D., 2015. Investigation into the mechanical properties of structural lightweight concrete reinforced with waste steel wires. Mag. Concr. Res. 67, 197– 205. doi:10.1680/macr.14.00232 Aghaei Chadegani, A., Salehi, H., Md Yunus, M.M., Farhadi, H., Fooladi, M., Farhadi, M., Ale Ebrahim, N., 2013. A comparison between two main academic literature collections: Web of science and scopus databases. Asian Soc. Sci. 9, 18–26. doi:10.5539/ass.v9n5p18 Ahmad, S., Ghani, F., Hasan, M., 2011. Use of waste human hair as fibre reinforcement in concrete. J. Inst. Eng. Civ. Eng. Div. 91, 43–49. Ahmad, Z., Saman, H.M., Tahir, P.M., 2010. Oil palm trunk fiber as a bio-waste resource for concrete reinforcement. Int. J. Mech. Mater. Eng. 5, 199–207. Ahmadi, M., Farzin, S., Hassani, A., Motamedi, M., 2017. Mechanical properties of the concrete containing recycled fibers and aggregates. Constr. Build. Mater. 144, 392–398. doi:10.1016/j.conbuildmat.2017.03.215 Aiello, M.A., Leuzzi, F., Centonze, G., Maffezzoli, A., 2009. Use of steel fibres recovered from waste tyres as reinforcement in concrete: Pull-out behaviour, compressive and flexural strength. Waste Manag. 29, 1960–1970. doi:10.1016/j.wasman.2008.12.002 Akhtar, J.N., Ahmad, S., 2009. The effect of randomly oriented hair fiber on mechanical properties of fly-ash based hollow block for low height masonry structures. Asian J. Civ. Eng. 10, 221– 228. Al-Hadithi, A I, Hilal, N.N., 2016. The possibility of enhancing some properties of self-compacting concrete by adding waste plastic fibers. J. Build. Eng. 8, 20–28. doi:10.1016/j.jobe.2016.06.011 Al-Oraimi, S.K., Seibi, A.C., 1995. Mechanical characterisation and impact behaviour of concrete reinforced with natural fibres. Compos. Struct. 32, 165–171. doi:10.1016/0263-8223(95)000437 Al-Tikrite, A., Hadi, M.N.S., 2017. Mechanical properties of reactive powder concrete containing industrial and waste steel fibres at different ratios under compression. Constr. Build. Mater. 154, 1024–1034. doi:10.1016/j.conbuildmat.2017.08.024 Alhozaimy, A.M., Shannag, M.J., 2009. Performance of concretes reinforced with recycled plastic fibres. Mag. Concr. Res. 61, 293–298. doi:10.1680/macr.2008.00053 Anandamurthy, A., Guna, V., Ilangovan, M., Reddy, N., 2017. A review of fibrous reinforcements of concrete. J. Reinf. Plast. Compos. 36, 519–552. doi:10.1177/0731684416685168 Anurag, K., Xiao, F., Amirkhanian, S.N., 2009. Laboratory investigation of indirect tensile strength using roofing polyester waste fibers in hot mix asphalt. Constr. Build. Mater. 23, 2035–2040. doi:10.1016/j.conbuildmat.2008.08.018 Artemenko, S.E., Arzamastsev, S. V, Shatunov, D.A., Vyazenkov, A.A., 2008. Basalt plastics - New materials for road construction. Fibre Chem. 40, 499–502. doi:10.1007/s10692-009-9094-1 Asokan, P., Osmani, M., Price, A.D.F., 2009. Assessing the recycling potential of glass fibre reinforced plastic waste in concrete and cement composites. J. Clean. Prod. 17, 821–829. doi:10.1016/j.jclepro.2008.12.004 Atlaoui, D., Bouafia, Y., 2017. Experimental characterization of concrete beams elements reinforced by long fiber chips. J. Adhes. Sci. Technol. 31, 844–857. doi:10.1080/01694243.2016.1233620 Auchey, F.L., 1998. The use of recycled polymer fibers as secondary reinforcement in concrete structures. J. Constr. Educ. 3, 131–140. Awal, A.S.M.A., Mohammadhosseini, H., 2016. Green concrete production incorporating waste carpet fiber and palm oil fuel ash. J. Clean. Prod. 137, 157–166. doi:10.1016/j.jclepro.2016.06.162 Aziz, F.N.A.A., Sani, M.B., Noor Azline, M.N., Jaafar, M.S., 2017. A comparative study of the

Journal Pre-proof 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333

behaviour of treated and untreated tyre crumb mortar with oil palm fruit fibre addition. Pertanika J. Sci. Technol. 25, 101–120. Balaguru, P., Ramakrishnan, V., 1987. Properties of Lightweight Fiber Reinforced Concrete. Spec. Publ. 105. doi:10.14359/2180 Barbuta, M., Marin, E., Cimpeanu, S.M., Paraschiv, G., Lepadatu, D., Bucur, R.D., 2015. Statistical analysis of the tensile strength of coal fly ash concrete with fibers using central composite design. Adv. Mater. Sci. Eng. 2015. doi:10.1155/2015/486232 Baricevic, A., Bjegovic, D., Skazlic, M., 2017. Hybrid fiber-reinforced concrete with unsorted recycled-tire steel fibers. J. Mater. Civ. Eng. 29. doi:10.1061/(ASCE)MT.1943-5533.0001906 Bdour, A.N., Khalayleh, Y., Al-Omari, A.A., 2015. Assessing mechanical properties of hot mix asphalt with wire wool fibers. Adv. Civ. Eng. 2015. doi:10.1155/2015/795903 Belferrag, A., Kriker, A., Khenfer, M.E., 2013. Improvement of the compressive strength of mortar in the arid climates by valorization of dune sand and pneumatic waste metal fibers. Constr. Build. Mater. 40, 847–853. doi:10.1016/j.conbuildmat.2012.11.079 Belferrag, A., Kriker, A., Abboudi, S., Bi, S.T., 2016. Effect of granulometric correction of dune sand and pneumatic waste metal fibers on shrinkage of concrete in arid climates. J. Clean. Prod. 112, 3048–3056. doi:10.1016/j.jclepro.2015.11.007 Berkowski, P., Kosior-Kazberuk, M., 2015. Effect of fiber on the concrete resistance to surface scaling due to cyclic freezing and thawing. Procedia Eng. 111, 121–127. doi:10.1016/j.proeng.2015.07.065 Bhavi, B.I.K., Reddy, V. V, Ullagaddi, P.B., 2012. Effect of different percentages of waste High Density Polyethylene (HDPE) fibres on the properties of fibre reinforced concrete. Nat. Environ. Pollut. Technol. 11, 461–468. Bhogayata, A.C., Arora, N.K., 2017. Fresh and strength properties of concrete reinforced with metalized plastic waste fibers. Constr. Build. Mater. 146, 455–463. doi:10.1016/j.conbuildmat.2017.04.095 Bjegovic, D., Baricevic, A., Lakusic, S., Damjanovic, D., Duvnjak, I., 2013. Positive interaction of industrial and recycled steel fibres in fibre reinforced concrete. J. Civ. Eng. Manag. 19, S50– S60. doi:10.3846/13923730.2013.802710 Borg, R.P., Baldacchino, O., Ferrara, L., 2016. Early age performance and mechanical characteristics of recycled PET fibre reinforced concrete. Constr. Build. Mater. 108, 29–47. doi:10.1016/j.conbuildmat.2016.01.029 Brewerton, P.M., Millward, L.J., 2001. Organizational research methods: A guide for students and researchers. SAGE Pubblications. Caggiano, A., Xargay, H., Folino, P., Martinelli, E., 2015. Experimental and numerical characterization of the bond behavior of steel fibers recovered from waste tires embedded in cementitious matrices. Cem. Concr. Compos. 62, 146–155. doi:10.1016/j.cemconcomp.2015.04.015 Caggiano, A., Folino, P., Lima, C., Martinelli, E., Pepe, M., 2017. On the mechanical response of Hybrid Fiber Reinforced Concrete with Recycled and Industrial Steel Fibers. Constr. Build. Mater. 147, 286–295. doi:10.1016/j.conbuildmat.2017.04.160 Cengiz, A., Kaya, M., Pekel Bayramgil, N., 2017. Flexural stress enhancement of concrete by incorporation of algal cellulose nanofibers. Constr. Build. Mater. 149, 289–295. doi:10.1016/j.conbuildmat.2017.05.104 Centonze, G., Leone, M., Aiello, M.A., 2012. Steel fibers from waste tires as reinforcement in concrete: A mechanical characterization. Constr. Build. Mater. 36, 46–57. doi:10.1016/j.conbuildmat.2012.04.088 Chang, Y., Chen, H.-L., Francis, S., 1999. Market applications for recycled postconsumer fibers. Fam. Consum. Sci. Res. J. 27, 320–340. doi:10.1177/1077727X9902700303 Chen, G.M., He, Y.H., Jiang, T., Lin, C.J., 2016. Behavior of CFRP-confined recycled aggregate concrete under axial compression. Constr. Build. Mater. 111, 85–97. doi:10.1016/j.conbuildmat.2016.01.054 Cheng, W, Liu, G., Chen, L., 2017. Pet fiber reinforced wet-mix shotcrete with walnut shell as replaced aggregate. Appl. Sci. 7. doi:10.3390/app7040345 Choudhary, M.C., Aggarwal, V.R., 2016. Polypropylene fiber reinforced fly ash concrete - A literature review. Int. J. Earth Sci. Eng. 9, 2016–2025. Ciocan, V, Şerbănoiu, A.A., Drăgoi, E.-N., Curteanu, S., Burlacu, A., 2017. Optimization of glass

Journal Pre-proof 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390

fibers used as disperse reinforcement of epoxy polymer concrete with fly ash. Environ. Eng. Manag. J. 16, 1115–1121. Coatanlem, P., Jauberthie, R., Rendell, F., 2006. Lightweight wood chipping concrete durability. Constr. Build. Mater. 20, 776–781. doi:10.1016/j.conbuildmat.2005.01.057 Cojocaru, R, Andrei, R., Muscalu, M., Ţǎranu, N., Budescu, M., Lungu, I., 2013. The behavior of cement concrete made with recycled materials for airport rigid pavements . Rev. Rom. Mater. Rom. J. Mater. 43, 363–372. Dai, J.-G., Bai, Y.-L., Teng, J.G., 2011. Behavior and modeling of concrete confined with FRP composites of large deformability. J. Compos. Constr. 15, 963–973. doi:10.1061/(ASCE)CC.1943-5614.0000230 Dar, U.N., Salhotra, S., 2017. Effect of metakaolin and plastic bottles on durability of concrete: Experimental work. Int. J. Civ. Eng. Technol. 8, 830–835. Dehghan, A, Peterson, K., Shvarzman, A., 2017. Recycled glass fiber reinforced polymer additions to Portland cement concrete. Constr. Build. Mater. 146, 238–250. doi:10.1016/j.conbuildmat.2017.04.011 Denyer, D., Tranfield, D., 2009. Producing a Systematic Review, in: The SAGE Handbook of Organizational Research Methods. pp. 671–689. doi:10.1080/03634528709378635 Dhariwal, A., 2010. Laboratory investigations on environmental pollutant materials : Plastics and flyash. Indian J. Environ. Prot. 30, 943–947. Dinesh, Y., Hanumantha Rao, C., 2017. Strength characteristics of fibre reinforced concrete using recycled PET. Int. J. Civ. Eng. Technol. 8, 92–99. Ding, G.K.C., 2008. Sustainable construction-The role of environmental assessment tools. J. Environ. Manage. 86, 451–464. doi:10.1016/j.jenvman.2006.12.025 Domski, J., Katzer, J., Zakrzewski, M., Ponikiewski, T., 2017. Comparison of the mechanical characteristics of engineered and waste steel fiber used as reinforcement for concrete. J. Clean. Prod. 158, 18–28. doi:10.1016/j.jclepro.2017.04.165 dos Reis, J.M.L., 2009. Effect of textile waste on the mechanical properties of polymer concrete. Mater. Res. 12, 63–67. Elkington, J., 1998. Partnerships from cannibals with forks: The triple bottom line of 21st-century business. Environ. Qual. Manag. 8, 37–51. doi:10.1002/tqem.3310080106 Ellen MacArthur Foundation, 2013. Towards the Circular Economy. Economic and Business Rationale for an Accelerated Transition. Ellen Macarthur Foundation, 2016. THE CIRCULAR ECONOMY AND THE PROMISE OF GLASS IN CONCRETE Case Study October 2016 1–11. Fathi, H., Fathi, A., 2016. Sugar beet fiber and Tragacanth gum effects on concrete. J. Clean. Prod. 112, 808–815. doi:10.1016/j.jclepro.2015.06.072 Flores-Medina, D., Flores Medina, N., Hernández-Olivares, F., 2014. Static mechanical properties of waste rests of recycled rubber and high quality recycled rubber from crumbed tyres used as aggregate in dry consistency concretes. Mater. Struct. Constr. 47, 1185–1193. doi:10.1617/s11527-013-0121-6 Flores Medina, N, Flores-Medina, D., Hernández-Olivares, F., 2016. Influence of fibers partially coated with rubber from tire recycling as aggregate on the acoustical properties of rubberized concrete. Constr. Build. Mater. 129, 25–36. doi:10.1016/j.conbuildmat.2016.11.007 Foglar, M., Hajek, R., Kovar, M., Štoller, J., 2015. Blast performance of RC panels with waste steel fibers. Constr. Build. Mater. 94, 536–546. doi:10.1016/j.conbuildmat.2015.07.082 Foti, D., 2011. Preliminary analysis of concrete reinforced with waste bottles PET fibers. Constr. Build. Mater. 25, 1906–1915. doi:10.1016/j.conbuildmat.2010.11.066 Foti, D., 2013. Use of recycled waste pet bottles fibers for the reinforcement of concrete. Compos. Struct. 96, 396–404. doi:10.1016/j.compstruct.2012.09.019 Foti, D., Paparella, F., 2014. Impact behavior of structural elements in concrete reinforced with PET grids. Mech. Res. Commun. 57, 57–66. doi:10.1016/j.mechrescom.2014.02.007 Foti, D., 2016. Innovative techniques for concrete reinforcement with polymers. Constr. Build. Mater. 112, 202–209. doi:10.1016/j.conbuildmat.2016.02.111 Fraternali, F., Ciancia, V., Chechile, R., Rizzano, G., Feo, L., Incarnato, L., 2011. Experimental study of the thermo-mechanical properties of recycled PET fiber-reinforced concrete. Compos. Struct. 93, 2368–2374. doi:10.1016/j.compstruct.2011.03.025 Fraternali, F., Spadea, S., Berardi, V.P., 2014. Effects of recycled PET fibres on the mechanical

Journal Pre-proof 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447

properties and seawater curing of Portland cement-based concretes. Constr. Build. Mater. 61, 293–302. doi:10.1016/j.conbuildmat.2014.03.019 García, D., Vegas, I., Cacho, I., 2014. Mechanical recycling of GFRP waste as short-fiber reinforcements in microconcrete. Constr. Build. Mater. 64, 293–300. doi:10.1016/j.conbuildmat.2014.02.068 Ghernouti, Y., Rabehi, B., Bouziani, T., Ghezraoui, H., Makhloufi, A., 2015. Fresh and hardened properties of self-compacting concrete containing plastic bag waste fibers (WFSCC). Constr. Build. Mater. 82, 89–100. doi:10.1016/j.conbuildmat.2015.02.059 Girardi, F., Giannuzzi, G.M., Mazzei, D., Salomoni, V., Majorana, C., Di Maggio, R., 2017. Recycled additions for improving the thermal conductivity of concrete in preparing energy storage systems. Constr. Build. Mater. 135, 565–579. doi:10.1016/j.conbuildmat.2016.12.179 Goyal, P., Rahman, Z., Kazmi, a a, 2013. Corporate sustainability performance and firm performance research: Literature review and future research agenda. Manag. Decis. 51, 361– 379. doi:10.1108/00251741311301867 Graeff, A.G., Pilakoutas, K., Neocleous, K., Peres, M.V.N.N., 2012. Fatigue resistance and cracking mechanism of concrete pavements reinforced with recycled steel fibres recovered from postconsumer tyres. Eng. Struct. 45, 385–395. doi:10.1016/j.engstruct.2012.06.030 Grinys, A., Sivilevičius, H., Pupeikis, D., Ivanauskas, E., 2013. Fracture of concrete containing crumb rubber. J. Civ. Eng. Manag. 19, 447–455. doi:10.3846/13923730.2013.782335 Groli, G., Pérez Caldentey, A., Soto, A.G., 2014. Cracking performance of SCC reinforced with recycled fibres An experimental study. Struct. Concr. 15, 136–153. doi:10.1002/suco.201300008 Groli, G., Pérez Caldentey, A., Marchetto, F., Aríñez Fernández, F., 2015. Serviceability performance of FRC columns under imposed displacements: An experimental study. Eng. Struct. 101, 450–464. doi:10.1016/j.engstruct.2015.07.035 Groli, G., Caldentey, A.P., 2017. Improving cracking behaviour with recycled steel fibres targeting specific applications – analysis according to fib Model Code 2010. Struct. Concr. 18, 29–39. doi:10.1002/suco.201500170 Gu, L., Ozbakkaloglu, T., 2016. Use of recycled plastics in concrete: A critical review. Waste Manag. doi:10.1016/j.wasman.2016.03.005 Guendouz, M., Debieb, F., Boukendakdji, O., Kadri, E.H., Bentchikou, M., Soualhi, H., 2016. Use of plastic waste in sand concrete. J. Mater. Environ. Sci. 7, 382–389. Gupta, T., Sharma, R.K., Chaudhary, S., 2015. Impact resistance of concrete containing waste rubber fiber and silica fume. Int. J. Impact Eng. 83, 76–87. doi:10.1016/j.ijimpeng.2015.05.002 Gupta, T., Siddique, S., Sharma, R.K., Chaudhary, S., 2017a. Effect of elevated temperature and cooling regimes on mechanical and durability properties of concrete containing waste rubber fiber. Constr. Build. Mater. 137, 35–45. doi:10.1016/j.conbuildmat.2017.01.065 Gupta, T., Tiwari, A., Siddique, S., Sharma, R.K., Chaudhary, S., 2017b. Response assessment under dynamic loading and microstructural investigations of rubberized concrete. J. Mater. Civ. Eng. 29. doi:10.1061/(ASCE)MT.1943-5533.0001905 Haghi, A.K., Beglou, M.Y., 2009. Fibre-reinforced polystyrene concrete. Advanced composite of tomorrow. J. Balk. Tribol. Assoc. 15, 493–503. Hama, S M, 2017. Improving mechanical properties of lightweight Porcelanite aggregate concrete using different waste material. Int. J. Sustain. Built Environ. 6, 81–90. doi:10.1016/j.ijsbe.2017.03.002 Hamoush, S.A.A., Carolina, N., El-Hawary, M.M., 1994. Feather fiber reinforced concrete. Concr. Int. 16, 33–35. Hassani, A., Arjmandi, M., 2010. Enhancement of concrete properties for pavement slabs using waste metal drillings and silica fume. Waste Manag. Res. 28, 56–63. doi:10.1177/0734242X09104143 Henry, M., Kato, Y., 2014. Understanding the regional context of sustainable concrete in Asia: Case studies in Mongolia and Singapore. Resour. Conserv. Recycl. 82, 86–93. doi:10.1016/j.resconrec.2013.10.012 Islam, G.M.S., Das Gupta, S., 2016. Evaluating plastic shrinkage and permeability of polypropylene fiber reinforced concrete. Int. J. Sustain. Built Environ. 5, 345–354. doi:10.1016/j.ijsbe.2016.05.007 Ismail, F.A., Sandi, R., Jauhari, Z. Al, 2017. The Influence of Steel Fibers Extracted from Waste Tyre

Journal Pre-proof 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504

on Properties of Concrete Containing Fly Ash. Int. J. Adv. Sci. Eng. Inf. Technol. 7, 2232–2236. Jafarifar, N., Pilakoutas, K., Bennett, T., 2014. Moisture transport and drying shrinkage properties of steel-fibre-reinforced-concrete. Constr. Build. Mater. 73, 41–50. doi:10.1016/j.conbuildmat.2014.09.039 Jafarifar, N., Pilakoutas, K., Bennett, T., 2016. The effect of shrinkage cracks on the load bearing capacity of steel-fibre-reinforced roller-compacted-concrete pavements. Mater. Struct. Constr. 49, 2329–2347. doi:10.1617/s11527-015-0652-0 Jafarifar, N., Pilakoutas, K., Angelakopoulos, H., Bennett, T., 2017. Post-cracking tensile behaviour of steel-fibre-reinforced roller-compacted-concrete for FE modelling and design purposes. Mater. Constr. 67, 1–12. doi:10.3989/mc.2017.06716 Jalal, M., 2012. Compressive strength enhancement of concrete reinforced by waste steel fibers utilizing nano SiO2. Middle East J. Sci. Res. 12, 382–391. doi:10.5829/idosi.mejsr.2012.12.3.1984 James, A.F., Rasool, M.A., Ganesh, S., 2017. Effect of hair fibre and GGBS on various properties of concrete-an experimental study. Int. J. Civ. Eng. Technol. 8, 648–653. Jandiyal, A., Salhotra, S., Sharma, R., Nazir, U., 2016. A review on using fibers made from waste PET bottles in concrete. Int. J. Civ. Eng. Technol. 7, 553–564. Jarabo, R., Fuente, E., Monte, M.C., Savastano, H., Mutjé, P., Negro, C., 2012. Use of cellulose fibers from hemp core in fiber-cement production. Effect on flocculation, retention, drainage and product properties. Ind. Crops Prod. 39, 89–96. doi:10.1016/j.indcrop.2012.02.017 Jawaid, M., Abdul Khalil, H.P.S., 2011. Cellulosic/synthetic fibre reinforced polymer hybrid composites: A review. Carbohydr. Polym. 86, 1–18. doi:10.1016/j.carbpol.2011.04.043 Kakvand, P., Rahgozar, R., Ghalehnovi, M., Irandegani, M.A., 2014. Experimentally analysing compressive and tensile strengths of concrete containing steel waste fibres. Int. J. Struct. Eng. 5, 132–141. doi:10.1504/IJSTRUCTE.2014.060903 Kalpokaite-Dickuviene, R., Cesniene, J., Brinkiene, K., 2012. Influence of fibres content on performance parameters of refractory concrete. Mechanika 18, 498–502. doi:10.5755/j01.mech.18.5.2697 Kandasamy, R., Murugesan, R., 2011. Fibre reinforced concrete using domestic waste plastics as fibres. ARPN J. Eng. Appl. Sci. 6, 75–82. Kandasamy, R., Murugesan, R., 2012. Fiber reinforced self compacting concrete using domestic waste plastics as fibres. J. Eng. Appl. Sci. 7, 405–410. doi:10.3923/jeasci.2012.405.410 Kandasamy, R., Murugesan, R., 2014. Study on fibre reinforced concrete using manufactured sand as fine aggregate and domestic waste plastics as fibres. J. Struct. Eng. 40, 521–531. Karanth, S.S., Ghorpade, V.G., Rao, H.S., 2017. Shear and impact strength of waste plastic fibre reinforced concrete. Adv. Concr. Constr. 5, 173–182. doi:10.12989/acc.2017.5.2.173 Karthik, M.P., Maruthachalam, D., 2014. Experimental study on shear behaviour of hybrid Fibre Reinforced Concrete beams. KSCE J. Civ. Eng. 19, 259–264. doi:10.1007/s12205-013-2350-1 Karthikeyan, S., Vennila, G., 2015. Analysis of compressive strength of concrete using polyethylene terephthalate [PET] fibres. Int. J. Appl. Eng. Res. 10, 34776–34778. Kendall, A., Keoleian, G.A., Lepech, M.D., 2008. Materials design for sustainability through life cycle modeling of engineered cementitious composites. Mater. Struct. Constr. 41, 1117–1131. doi:10.1617/s11527-007-9310-5 Keyvani, A.S., Saeki, N., 1997. Behavior of fiber concrete composites using recycled steel shavings. J. Solid Waste Technol. Manag. 24, [d]1-8. Khalid, F.S., Juki, M.I., Othman, N., Ibrahim, M.H.W., 2017. Pull-out strength of polyethylene terephthalate bottle fibre in concrete matrix. Malaysian Constr. Res. J. 21, 75–85. Khaloo, A.R., Esrafili, A., Kalani, M., Mobini, M.H., 2015. Use of polymer fibres recovered from waste car timing belts in high performance concrete. Constr. Build. Mater. 80, 31–37. doi:10.1016/j.conbuildmat.2015.01.011 Kharbuki, M., Malik, A., 2017. Study on partial replacement of cement by fly ash, natural fine aggregates by sawdust, and coir as a fibre in concrete. Int. J. Mech. Eng. Technol. 8, 1669– 1675. Khasreen, M.M., Banfill, P.F.G., Menzies, G.F., 2009. Life-cycle assessment and the environmental impact of buildings: A review. Sustainability 1, 674–701. doi:10.3390/su1030674 Khushnood, R.A., Ahmad, S., Ferro, G.A., Restuccia, L., Tulliani, J.M., Jagdale, P., 2015. Modified fracture properties of cement composites with nano/micro carbonized bagasse fibers. Frat. ed

Journal Pre-proof 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561

Integrita Strutt. 9, 534–542. doi:10.3221/IGF-ESIS.34.59 Kim, S.B., Yi, N.H., Kim, H.Y., Kim, J.H.J., Song, Y.C., 2010. Material and structural performance evaluation of recycled PET fiber reinforced concrete. Cem. Concr. Compos. 32, 232–240. doi:10.1016/j.cemconcomp.2009.11.002 Kitcharoen, K., 2004. The importance-performance analysis of service quality in administrative departments of private universities in Thailand. ABAC J. 24, 20–46. Koo, B.-M., Kim, J.-H.J., Kim, S.-B., Mun, S., 2014. Material and Structural performance evaluations of Hwangtoh admixtures and recycled PET fiber-added eco-friendly concrete for CO2 emission reduction. Materials (Basel). 7, 5959–5981. doi:10.3390/ma7085959 Kumar, B.H., Prakash, N., 2016. Studies on strength and weight loss of paper concrete. Proc. Inst. Civ. Eng. - Eng. Sustain. 169, 39–44. doi:10.1680/ensu.14.00057 Kurup, A.R., Kumar, K.S., 2017a. Effect of recycled PVC fibers from electronic waste and silica powder on shear strength of concrete. J. Hazardous, Toxic, Radioact. Waste 21. doi:10.1061/(ASCE)HZ.2153-5515.0000354 Kurup, A.R., Kumar, K.S., 2017b. Novel fibrous concrete mixture made from recycled PVC fibers from electronic waste. J. Hazardous, Toxic, Radioact. Waste 21. doi:10.1061/(ASCE)HZ.21535515.0000338 Lee, S.J., Rust, J.P., Hamouda, H., Kim, Y.R., Borden, R.H., 2005. Fatigue Cracking Resistance of Fiber-Reinforced Asphalt Concrete. Text. Res. J. 75, 123–128. doi:10.1177/004051750507500206 Lehne, J., Preston, F., 2018. Making Concrete Change Innovation in Low-carbon Cement and Concrete. Chatham House Rep. 1–122. doi:10.1088/1742-6596/1015/3/032163 Lejano, B., Gagan, J., 2017. Optimization of Compressive Strength of Concrete With Pig-Hair Fibers As Fiber Reinforcement and Green Mussel Shells As Partial Cement Substitute. Int. J. GEOMATE 12, 37–44. doi:10.21660/2017.31.6528 Leone, M., Centonze, G., Colonna, D., Micelli, F., Aiello, M.A., 2016. Experimental Study on Bond Behavior in Fiber-Reinforced Concrete with Low Content of Recycled Steel Fiber. J. Mater. Civ. Eng. 28. doi:10.1061/(ASCE)MT.1943-5533.0001534 Li, D., Mills, J.E., Benn, T., Ma, X., Gravina, R., Zhuge, Y., 2016. Review of the performance of highstrength rubberized concrete and its potential structural applications. Adv. Civ. Eng. Mater. 5, 149–166. doi:10.1520/ACEM20150026 Li, G., Garrick, G., Eggers, J., Abadie, C., Stubblefield, M.A., Pang, S.-S., 2004a. Waste tire fiber modified concrete. Compos. Part B Eng. 35, 305–312. doi:10.1016/j.compositesb.2004.01.002 Li, G., Stubblefield, M.A., Garrick, G., Eggers, J., Abadie, C., Huang, B., 2004b. Development of waste tire modified concrete. Cem. Concr. Res. 34, 2283–2289. doi:10.1016/j.cemconres.2004.04.013 Lieder, M., Rashid, A., 2016. Towards circular economy implementation: A comprehensive review in context of manufacturing industry. J. Clean. Prod. 115, 36–51. doi:10.1016/j.jclepro.2015.12.042 Liu, Y., Zhang, Y., Guo, Y., Chu, P.K., Tu, S., 2017. Porous Materials Composed of Flue Gas Desulfurization Gypsum and Textile Fiber Wastes. Waste and Biomass Valorization 8, 203– 207. doi:10.1007/s12649-016-9617-y Machovič, V., Kopecký, L., Němeček, J., Kolář, F., Svítilová, J., Bittnar, Z., Andertová, J., 2008. Raman micro-spectroscopy mapping and microstructural and micromechanical study of interfacial transition zone in concrete reinforced by poly(ethylene terephthalate) fibres. Ceram. - Silikaty 52, 54–60. Machovič, V., Lapčák, L., Borecká, L., Lhotka, M., Andertová, J., Kopecký, L., Mišková, L., 2013. Microstructure of interfacial transition zone between PET fibres and cement paste. Acta Geodyn. Geomater. 10, 121–127. doi:10.13168/AGG.2013.0012 Mahasneh, B.Z., 2005. The Effect of Addition of Fiber Reinforcement on Fire Resistant Composite Concrete Material. J. Appl. Sci. 5, 373–379. Malaiškiene, J., Nagrockiene, D., Skripkiunas, G., 2015. Possibilities to use Textile Cord Waste from Used Tires for Concrete. J. Environ. Eng. Landsc. Manag. 23, 183–191. doi:10.3846/16486897.2015.1057514 Mangat, P.S., Gurusamy, K., 1988. Long term properties under marine exposure of steel fibre reinforced concrete containing pfa. Mater. Struct. 21, 352–358. doi:10.1007/BF02472161 Manivel, S., Kumar, S.N., Prakashchandar, S., Kumar, S.A., 2017. Experimental Study on Human

Journal Pre-proof 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618

Hair Fiber Reinforced Concrete With Partial Replacement of Cement by GGBFS 8, 1145–1155. Marinković, S., Dragaš, J., Ignjatović, I., Tošić, N., 2017. Environmental assessment of green concretes for structural use. J. Clean. Prod. 154, 633–649. doi:10.1016/j.jclepro.2017.04.015 Martinelli, E., Caggiano, A., Xargay, H., 2015. An experimental study on the post-cracking behaviour of Hybrid Industrial/Recycled Steel Fibre-Reinforced Concrete. Constr. Build. Mater. 94, 290– 298. doi:10.1016/j.conbuildmat.2015.07.007 Martínez-Barrera, G., Martínez-López, M., González-Rivas, N., del Coz-Diaz, J.J., Ávila-Córdoba, L., Reis, J.M.L. dos, Gencel, O., 2017. Recycled cellulose from Tetra Pak packaging as reinforcement of polyester based composites. Constr. Build. Mater. 157, 1018–1023. doi:10.1016/j.conbuildmat.2017.09.181 Mastali, M., Dalvand, A., Sattarifard, A.R., 2016. The impact resistance and mechanical properties of reinforced self-compacting concrete with recycled glass fibre reinforced polymers. J. Clean. Prod. 124, 312–324. doi:10.1016/j.jclepro.2016.02.148 Mastali, M., Dalvand, A., 2016a. Use of silica fume and recycled steel fibers in self-compacting concrete (SCC). Constr. Build. Mater. 125, 196–209. doi:10.1016/j.conbuildmat.2016.08.046 Mastali, M., Dalvand, A., 2016b. The impact resistance and mechanical properties of selfcompacting concrete reinforced with recycled CFRP pieces. Compos. Part B Eng. 92, 360–376. doi:10.1016/j.compositesb.2016.01.046 Mastali, M., Dalvand, A., Sattarifard, A., 2017. The impact resistance and mechanical properties of the reinforced self-compacting concrete incorporating recycled CFRP fiber with different lengths and dosages. Compos. Part B Eng. 112, 74–92. doi:10.1016/j.compositesb.2016.12.029 Mastali, M., Dalvand, A., 2017a. Fresh and Hardened Properties of Self-Compacting Concrete Reinforced with Hybrid Recycled Steel – Polypropylene Fiber. J. Mater. Civ. Eng. 29, 1–15. doi:10.1061/(ASCE)MT.1943-5533.0001851. Mastali, M., Dalvand, A., 2017b. Fresh and hardened properties of self-compacting concrete reinforced with hybrid recycled steel-polypropylene fiber. J. Mater. Civ. Eng. 29. doi:10.1061/(ASCE)MT.1943-5533.0001851 Mayring, P., 2003. Qualitative Inhaltsanayse (Qualitative Content Analysis), Qualitative Marktforschung. Meddah, M.S., Bencheikh, M., 2009. Properties of concrete reinforced with different kinds of industrial waste fibre materials. Constr. Build. Mater. 23, 3196–3205. doi:10.1016/j.conbuildmat.2009.06.017 Medina, N.F., Medina, D.F., Hernández-Olivares, F., Navacerrada, M.A., 2017. Mechanical and thermal properties of concrete incorporating rubber and fibres from tyre recycling. Constr. Build. Mater. 144, 563–573. doi:10.1016/j.conbuildmat.2017.03.196 Meena, T., Elangovan, G., 2014. An experimental study on fresh and hardened state properties of fibre reinforced Self Compacting Concrete using different types of fibres. Inf. 17, 2915–2924. Mello, E., Ribellato, C., Mohamedelhassan, E., 2014. Improving Concrete Properties with Fibers Addition. Int. Sch. Sci. Res. Innov. 8, 245–250. Merli, R., Preziosi, M., Acampora, A., 2018. How do scholars approach the circular economy? A systematic literature review. J. Clean. Prod. 178, 703–722. doi:10.1016/j.jclepro.2017.12.112 Meyer, C., 2004. Concrete materials and Sustainable Dvelopment in the USA. Struct. Eng. Int. J. Int. Assoc. Bridg. Struct. Eng. Meyer, C., 2009. The greening of the concrete industry. Cem. Concr. Compos. 31, 601–605. doi:10.1016/j.cemconcomp.2008.12.010 Mo, K.H., Alengaram, U.J., Jumaat, M.Z., Yap, S.P., Lee, S.C., 2016. Green concrete partially comprised of farming waste residues: A review. J. Clean. Prod. doi:10.1016/j.jclepro.2016.01.022 Mohamed, M.A.S., Ghorbel, E., Wardeh, G., 2010. Valorization of micro-cellulose fibers in selfcompacting concrete. Constr. Build. Mater. 24, 2473–2480. doi:10.1016/j.conbuildmat.2010.06.009 Mohammadhosseini, H., Yatim, J.M., 2017. Microstructure and residual properties of green concrete composites incorporating waste carpet fibers and palm oil fuel ash at elevated temperatures. J. Clean. Prod. 144, 8–21. doi:10.1016/j.jclepro.2016.12.168 Mohammadhosseini, Hossein, Abdul Awal, A.S.M., Mohd Yatim, J.B., 2017a. The impact resistance and mechanical properties of concrete reinforced with waste polypropylene carpet fibres. Constr. Build. Mater. 143, 147–157. doi:10.1016/j.conbuildmat.2017.03.109

Journal Pre-proof 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675

Mohammadhosseini, Hossein, Yatim, J.M., Sam, A.R.M., Awal, A.S.M.A., 2017b. Durability performance of green concrete composites containing waste carpet fibers and palm oil fuel ash. J. Clean. Prod. 144, 448–458. doi:10.1016/j.jclepro.2016.12.151 Murali, G., Chandana, V., 2017. Weibull reliability analysis of impact resistance on selfcompacting concrete reinforced with recycled CFRP pieces. Romanian J. MAter. 47, 196–203. Myers, D., 2005. A review of construction companies’ attitudes to sustainability. Constr. Manag. Econ. doi:10.1080/01446190500184360 Naik, T.R., Friberg, T.S., Chun, Y.-M., 2004. Use of pulp and paper mill residual solids in production of cellucrete. Cem. Concr. Res. 34, 1229–1234. doi:10.1016/j.cemconres.2003.12.013 Nehdi, M., Ladanchuk, J.D., 2004. Fiber synergy in fiber-reinforced self-consolidating concrete. ACI Mater. J. 101, 508–517. doi:10.14359/13490 Nehdi, M.L., Najjar, M.F., Soliman, A.M., Azabi, T.M., 2017. Novel eco-efficient Two-Stage Concrete incorporating high volume recycled content for sustainable pavement construction. Constr. Build. Mater. 146, 9–14. doi:10.1016/j.conbuildmat.2017.04.065 Neocleous, K., Angelakopoulos, H., Pilakoutas, K., Guadagnin, M., 2011. Fibre-reinforced roller compacted concrete transport pavements. Proc. Inst. Civ. Eng. Transp. 164, 97–109. doi:10.1680/tran.9.00043 Nibudey, R.N., Nagarnaik, P.B., Parbat, D.K., Pande, A.M., 2015. A comparative study of various fibers and waste plastic fiber reinforced concrete. J. Struct. Eng. 42, 256–263. Ochi, T., Okubo, S., Fukui, K., 2007. Development of recycled PET fiber and its application as concrete-reinforcing fiber. Cem. Concr. Compos. 29, 448–455. doi:10.1016/j.cemconcomp.2007.02.002 Ogi, K., Shinoda, T., Mizui, M., 2005. Strength in concrete reinforced with recycled CFRP pieces. Compos. Part A Appl. Sci. Manuf. 36, 893–902. doi:10.1016/j.compositesa.2004.12.009 Othuman Mydin, M.A., Rozlan, N.A., Ganesan, S., 2015. Experimental Study on the Mechanical Properties of Coconut Fibre Reinforced Lightweight Foamed Concrete. Environ. Sci 6, 407–411. Otuoze, H.S., Amartey, Y.D., Joel, M., Momoh, R.O., Shuaibu, A.A., Yusuf, K.O., 2015. Assessment of dynamic modulus of high density polypropylene waste fiber reinforcement in asphalt concrete. Leonardo Electron. J. Pract. Technol. 14, 13–30. Ozerkan, N.G., Tokgoz, D.D.G., Kowita, O.S., Antony, S.J., 2016. Assessment of microstructural and mechanical properties of hybrid fibrous self-consolidating concretes using ingredients of plastic wastes. Nat. Environ. Pollut. Technol. 15. Ozger, O.B., Girardi, F., Giannuzzi, G.M., Salomoni, V.A., Majorana, C.E., Fambri, L., Baldassino, N., Di Maggio, R., 2013. Effect of nylon fibres on mechanical and thermal properties of hardened concrete for energy storage systems. Mater. Des. 51, 989–997. doi:10.1016/j.matdes.2013.04.085 Pacheco-Torgal, F., Jalali, S., 2011. Cementitious building materials reinforced with vegetable fibres: A review. Constr. Build. Mater. 25, 575–581. doi:10.1016/j.conbuildmat.2010.07.024 Parameswaran, V.S., 1991. Fibre-reinforced concrete: a versatile construction material. Build. Environ. 26, 301–305. doi:10.1016/0360-1323(91)90054-F Pelisser, F., Neto, A.B.D.S.S., Rovere, H.L. La, Pinto, R.C.D.A., 2010. Effect of the addition of synthetic fibers to concrete thin slabs on plastic shrinkage cracking. Constr. Build. Mater. 24, 2171–2176. doi:10.1016/j.conbuildmat.2010.04.041 Pelisser, F., Montedo, O.R.K., Gleize, P.J.P., Roman, H.R., 2012. Mechanical properties of recycled PET fibers in concrete. Mater. Res. 15, 679–686. doi:10.1590/S1516-14392012005000088 Pereira, E.L., de Oliveira Junior, A.L., Fineza, A.G., 2017. Optimization of mechanical properties in concrete reinforced with fibers from solid urban wastes (PET bottles) for the production of ecological concrete. Constr. Build. Mater. 149, 837–848. doi:10.1016/j.conbuildmat.2017.05.148 Pešić, N., Živanović, S., Garcia, R., Papastergiou, P., 2016. Mechanical properties of concrete reinforced with recycled HDPE plastic fibres. Constr. Build. Mater. 115, 362–370. doi:10.1016/j.conbuildmat.2016.04.050 Petek Gursel, A., Masanet, E., Horvath, A., Stadel, A., 2014. Life-cycle inventory analysis of concrete production: A critical review. Cem. Concr. Compos. 51, 38–48. doi:10.1016/j.cemconcomp.2014.03.005 Prem Kumar, S., Ahmed Ibrahim, S.N., Illayaraja, K., 2014. A study on strength characteristics of concrete using polyethylene waste as a fibre. Int. J. Appl. Eng. Res. 9, 5439–5442.

Journal Pre-proof 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732

Pujadas, P., Blanco, A., Cavalaro, S., Aguado, A., 2014. Plastic fibres as the only reinforcement for flat suspended slabs: Experimental investigation and numerical simulation. Constr. Build. Mater. 57, 92–104. doi:10.1016/J.CONBUILDMAT.2014.01.082 Rashid, K., Balouch, N., 2017. Influence of steel fibers extracted from waste tires on shear behavior of reinforced concrete beams. Struct. Concr. 18, 589–596. doi:10.1002/suco.201600194 Rebeiz, B.K.S., Fowler, D.W., Paup, D.R., 1993. RECYCLING PLASTICS IN POLYMER CONCRETE FOR CONSTRUCTION APPLICATIONS 5, 237–248. Reis, J.M.L., 2006. Fracture and flexural characterization of natural fiber-reinforced polymer concrete. Constr. Build. Mater. 20, 673–678. doi:10.1016/j.conbuildmat.2005.02.008 Rhee, I., Kim, J.H., Park, S.H., Lee, S., Ryu, B.R., Kim, Y.A., 2017. Mechanical and electrical properties of cement paste incorporated with Pitch-Based carbon fiber. Carbon Lett. 23, 22–29. doi:10.5714/CL.2017.23.022 Rinu Isah, R.J., Shruthi, M. V, 2017. Utilization of waste pet bottle fibres in reinforced concrete. Int. J. Pure Appl. Math. 116, 579–584. Ruben, J.S., Baskar, G., 2014. Behavioural study on latex treated waste coir fiber in concrete composites. Pollut. Res. 33, 233–236. Sadrmomtazi, A., Sobhani, J., Mirgozar, M.A., Najimi, M., 2012. Properties of multi-strength grade EPS concrete containing silica fume and rice husk ash. Constr. Build. Mater. 35, 211–219. doi:10.1016/j.conbuildmat.2012.02.049 Salim, N., Ab Rahman, M.N., Abd Wahab, D., 2019. A systematic literature review of internal capabilities for enhancing eco-innovation performance of manufacturing firms. J. Clean. Prod. doi:10.1016/j.jclepro.2018.11.105 Sánchez, A.D., de la Cruz Del Río Rama, M., García, J.Á., 2016. Bibliometric analysis of publications on wine tourism in the databases Scopus and WoS. Eur. Res. Manag. Bus. Econ. 1–8. doi:10.1016/j.iedeen.2016.02.001 Sarabi, S., Bakhshi, H., Sarkardeh, H., Nikoo, H.S., 2017. Thermal stress control using waste steel fibers in massive concretes. Eur. Phys. J. Plus 132, 491. doi:10.1140/epjp/i2017-11758-3 Schmidt, H., Cieślak, M., 2008. Concrete with carpet recyclates: Suitability assessment by surface energy evaluation. Waste Manag. 28, 1182–1187. doi:10.1016/j.wasman.2007.05.005 Schwarzova, I., Stevulova, N., Melichar, T., 2017. Lightweight composites based on technical hemp hurds in construction industry. Chem. Eng. Trans. 57, 1369–1374. doi:10.3303/CET1757229 Sebaibi, N., Benzerzour, M., Abriak, N.E., 2014. Influence of the distribution and orientation of fibres in a reinforced concrete with waste fibres and powders. Constr. Build. Mater. 65, 254–263. doi:10.1016/j.conbuildmat.2014.04.134 Sekar, T., 2004. Fibre reinforced concrete from industrial waste fibres - A feasibility study. J. Inst. Eng. Civ. Eng. Div. 84, 287–290. Sengul, O., 2016. Mechanical behavior of concretes containing waste steel fibers recovered from scrap tires. Constr. Build. Mater. 122, 649–658. doi:10.1016/j.conbuildmat.2016.06.113 Serdar, M., Baričević, A., Bjegović, D., Lakušć, S., 2014. Possibilities of use of products from waste tyre recycling in concrete industry. J. Appl. Eng. Sci. 12, 89–93. doi:10.5937/jaes12-5671 Serdar, M, Baričević, A., Jelčić Rukavina, M., Pezer, M., Bjegović, D., Štirmer, N., 2015. Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres. Int. J. Polym. Sci. 2015. doi:10.1155/2015/145918 Seuring, S., Müller, M., 2008. From a literature review to a conceptual framework for sustainable supply chain management. J. Clean. Prod. 16, 1699–1710. doi:10.1016/j.jclepro.2008.04.020 Sharma, R., Bansal, P.P., 2016. Use of different forms of waste plastic in concrete - A review. J. Clean. Prod. doi:10.1016/j.jclepro.2015.08.042 Sharma, A., Singh, J., 2017. The study of strength characteristic of concrete by adding coir fibre and replacement of steel slag. Int. J. Mech. Eng. Technol. 8, 1814–1822. Sharma, S., Singh, J., 2017a. Impact of partial replacement of cement with rice husk ash and proportionate addition of coconut fibre on concrete. Int. J. Mech. Eng. Technol. 8, 1806–1813. Shi, C., Zheng, K., 2007. A review on the use of waste glasses in the production of cement and concrete. Resour. Conserv. Recycl. 52, 234–247. doi:10.1016/j.resconrec.2007.01.013 Shukla, M., Jharkharia, S., 2013. Agri‐fresh produce supply chain management: a state‐of‐the‐art literature review. Int. J. Oper. Prod. Manag. 33, 114–158. doi:10.1108/01443571311295608 Sivaraja, M., Kandasamy, S., 2010. Potential reuse of waste rice husk as fibre composites in concrete. Asian J. Civ. Eng. 12, 205–217.

Journal Pre-proof 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789

Sivaraja, M, Kandasamy, S., Thirumurugan, A., 2010. Mechanical strength of fibrous concrete with waste rural materials. J. Sci. Ind. Res. (India). 69, 308–312. Sodhi, V., Salhotra, S., 2017. Utilising wastes as partial replacement in concrete - A review. Int. J. Civ. Eng. Technol. 8, 636–641. Sofi, A., 2017. Effect of waste tyre rubber on mechanical and durability properties of concrete - A review. Ain Shams Eng. J. doi:10.1016/j.asej.2017.08.007 Soroushian, P., Plasencia, J., Ravanbakhsh, S., 2003. Assessment of reinforcing effects of recycled plastic and paper in concrete. ACI Mater. J. 100, 203–207. Sotoudeh, M.H., Jalal, M., 2013. Effects of waste steel fibers on strength and stress-strain behavior of concrete incorporating silica nanopowder. Indian J. Sci. Technol. 6, 5411–5417. Spadea, S., Farina, I., Berardi, V.P., Dentale, F., Fraternali, F., 2014. Energy dissipation capacity of concretes reinforced with recycled PET fibers. Ing. Sismica 31, 61–70. Stier, K.W., Weede, G.D., 1998. A study conducted to investigate the feasibility of recycling commingled plastics fiber in concrete. J. Ind. Technol. 15. Subramaniaprasad, C.K., Abraham, B.M., Kunhanandan Nambiar, E.K., 2015. Influence of embedded waste-plastic fibers on the improvement of the tensile strength of stabilized mud masonry blocks. J. Mater. Civ. Eng. 27. doi:10.1061/(ASCE)MT.1943-5533.0001165 Sumathi, A., Saravana Raja Mohan, K., 2015. Study on the strength and durability characteristics of high strength concrete with steel fibers. Int. J. ChemTech Res. 8, 241–248. Thirumurugan, A., Sivaraja, M., 2013. Workability and strength properties of hybrid fibre reinforced concrete from industrial waste. Asian J. Civ. Eng. 14, 477–485. Thirumurugan, A., Sivaraja, M., 2015. Strength And Fracture Properties Of Hybrid Fibre Reinforced Concrete. IJST, Trans. Civ. Eng. 39, 273–282. Tlemat, H., Pilakoutas, K., Neocleous, K., 2006. Stress-strain characteristic of SFRC using recycled fibres. Mater. Struct. Constr. 39, 365–377. doi:10.1617/s11527-005-9009-4 Torkaman, J., Ashori, A., Sadr Momtazi, A., 2014. Using wood fiber waste, rice husk ash, and limestone powder waste as cement replacement materials for lightweight concrete blocks. Constr. Build. Mater. 50, 432–436. doi:10.1016/j.conbuildmat.2013.09.044 Turk, J., Cotic, Z., Mladenovic, A., Sajna, A., 2015. Environmental evaluation of green concretes versus conventional concrete by means of LCA. Waste Manag. 45, 194–205. doi:10.1016/j.wasman.2015.06.035 Ucar, M., Wang, Y., 2011. Utilization of recycled post consumer carpet waste fibers as reinforcement in lightweight cementitious composites. Int. J. Cloth. Sci. Technol. 23, 242–248. doi:10.1108/09556221111136502 United Nations, 2015. Transforming our world: the 2030 Agenda for Sustainable Development. Usman, N., Masirin, M.I.B.M., Ahmad, K.A., Wurochekke, A.A., 2016. Reinforcement of asphalt concrete mixture using recycle polyethylene terephthalate fibre. Indian J. Sci. Technol. 9. doi:10.17485/ijst/2016/v9i46/107143 Van Den Heede, P., De Belie, N., 2012. Environmental impact and life cycle assessment (LCA) of traditional and “green” concretes: Literature review and theoretical calculations. Cem. Concr. Compos. 34, 431–442. doi:10.1016/j.cemconcomp.2012.01.004 van Eck, N.J., Waltman, L., 2010. Software survey: VOSviewer, a computer program for bibliometric mapping. Scientometrics. doi:10.1007/s11192-009-0146-3 Vasudev, R., Vishnuram, B.G., 2014. Studies on flexural behaviour of beams with turn steel scrap as fibres – an ecofriendly approach. Int. J. Earth Sci. Eng. 7, 2055–2061. Vasudev, R., Vishnuram, B.G., 2014a. Experimental studies of the application of turn steel scraps as fibres in concrete - A rehabilitative approach. Int. J. Eng. Technol. 6, 1885–1899. Vieira, D.R., Calmon, J.L., Coelho, F.Z., 2016. Life cycle assessment (LCA) applied to the manufacturing of common and ecological concrete: A review. Constr. Build. Mater. 124, 656– 666. doi:10.1016/j.conbuildmat.2016.07.125 Vijaya, G.S., Ghorpade, V.G., Sudarsana Rao, H., 2016. The behaviour of self compacting concrete with waste plastic fibers when subjected to acid attack. Int. J. Eng. Technol. 8, 1521–1527. Vishnu, A., Mohana, V., Manasi, S., Ponmalar, V., 2017. Use of polyethylene terephthalate in concrete - A brief review. Int. J. Civ. Eng. Technol. 8, 1171–1176. Walraven, J.C., 2009. High performance fiber reinforced concrete: progress in knowledge and design codes. Mater. Struct. 42, 1247–1260. doi:10.1617/s11527-009-9538-3 Wang, Y., Zureick, A.-H., Cho, B.-S., Scott, D.E., 1994. Properties of fibre reinforced concrete using

Journal Pre-proof 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841

recycled fibres from carpet industrial waste. J. Mater. Sci. 29, 4191–4199. doi:10.1007/BF00414198 Wang, Y., 1997. Concrete reinforcement with recycled fibers from carpet industrial waste. J. Mater. Civ. Eng. 9, 103–104. doi:10.1061/(ASCE)0899-1561(1997)9:3(103) Wang, Y., 1998. Toughness characteristics of synthetic fibre-reinforced cementitious composites. Fatigue Fract. Eng. Mater. Struct. 21, 521–532. Wang, Y., 1999. Utilization of recycled carpet waste fibers for reinforcement of concrete and soil. Polym. Plast. Technol. Eng. 38, 533–546. doi:10.1080/03602559909351598 Wang, Y., Wu, H.C., Li, V.C., 2000. Concrete reinforcement with recycled fibers. J. Mater. Civ. Engeneering 12, 314–319. doi:10.1061/(ASCE)0899-1561(2000)12:4(314) Watkins, G., Mäkelä, M., Dahl, O., 2010. Innovative use potential of industrial residues from the steel, paper and pulp industries - A preliminary study. Prog. Ind. Ecol. 7, 185–204. doi:10.1504/PIE.2010.037775 Webster, J., Watson, R., 2002. Analyzing the Past To Prepare for the Future : Writing a Literature Review. MIS Q. 26, 13–23. doi:10.2307/4132319 Wong, D., 2018. VOSviewer. Tech. Serv. Q. doi:10.1080/07317131.2018.1425352 Xue, J., Shinozuka, M., 2013. Rubberized concrete: A green structural material with enhanced energy-dissipation capability. Constr. Build. Mater. 42, 196–204. doi:10.1016/j.conbuildmat.2013.01.005 Yang, S.F., Wang, T.M., Lee, W.C., Sun, K.S., Tzeng, C.C., 2010. Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete. J. Hazard. Mater. 182, 191–196. doi:10.1016/j.jhazmat.2010.06.014 Yazdanbakhsh, A., Bank, L.C., Chen, C., Tian, Y., 2017. FRP-Needles as discrete reinforcement in concrete. J. Mater. Civ. Eng. 29. doi:10.1061/(ASCE)MT.1943-5533.0002033 Yin, Shi, Tuladhar, R., Shi, F., Combe, M., Collister, T., Sivakugan, N., 2015. Use of macro plastic fibres in concrete: A review. Constr. Build. Mater. doi:10.1016/j.conbuildmat.2015.05.105 Yin, S, Tuladhar, R., Collister, T., Combe, M., Sivakugan, N., Deng, Z., 2015a. Post-cracking performance of recycled polypropylene fibre in concrete. Constr. Build. Mater. 101, 1069–1077. doi:10.1016/j.conbuildmat.2015.10.056 Yin, S, Tuladhar, R., Shanks, R.A., Collister, T., Combe, M., Jacob, M., Tian, M., Sivakugan, N., 2015b. Fiber preparation and mechanical properties of recycled polypropylene for reinforcing concrete. J. Appl. Polym. Sci. 132. doi:10.1002/app.41866 Yin, S., Tuladhar, R., Riella, J., Chung, D., Collister, T., Combe, M., Sivakugan, N., 2016. Comparative evaluation of virgin and recycled polypropylene fibre reinforced concrete. Constr. Build. Mater. 114, 134–141. doi:10.1016/j.conbuildmat.2016.03.162 Yina, S., Tuladhar, R., Sheehan, M., Combe, M., Collister, T., 2016. A life cycle assessment of recycled polypropylene fibre in concrete footpaths. J. Clean. Prod. 112, 2231–2242. doi:10.1016/j.jclepro.2015.09.073 Younis, K.H., Pilakoutas, K., 2013. Strength prediction model and methods for improving recycled aggregate concrete. Constr. Build. Mater. 49, 688–701. doi:10.1016/j.conbuildmat.2013.09.003 Yuzer, N., Cinar, Z., Akoz, F., Biricik, H., Gurkan, Y.Y., Kabay, N., Kizilkanat, A.B., 2013. Influence of raw rice husk addition on structure and properties of concrete. Constr. Build. Mater. 44, 54– 62. doi:10.1016/j.conbuildmat.2013.02.070 Zamanzadeh, Z., Lourenço, L., Barros, J., 2015. Recycled Steel Fibre Reinforced Concrete failing in bending and in shear. Constr. Build. Mater. 85, 195–207. doi:10.1016/j.conbuildmat.2015.03.070 Zollo, R.F., 1997. Fiber-reinforced concrete: an overview after 30 years of development. Cem. Concr. Compos. 19, 107–122. doi:10.1016/S0958-9465(96)00046-7 Zubaidi, R. Al, Barakat, S., Altoubat, S., 2013. Effects of adding brass byproduct on the basic properties of concrete. Constr. Build. Mater. 38, 236–241. doi:10.1016/j.conbuildmat.2012.07.108