- Email: [email protected]
Role of coconut coir fiber in concrete
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Role of coconut coir fiber in concrete Habibunnisa Syed a,⇑, Ruben Nerella a, Sri Rama Chand Madduru b a b
Department of Civil Engineering, Vignan’s Foundation for Science, Technology & Research (Deemed to be University), Vadlamudi, Guntur, Andhra Pradesh 522213, India Department of Civil Engineering, Sri Chaitanya Engineering College, Karimnagar, Telangana, India
a r t i c l e
i n f o
Article history: Received 7 December 2019 Received in revised form 23 January 2020 Accepted 25 January 2020 Available online xxxx Keywords: Coconut coir fiber reinforced concrete Compressive strength Fiber mesh Tensile strength Flexural strength Slump test
a b s t r a c t Now a days the cost of construction increases along with gradual effect on the environment and it has led the researchers to the acceptance of natural fibers such as coconut fibers for improving the strength in concrete. Coconut fibers that are abundantly accessible at the test site making it relatively applicable as a reinforcing material in concrete. Concrete with different fiber contents was evaluated with conventional concrete or prestressed concrete and different strengths parameters such as bending, compression and tensile strength of coconut fiber varies with a proportions (0.6% and 1.2%) of total weight of the volume of concrete coconut fiber is carried out. The effect of fiber shape on strength property studied by testing with coconut fiber mesh from pre-defined dimension. The optimum percentage of both treated fiber yarn and raw fiber nets was found with trial and error process and maximum percentage of super plasticizer needed to both ordinary cement as well as coconut fibers in the concrete for basic operability was also determined. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the First International conference on Advanced Lightweight Materials and Structures.
1. Introduction Fiber-like thread and material that is useful to various purposes. The fibers produces from plants (vegetables, wood, leaves), geological processes and animals are known as natural fibers [1]. The researchers uses natural plant fibers as a substitute material in steel and/or synthetic fibers for use in compounds(cement paste, cement mortar and/or concrete) to improve their strength properties [1]. These plant fibers are referred to as natural fibers, containing coconut fibers, sisal, jute, carp and cannabis, eucalyptus grandis, malva, ramie past, pineapple leaves, cannabis, aspheric leaves, abaca leaves, jaws, dates, bamboo, banana, palm, hemp And linen, cotton and sugar cane. Natural fibers are inexpensive and available in most of the countries. Therefore, their usage in building materials for properties of mounting compounds costs very little. The added benefit may also includes ease of use/easy to handle the fibers due to its flexible nature. The problem arises, when a high percentages of fiber used in steel fibers. But to use very high fiber content, a methodology for pouring is needed [2]. Fracture fragment and fiber content are terms used to express fiber quantities in a given compound. Reinforced compounds can be ⇑ Corresponding author. E-mail address: [email protected] (H. Syed).
used for many civil engineering applications including corrugated roof tiles, tiles, simple slabs, tiles and mortars [2].
1.1. Characteristics of coconut fiber Coconut fibers with strength of 21.51 MPa are strongest one among all natural fibers. It is able to take strains 4 to 6 times higher than other fibers [3]. Coconut fibers has examined by many researchers to various purposes. There are significant variations some of characteristics are, for example the diameter of the coconut fibers is almost identical and the amounts of tensile strength are relatively different, for example the fibroblasts of different individual cells were depends on type of plant, its location and puberty [3]. Elasticity and rupture of fibers was effected by length to diameter ratio of fibers it also determine the product from which they are manufactured. Shape and size of hollow central cavity. The cavity depend upon (1) Thickness of cell wall (2) Source of fibers. Hollow cavity, acts as a acoustic and thermal insulation due to existence reduces bulk density of fibers [3]. Coconut fiber contains cellulose, cellulose sugar and lignin as a main composition. These formulations effects dissimilar properties in coconut fibers [3]. Pre-treatment of fibers led to a change in composition and ultimate changes occur due to their properties and also their properties of composite materials. Sometimes it
https://doi.org/10.1016/j.matpr.2020.01.477 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the First International conference on Advanced Lightweight Materials and Structures.
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
2
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
improve behaviour of fibers. But, Sometimes it effect was unfavourable [4]. 2. Materials These are the following materials used in the manufacturing of concrete (Table 1). They are
Table 2 Cement properties. S. No
Property
Values obtained
Limit as per I.S 4031
01
Initial Setting time, Final Setting time Soundness Density Fineness Initial Setting time, Final Setting time
71 min, 300 min
>30
1 mm 3.099 g/cc 7.2% 71 min, 300 min
<10 mm 3.16 <10.01% >30
02 03 04 05
2.1. Cement Portland Pozzolana Cement produced by grinding together portland cement clinker and pozzolana with addition of gypsum or calcium sulphate or by intimately and uniformly blending portland cement and fine pozzolana. Calcined clay or fly ash is used for manufacture of PPC. It produce less heat of hydration and also reduces leaching of calcium hydroxide liberated during the setting and hydration of cement. 2.2. Coarse aggregate and fine aggregate Aggregates are the important material in concrete. They give body to the concrete, reduce shrinkage and effect economy. Aggregates Classified into fine aggregates and coarse aggregates. Aggregates most of which retained on I.S sieve 4.75 mm are Coarse aggregates, which passes through 4.75 mm known as fine aggregates. In this work manufactured sand and crushed aggregates passes through 20 mm I.S sieve are used as fine aggregate coarse aggregates respectively. 2.3. Coconut fiber Raw coconut fiber and processed coconut fiber both are used in this work. Treatment of fibers removes dust and other particles left on fiber so as to augment the surface of contact between fiber and mix resulting in better binding between reinforcement and concrete results ultimate high strength [5]. 2.4. Water According to I.S 456:2000, water used for mixing and curing shall be clean and free from injuries amounts of oils, acids, alkalis, salts, sugar and organic materials or any other substances that may detorious to concrete and steel. pH value of water used for mixing the concrete shall be less than 6.
3.2. Aggregate tests Aggregate is a vital component in concrete. It occupies 70% to 80% of volume of concrete. Its impact on the properties and characteristics of different concrete. Following tests performed on aggregates for determination different properties. 1. Specific gravity test on coarse aggregates. 2. Bulk density test on coarse aggregates. 3. Sieve analysis on coarse aggregates [5]. Standard I.S sieves are used for sieve analysis process of fine aggregates. As per I.S 2386, Bulk density lies between 1.2 and 1.8 g/cc and Specific gravity lies between 2.60 and 2.80 (Table 3). 3.3. Processed coconut fibers Only processed coconut fiber is used in this research. They are appropriately washed and tied into yarns before usage. Fiber processing remove dust and residual particles remaining on fibers to increases contact surface between fibers and the mix results in improved bonding between reinforcement, concrete and ultimate higher strength. Fibers are washes in running tap water for about 30 min to lose fibers and to remove coconut dust. After wash the fibers and soak again for 30 min. The process repeated up to 3 times. The diluted fibers are flattened physically and combs with a steel comb. To speed up dry process, the long wet fibers should placed in the oven at 30 °C temperature for 10 to 12 minutes where most of moisture can be removed. Then fibers are totally dried in outdoors, combined again, then finally cut to the necessary desired length of 5 cm and soak in oil about 15 to 20 minutes and dry in the sun light for 24 h [6]. 3.4. Water
3. Tests on materials
According to IS 456: 2000, Drinking water is suitable to mix the concrete. pH value of the water should not be less than 6.0.
3.1. Tests on cement Different tests are carried out on Cement for identification of properties (Table 2).
3.5. Chemical admixture Super Plasticizer conforming to IS 9103 used.
Table 1 The materials used in this work. S. No
Materials
01 02 03
Cement Fine Aggregate Coarse Aggregate
04 05 06
Coconut Fiber Water Admixture
Table 3 Shows property of fine aggregates. Ppc M Sand Aggregates which are passes through 20 mm IS sieve. Washed Fiber Length of 5 cm Drinking Water Rheobuild 918
S. No
Property
Values obtained
Limit as per I.S 2386
01 02 03
Specific Gravity Bulk Density Fineness Modulus
2.78 1.69 (gram/cc) 2.184
2.60–2.80 1.20–1.8 (g/cc) 2.2 to 2.6 Fine sand 2.6 to2.9 Medium sand 2.9 to 3.2 Coarse sand
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
3
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
4. Experimental procedure The following are the Mix Proportion obtained from using IS 10262:2009 for the design of concrete mix (Table 4).
4.1. Concrete mixing All moulds were cleaned and lubricated properly for casting. Make sure that it was a safe tightening for correct the dimensions before cast specimens. Proper care is taken whether, there were no remaining gaps and there is no possibility to slurry leakages. The exact procedure is adopted in process of mixing and casting [7] (Fig. 1). Cement and Fine aggregates are mixed completely upto certain uniform mixture obtained (Fig. 2). The approved fiber quantities are 4%, 5% and 6% of cement. The coconut fiber strips are cut 5 cm long washed, covered with coconut oil in proper way and dried in sun-light about 24 h (Fig. 3). Then added to mixture upto a certain uniform colour was obtained. Then, Coarse aggregates are added to the same mixture and follows with addition of water. Caring must taken for slowly adding water in certain stages, to prevent the bleeding (Fig. 4). It effects the formation of a concrete height force of water needed to moisturise the surface. The adhesive adds in final stage of adding water to save enough time for mixing, before concrete get hardening stage. It places in mould, compressed and completed as shown in Fig. 5. Cubes of each proportions are prepared with processed fibers also. Compression strength is determined after seven days and twenty eight days curing [7]. Calculated amounts of cement and fine aggregates are mixed completely until a steady state mixture obtained. 0.6% and 1.2% coconut fibers adopted are added to the total volume of coarse concrete aggregates to the same mixture and then added with Drinking water. Proper care is taken while adding water in stages for
Fig. 2. Finishing of moulds.
Table 4 Shows the number of samples required for testing.
Fig. 3. Coconut fiber strands.
S. No
Plain concrete
0.6% of fiber
1.2% of fiber
01 02 03 04 05 06
2 Cubes 1 Cylinder 1 Prism/Beam 1 Small Cylinder 600*600*50 mm slab 600*600*35 mm slab
2 Cubes 1 Cylinder 1 Prism/Beam 1 Small Cylinder 600*600*50 mm slab 600*600*35 mm slab
2 Cubes 1 Cylinder 1 Prism/Beam 1Small Cylinder 600*600*50 mm slab 600*600*35 mm slab
preventing bleeding which results the formation of a concrete height force of water needs to moisturize the surface (Fig. 6). The adhesive is added to final stage while adding water to save sufficient time for mixing before, concrete gets hardening stage and placed in mould and pressed (Fig. 7). Six cubes of each one is prepared and processed. The compression strength is determined for seven days and twenty eight days [8]. 5. Result analysis 5.1. Slump test on concrete The above table it observe that, desire slump value obtain by, Trial-III at water cement ratio of 0.50. Hence it is fixed as design ratio. Trial-I and II yields very less slump values because of inadequate paste available to binds the mix or improper mixing procedures (Table 5). 5.2. Compression strength of nominal concrete
Fig. 1. Mixing of concrete.
From above table, mean value from three readings is 24.97 N/ mm2. It taken as, compression strength of Nominal concrete (Table 6).
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
4
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
Fig. 4. Split tensile test specimens casting and testing.
Fig. 5. Slab specimen casting and curing process.
Fig. 6. Crack analysis of plain concrete 0.6% of coir fiber and 1.2% of coir fiber of 50 mm slabs.
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
5
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
Fig. 7. Impact load on cylinders.
5.4. Compressive strength results with raw coconut coir fiber reinforced concrete
Table 5 Slump test on trails. Trials
w/c ratio
Slump height (mm)
Remarks
Trial-I Trial-II Trial-III
0.42 0.45 0.5
30.2 51.6 121.2
Target Slump is not achieved. Target Slump is not achieved. Desired Slump height is obtained (Slump > 100 mm).
5.3. Compression strength results with processed coconut coir fiber reinforced concrete Reinforced concrete with coconut fiber is added to the concrete in varying proportion (0.6 and 1.2%) of this volume of concrete), with water cement rate of 0.50. Required stagnation value and compression strength nominal concrete were obtained at 0.5 ratio. However, while adding fiber to mix is observed low operability. Thus super plasticizers were added with different proportions to cement for obtaining a concrete mixture with suitable operability [9] (Table 7).
Reinforced concrete is poured with 0.5% coconut fiber in cement where the required stagnation values and compression strength is obtained for plain concrete. However, while adding fiber to the mix shows very low operability. Super plasticizers with different proportions of cement have been added to obtain concrete mix with suitable operability (Table 8). From the table, a descending trend is observed in the maximum compression strength when adding 4% fiber. When more fibers are added, much lower pressure resistance values are obtained than conventional concrete. It is due to the formation of a transition zone which creates weak area around the fibers make the entire sample weak [10]. 5.5. Split tensile test Split tensile test perform on standard cylinders with 15 cm diameter and 30 cm depth samples for both ordinary concrete, and reinforced concrete was poured with coconut fibers (raw and processed fibers) with varying proportions of fibers (1.2%, 0.6%).
Table 6 Compression strength results of nominal concrete. Number of specimens
w/c ratio
Slump height (mm)
7 days results (N/mm2)
28 days results (N/mm2)
1. 2. 3.
0.4 0.6 1.2
15 20 50
16.32 16.76 15.89
25.65 24.87 24.38
Table 7 Compression strength results of fiber reinforced concrete and slump test. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
Compression strength (N/mm2) 7 days
28 days
1. 2. 3.
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
15.22 17.49 17.21
24.74 26.06 25.86
Compression strength (N/mm2)
Table 8 Compression strength results of fiber reinforced concrete and slump results. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
1. 2. 3.
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
7 days
28 days
11.2 12.52 9.60
10.50 11.93 8.32
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
6
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
Table 9 Split tensile strength results of processed fiber reinforced concrete and slump results. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
Split tensile strength (N/mm2)
1. 2. 3. Average = 4.17
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
1.40 1.32 1.45
Table 10 Flexural strength results of raw coconut coir fiber on concrete beams. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
Flexural strength (N/mm2)
1. 2. 3. Average = 4.39
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
4.462 4.43 4.30
Table 11 Impact test values of slabs. S. NO
Type of slab
1. Plain Concrete 2. Plain Concrete 3. 0.6% Fiber 4. 0.6% Fiber 5. 1.2% Fiber 6. 1.2% Fiber Total Average = 212.5 kN/m2
Dimensions
Height of hammer
no. of blows
Strength
50 mm 35 mm 50 mm 35 mm 50 mm 35 mm
750 mm 750 mm 750 mm 750 mm 750 mm 750 mm
3 1 4 2 5 2
225 kN/m2 75 kN/m2 300 kN/m2 150 kN/m2 375 kN/m2 150 kN/m2
In each case the 28-day power values are obtain by loading under the pressure testing machine (Table 9). 5.6. Flexural strength Bending strength test is perform on standard beams of Size, 15 cm 15 cm 70 cm. Samples of cement reinforced concrete were poured with coconut fibers with varying proportions of fibers (4%, 5% and 6%). In each case, 28 days strength values are obtain at a rate of loading under, the device for bending strength. Bending strength of nominal concrete beams at a ratio of 0.4 w/c with a slump value of 15 mm, and a power of 28 days is 12 N/mm2 (Table 10). 5.7. Impact test on slabs After 28 days of curing, slab should be cleaned with dry cloth to remove dust particles present in it. Next it is placed on the even surface for impact testing. Now take the steel ball and place it at the centre of the slab. On the steel ball the hammer rod of 10kgs should be placed for the application of load on slab. Load should be applied gradually and the number of blows has to be noted down. Repeat the same procedure for the remaining slabs of all plain concreteslabs of fiber content of both 0.6% and 1.2%. Thus this is how the impact test is conducted on slabs (Table 11). Determination of impact strength of the slabs on both plain concrete and concrete with fiber percentage in it. 5.8. Standard proctor test The test is conducted as per IS code 2720, Dimension of Cylinder: (300 mm * 65 mm), Weight of hammer: 10 kg used. Height of hammer: 750 mm, Steel ball, supporting cubes are used while conducting test. No of blows for plain concrete = 120 blows, No
blows Blows Blows Blows Blows Blows
of blows to the 0.6% of fiber content = 132 blows, No of blows for 1.2% of fiber = 110 blows. Results: Strength for 28 days Plain concrete = 9 kN/m2, 0.6% of coir = 9.9 kN/m2, 1.2% of coir = 8.25 kN/m2 6. Conclusion The main conclusions of this study are 1. When adding 0.6% coconut and 1.2% coconut with aqueous water cement ratio of 0.40. The compression strength test yields the good results. However, compression strength decreases while adding of other fibers. It should be due to the fact that, when fibers are adds in initial stage of concrete, fine micro processes enter the surface pores in fibers resulting in better bond between fibers and the mix. But another addition of the fibers leads to the formation of the fiber mass in mix which will leads to a decrement in Connectivity. Thus, there is an ideal value to fiber cement ratio after compression strength decreases. Thus, 0.40 value is taken as ideal water cement ratio and the optimal fiber content ratio is 0.6% and 1.2%. 2. When the fiber content is increased, the tensile split strength increases at maximum of 5%. When fiber content increases after this value, a decrement in tensile stress is observed. It is due, to the fact of tensile failures occur because of disturbance of atoms and molecules presence in concrete. While adding fibers they act as a bond that binds them together. 3. The fiber content increases then, there is an increment in flexion strength with a maximum 5% of fiber. 4. Decrease in compression strength is observes in concrete with mesh fibers. It is due to formation of a weak transition zone around these fibers, it makes total sample weak. Moreover, thickness of fibers hinder the best packaging of concrete components make it as weak. Dust particles presence and other
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
impurities on its surface of fibers also another reason to decrease the strength. It must interfere with combination of mixture and ensure the strength formations. 5. Tensile properties of CCFC crack pattern shows, it is especially useful in construction activities at seismic areas due to its high tensile and post peak load behavior provide proper caution to the population before the structure reaches complete collapse stage. 6. Due to high relative strength, it is a good alternative to asbestos fibers in roof sheets. Which are a natural origin that does not produce a threat to the environment. 7. Scope of the future Impact of coconut fibers in high strength concrete shall be studied. The use of CFCs extends to industrial and commercial buildings. Corrosion studies was not carried out on CCFC and its applicability in construction also tested. Coconut fiber is good insulator with itself. Therefore, it improve thermal properties of concrete especially, useful in tropical country like india. Where, mercury levels are high for most parts of year. In order to maintain room temperature with in the comfort levels of its in habitants. It reduces the load on air condition system and thus reduce energy consumptions. CRediT authorship contribution statement Habibunnisa Syed: Investigation, Methodology, Funding acquisition, Project administration, Writing - original draft, Writing review & editing. Ruben Nerella: Conceptualization, Data curation,
7
Formal analysis, Funding acquisition. Sri Rama Chand Madduru: Resources, Software, Supervision, Validation, Visualization. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] M. Ardanuy, J. Claramunt, R.D. Toledo Filho, Cellulosic fiber reinforced cementbased composites: a review of recent research, Constr. Build. Mater. 79 (2015) 115–128. [2] N. Stevulova, V. Hospodarova, Cellulose fibres used in building materials, in: Proceedings of REHVA Annual Conference Advanced HVAC and Natural Gas Technologies, pp. 211, June 2015. [3] Marie-Therese Wisniowski, Cellulosic fibers (natural)- cotton art resource, in: Cellulosic Fibers Natural Cotton, pp.1–9, 2014. [4] Oh-Heon Kwon et al., The stress analysis and the crack behaviour according to the characteristic of the interfacial region in fiber reinforced mmc, Int. J. Modern Phys. B (2012). [5] A. Ticoalu, T. Aravinthan, F. Cardona, A review of current development in natural fiber composites for structural and infrastructure applications, in: Southern Region Engineering Conference, SREC2010-F1-5, pp.1–6, 2010. [6] D. Sedan, C. Pagnoux, A. Smith, T. Chotard, Mechanical properties of hemp fiber reinforced cement: Influence of the fibre/matrix interaction, J. Eur. Cer. Soc. 28 (1) (2008) 183–192. [7] M.A. Ismail, Compressive and tensile strength of natural fiber reinforced cement base composites, AI_Rafidian Eng. J. 15 (2) (2007) 42–51. [8] Z. Li, L. Wang, X. Wang, Flexural characteristics of coir fiber reinforced cementitious composites, Fibers Polym. 7 (3) (2006) 286–294. [9] J.M.L. Reis, Fracture and flexural characterization of natural fiber-reinforced polymer concrete, Constr. Build. Mater. 20 (9) (2006) 673–678. [10] Sidney Diamond, The microstructure of cement paste and concrete - a visual primer, Cem. Concr. Compos. 26 (2004) 919–933.
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Role of coconut coir fiber in concrete Habibunnisa Syed a,⇑, Ruben Nerella a, Sri Rama Chand Madduru b a b
Department of Civil Engineering, Vignan’s Foundation for Science, Technology & Research (Deemed to be University), Vadlamudi, Guntur, Andhra Pradesh 522213, India Department of Civil Engineering, Sri Chaitanya Engineering College, Karimnagar, Telangana, India
a r t i c l e
i n f o
Article history: Received 7 December 2019 Received in revised form 23 January 2020 Accepted 25 January 2020 Available online xxxx Keywords: Coconut coir fiber reinforced concrete Compressive strength Fiber mesh Tensile strength Flexural strength Slump test
a b s t r a c t Now a days the cost of construction increases along with gradual effect on the environment and it has led the researchers to the acceptance of natural fibers such as coconut fibers for improving the strength in concrete. Coconut fibers that are abundantly accessible at the test site making it relatively applicable as a reinforcing material in concrete. Concrete with different fiber contents was evaluated with conventional concrete or prestressed concrete and different strengths parameters such as bending, compression and tensile strength of coconut fiber varies with a proportions (0.6% and 1.2%) of total weight of the volume of concrete coconut fiber is carried out. The effect of fiber shape on strength property studied by testing with coconut fiber mesh from pre-defined dimension. The optimum percentage of both treated fiber yarn and raw fiber nets was found with trial and error process and maximum percentage of super plasticizer needed to both ordinary cement as well as coconut fibers in the concrete for basic operability was also determined. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the First International conference on Advanced Lightweight Materials and Structures.
1. Introduction Fiber-like thread and material that is useful to various purposes. The fibers produces from plants (vegetables, wood, leaves), geological processes and animals are known as natural fibers [1]. The researchers uses natural plant fibers as a substitute material in steel and/or synthetic fibers for use in compounds(cement paste, cement mortar and/or concrete) to improve their strength properties [1]. These plant fibers are referred to as natural fibers, containing coconut fibers, sisal, jute, carp and cannabis, eucalyptus grandis, malva, ramie past, pineapple leaves, cannabis, aspheric leaves, abaca leaves, jaws, dates, bamboo, banana, palm, hemp And linen, cotton and sugar cane. Natural fibers are inexpensive and available in most of the countries. Therefore, their usage in building materials for properties of mounting compounds costs very little. The added benefit may also includes ease of use/easy to handle the fibers due to its flexible nature. The problem arises, when a high percentages of fiber used in steel fibers. But to use very high fiber content, a methodology for pouring is needed [2]. Fracture fragment and fiber content are terms used to express fiber quantities in a given compound. Reinforced compounds can be ⇑ Corresponding author. E-mail address: [email protected] (H. Syed).
used for many civil engineering applications including corrugated roof tiles, tiles, simple slabs, tiles and mortars [2].
1.1. Characteristics of coconut fiber Coconut fibers with strength of 21.51 MPa are strongest one among all natural fibers. It is able to take strains 4 to 6 times higher than other fibers [3]. Coconut fibers has examined by many researchers to various purposes. There are significant variations some of characteristics are, for example the diameter of the coconut fibers is almost identical and the amounts of tensile strength are relatively different, for example the fibroblasts of different individual cells were depends on type of plant, its location and puberty [3]. Elasticity and rupture of fibers was effected by length to diameter ratio of fibers it also determine the product from which they are manufactured. Shape and size of hollow central cavity. The cavity depend upon (1) Thickness of cell wall (2) Source of fibers. Hollow cavity, acts as a acoustic and thermal insulation due to existence reduces bulk density of fibers [3]. Coconut fiber contains cellulose, cellulose sugar and lignin as a main composition. These formulations effects dissimilar properties in coconut fibers [3]. Pre-treatment of fibers led to a change in composition and ultimate changes occur due to their properties and also their properties of composite materials. Sometimes it
https://doi.org/10.1016/j.matpr.2020.01.477 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the First International conference on Advanced Lightweight Materials and Structures.
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
2
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
improve behaviour of fibers. But, Sometimes it effect was unfavourable [4]. 2. Materials These are the following materials used in the manufacturing of concrete (Table 1). They are
Table 2 Cement properties. S. No
Property
Values obtained
Limit as per I.S 4031
01
Initial Setting time, Final Setting time Soundness Density Fineness Initial Setting time, Final Setting time
71 min, 300 min
>30
1 mm 3.099 g/cc 7.2% 71 min, 300 min
<10 mm 3.16 <10.01% >30
02 03 04 05
2.1. Cement Portland Pozzolana Cement produced by grinding together portland cement clinker and pozzolana with addition of gypsum or calcium sulphate or by intimately and uniformly blending portland cement and fine pozzolana. Calcined clay or fly ash is used for manufacture of PPC. It produce less heat of hydration and also reduces leaching of calcium hydroxide liberated during the setting and hydration of cement. 2.2. Coarse aggregate and fine aggregate Aggregates are the important material in concrete. They give body to the concrete, reduce shrinkage and effect economy. Aggregates Classified into fine aggregates and coarse aggregates. Aggregates most of which retained on I.S sieve 4.75 mm are Coarse aggregates, which passes through 4.75 mm known as fine aggregates. In this work manufactured sand and crushed aggregates passes through 20 mm I.S sieve are used as fine aggregate coarse aggregates respectively. 2.3. Coconut fiber Raw coconut fiber and processed coconut fiber both are used in this work. Treatment of fibers removes dust and other particles left on fiber so as to augment the surface of contact between fiber and mix resulting in better binding between reinforcement and concrete results ultimate high strength [5]. 2.4. Water According to I.S 456:2000, water used for mixing and curing shall be clean and free from injuries amounts of oils, acids, alkalis, salts, sugar and organic materials or any other substances that may detorious to concrete and steel. pH value of water used for mixing the concrete shall be less than 6.
3.2. Aggregate tests Aggregate is a vital component in concrete. It occupies 70% to 80% of volume of concrete. Its impact on the properties and characteristics of different concrete. Following tests performed on aggregates for determination different properties. 1. Specific gravity test on coarse aggregates. 2. Bulk density test on coarse aggregates. 3. Sieve analysis on coarse aggregates [5]. Standard I.S sieves are used for sieve analysis process of fine aggregates. As per I.S 2386, Bulk density lies between 1.2 and 1.8 g/cc and Specific gravity lies between 2.60 and 2.80 (Table 3). 3.3. Processed coconut fibers Only processed coconut fiber is used in this research. They are appropriately washed and tied into yarns before usage. Fiber processing remove dust and residual particles remaining on fibers to increases contact surface between fibers and the mix results in improved bonding between reinforcement, concrete and ultimate higher strength. Fibers are washes in running tap water for about 30 min to lose fibers and to remove coconut dust. After wash the fibers and soak again for 30 min. The process repeated up to 3 times. The diluted fibers are flattened physically and combs with a steel comb. To speed up dry process, the long wet fibers should placed in the oven at 30 °C temperature for 10 to 12 minutes where most of moisture can be removed. Then fibers are totally dried in outdoors, combined again, then finally cut to the necessary desired length of 5 cm and soak in oil about 15 to 20 minutes and dry in the sun light for 24 h [6]. 3.4. Water
3. Tests on materials
According to IS 456: 2000, Drinking water is suitable to mix the concrete. pH value of the water should not be less than 6.0.
3.1. Tests on cement Different tests are carried out on Cement for identification of properties (Table 2).
3.5. Chemical admixture Super Plasticizer conforming to IS 9103 used.
Table 1 The materials used in this work. S. No
Materials
01 02 03
Cement Fine Aggregate Coarse Aggregate
04 05 06
Coconut Fiber Water Admixture
Table 3 Shows property of fine aggregates. Ppc M Sand Aggregates which are passes through 20 mm IS sieve. Washed Fiber Length of 5 cm Drinking Water Rheobuild 918
S. No
Property
Values obtained
Limit as per I.S 2386
01 02 03
Specific Gravity Bulk Density Fineness Modulus
2.78 1.69 (gram/cc) 2.184
2.60–2.80 1.20–1.8 (g/cc) 2.2 to 2.6 Fine sand 2.6 to2.9 Medium sand 2.9 to 3.2 Coarse sand
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
3
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
4. Experimental procedure The following are the Mix Proportion obtained from using IS 10262:2009 for the design of concrete mix (Table 4).
4.1. Concrete mixing All moulds were cleaned and lubricated properly for casting. Make sure that it was a safe tightening for correct the dimensions before cast specimens. Proper care is taken whether, there were no remaining gaps and there is no possibility to slurry leakages. The exact procedure is adopted in process of mixing and casting [7] (Fig. 1). Cement and Fine aggregates are mixed completely upto certain uniform mixture obtained (Fig. 2). The approved fiber quantities are 4%, 5% and 6% of cement. The coconut fiber strips are cut 5 cm long washed, covered with coconut oil in proper way and dried in sun-light about 24 h (Fig. 3). Then added to mixture upto a certain uniform colour was obtained. Then, Coarse aggregates are added to the same mixture and follows with addition of water. Caring must taken for slowly adding water in certain stages, to prevent the bleeding (Fig. 4). It effects the formation of a concrete height force of water needed to moisturise the surface. The adhesive adds in final stage of adding water to save enough time for mixing, before concrete get hardening stage. It places in mould, compressed and completed as shown in Fig. 5. Cubes of each proportions are prepared with processed fibers also. Compression strength is determined after seven days and twenty eight days curing [7]. Calculated amounts of cement and fine aggregates are mixed completely until a steady state mixture obtained. 0.6% and 1.2% coconut fibers adopted are added to the total volume of coarse concrete aggregates to the same mixture and then added with Drinking water. Proper care is taken while adding water in stages for
Fig. 2. Finishing of moulds.
Table 4 Shows the number of samples required for testing.
Fig. 3. Coconut fiber strands.
S. No
Plain concrete
0.6% of fiber
1.2% of fiber
01 02 03 04 05 06
2 Cubes 1 Cylinder 1 Prism/Beam 1 Small Cylinder 600*600*50 mm slab 600*600*35 mm slab
2 Cubes 1 Cylinder 1 Prism/Beam 1 Small Cylinder 600*600*50 mm slab 600*600*35 mm slab
2 Cubes 1 Cylinder 1 Prism/Beam 1Small Cylinder 600*600*50 mm slab 600*600*35 mm slab
preventing bleeding which results the formation of a concrete height force of water needs to moisturize the surface (Fig. 6). The adhesive is added to final stage while adding water to save sufficient time for mixing before, concrete gets hardening stage and placed in mould and pressed (Fig. 7). Six cubes of each one is prepared and processed. The compression strength is determined for seven days and twenty eight days [8]. 5. Result analysis 5.1. Slump test on concrete The above table it observe that, desire slump value obtain by, Trial-III at water cement ratio of 0.50. Hence it is fixed as design ratio. Trial-I and II yields very less slump values because of inadequate paste available to binds the mix or improper mixing procedures (Table 5). 5.2. Compression strength of nominal concrete
Fig. 1. Mixing of concrete.
From above table, mean value from three readings is 24.97 N/ mm2. It taken as, compression strength of Nominal concrete (Table 6).
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
4
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
Fig. 4. Split tensile test specimens casting and testing.
Fig. 5. Slab specimen casting and curing process.
Fig. 6. Crack analysis of plain concrete 0.6% of coir fiber and 1.2% of coir fiber of 50 mm slabs.
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
5
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
Fig. 7. Impact load on cylinders.
5.4. Compressive strength results with raw coconut coir fiber reinforced concrete
Table 5 Slump test on trails. Trials
w/c ratio
Slump height (mm)
Remarks
Trial-I Trial-II Trial-III
0.42 0.45 0.5
30.2 51.6 121.2
Target Slump is not achieved. Target Slump is not achieved. Desired Slump height is obtained (Slump > 100 mm).
5.3. Compression strength results with processed coconut coir fiber reinforced concrete Reinforced concrete with coconut fiber is added to the concrete in varying proportion (0.6 and 1.2%) of this volume of concrete), with water cement rate of 0.50. Required stagnation value and compression strength nominal concrete were obtained at 0.5 ratio. However, while adding fiber to mix is observed low operability. Thus super plasticizers were added with different proportions to cement for obtaining a concrete mixture with suitable operability [9] (Table 7).
Reinforced concrete is poured with 0.5% coconut fiber in cement where the required stagnation values and compression strength is obtained for plain concrete. However, while adding fiber to the mix shows very low operability. Super plasticizers with different proportions of cement have been added to obtain concrete mix with suitable operability (Table 8). From the table, a descending trend is observed in the maximum compression strength when adding 4% fiber. When more fibers are added, much lower pressure resistance values are obtained than conventional concrete. It is due to the formation of a transition zone which creates weak area around the fibers make the entire sample weak [10]. 5.5. Split tensile test Split tensile test perform on standard cylinders with 15 cm diameter and 30 cm depth samples for both ordinary concrete, and reinforced concrete was poured with coconut fibers (raw and processed fibers) with varying proportions of fibers (1.2%, 0.6%).
Table 6 Compression strength results of nominal concrete. Number of specimens
w/c ratio
Slump height (mm)
7 days results (N/mm2)
28 days results (N/mm2)
1. 2. 3.
0.4 0.6 1.2
15 20 50
16.32 16.76 15.89
25.65 24.87 24.38
Table 7 Compression strength results of fiber reinforced concrete and slump test. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
Compression strength (N/mm2) 7 days
28 days
1. 2. 3.
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
15.22 17.49 17.21
24.74 26.06 25.86
Compression strength (N/mm2)
Table 8 Compression strength results of fiber reinforced concrete and slump results. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
1. 2. 3.
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
7 days
28 days
11.2 12.52 9.60
10.50 11.93 8.32
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
6
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
Table 9 Split tensile strength results of processed fiber reinforced concrete and slump results. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
Split tensile strength (N/mm2)
1. 2. 3. Average = 4.17
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
1.40 1.32 1.45
Table 10 Flexural strength results of raw coconut coir fiber on concrete beams. Number of specimens
w/c ratio
Adding % of coconut fiber
Quantity of super plasticizer used (ml)
Slump test result (mm)
Flexural strength (N/mm2)
1. 2. 3. Average = 4.39
0.4 0.6 1.2
0% 0.6% 1.2%
75 195 370
15 20 50
4.462 4.43 4.30
Table 11 Impact test values of slabs. S. NO
Type of slab
1. Plain Concrete 2. Plain Concrete 3. 0.6% Fiber 4. 0.6% Fiber 5. 1.2% Fiber 6. 1.2% Fiber Total Average = 212.5 kN/m2
Dimensions
Height of hammer
no. of blows
Strength
50 mm 35 mm 50 mm 35 mm 50 mm 35 mm
750 mm 750 mm 750 mm 750 mm 750 mm 750 mm
3 1 4 2 5 2
225 kN/m2 75 kN/m2 300 kN/m2 150 kN/m2 375 kN/m2 150 kN/m2
In each case the 28-day power values are obtain by loading under the pressure testing machine (Table 9). 5.6. Flexural strength Bending strength test is perform on standard beams of Size, 15 cm 15 cm 70 cm. Samples of cement reinforced concrete were poured with coconut fibers with varying proportions of fibers (4%, 5% and 6%). In each case, 28 days strength values are obtain at a rate of loading under, the device for bending strength. Bending strength of nominal concrete beams at a ratio of 0.4 w/c with a slump value of 15 mm, and a power of 28 days is 12 N/mm2 (Table 10). 5.7. Impact test on slabs After 28 days of curing, slab should be cleaned with dry cloth to remove dust particles present in it. Next it is placed on the even surface for impact testing. Now take the steel ball and place it at the centre of the slab. On the steel ball the hammer rod of 10kgs should be placed for the application of load on slab. Load should be applied gradually and the number of blows has to be noted down. Repeat the same procedure for the remaining slabs of all plain concreteslabs of fiber content of both 0.6% and 1.2%. Thus this is how the impact test is conducted on slabs (Table 11). Determination of impact strength of the slabs on both plain concrete and concrete with fiber percentage in it. 5.8. Standard proctor test The test is conducted as per IS code 2720, Dimension of Cylinder: (300 mm * 65 mm), Weight of hammer: 10 kg used. Height of hammer: 750 mm, Steel ball, supporting cubes are used while conducting test. No of blows for plain concrete = 120 blows, No
blows Blows Blows Blows Blows Blows
of blows to the 0.6% of fiber content = 132 blows, No of blows for 1.2% of fiber = 110 blows. Results: Strength for 28 days Plain concrete = 9 kN/m2, 0.6% of coir = 9.9 kN/m2, 1.2% of coir = 8.25 kN/m2 6. Conclusion The main conclusions of this study are 1. When adding 0.6% coconut and 1.2% coconut with aqueous water cement ratio of 0.40. The compression strength test yields the good results. However, compression strength decreases while adding of other fibers. It should be due to the fact that, when fibers are adds in initial stage of concrete, fine micro processes enter the surface pores in fibers resulting in better bond between fibers and the mix. But another addition of the fibers leads to the formation of the fiber mass in mix which will leads to a decrement in Connectivity. Thus, there is an ideal value to fiber cement ratio after compression strength decreases. Thus, 0.40 value is taken as ideal water cement ratio and the optimal fiber content ratio is 0.6% and 1.2%. 2. When the fiber content is increased, the tensile split strength increases at maximum of 5%. When fiber content increases after this value, a decrement in tensile stress is observed. It is due, to the fact of tensile failures occur because of disturbance of atoms and molecules presence in concrete. While adding fibers they act as a bond that binds them together. 3. The fiber content increases then, there is an increment in flexion strength with a maximum 5% of fiber. 4. Decrease in compression strength is observes in concrete with mesh fibers. It is due to formation of a weak transition zone around these fibers, it makes total sample weak. Moreover, thickness of fibers hinder the best packaging of concrete components make it as weak. Dust particles presence and other
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477
H. Syed et al. / Materials Today: Proceedings xxx (xxxx) xxx
impurities on its surface of fibers also another reason to decrease the strength. It must interfere with combination of mixture and ensure the strength formations. 5. Tensile properties of CCFC crack pattern shows, it is especially useful in construction activities at seismic areas due to its high tensile and post peak load behavior provide proper caution to the population before the structure reaches complete collapse stage. 6. Due to high relative strength, it is a good alternative to asbestos fibers in roof sheets. Which are a natural origin that does not produce a threat to the environment. 7. Scope of the future Impact of coconut fibers in high strength concrete shall be studied. The use of CFCs extends to industrial and commercial buildings. Corrosion studies was not carried out on CCFC and its applicability in construction also tested. Coconut fiber is good insulator with itself. Therefore, it improve thermal properties of concrete especially, useful in tropical country like india. Where, mercury levels are high for most parts of year. In order to maintain room temperature with in the comfort levels of its in habitants. It reduces the load on air condition system and thus reduce energy consumptions. CRediT authorship contribution statement Habibunnisa Syed: Investigation, Methodology, Funding acquisition, Project administration, Writing - original draft, Writing review & editing. Ruben Nerella: Conceptualization, Data curation,
7
Formal analysis, Funding acquisition. Sri Rama Chand Madduru: Resources, Software, Supervision, Validation, Visualization. Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References [1] M. Ardanuy, J. Claramunt, R.D. Toledo Filho, Cellulosic fiber reinforced cementbased composites: a review of recent research, Constr. Build. Mater. 79 (2015) 115–128. [2] N. Stevulova, V. Hospodarova, Cellulose fibres used in building materials, in: Proceedings of REHVA Annual Conference Advanced HVAC and Natural Gas Technologies, pp. 211, June 2015. [3] Marie-Therese Wisniowski, Cellulosic fibers (natural)- cotton art resource, in: Cellulosic Fibers Natural Cotton, pp.1–9, 2014. [4] Oh-Heon Kwon et al., The stress analysis and the crack behaviour according to the characteristic of the interfacial region in fiber reinforced mmc, Int. J. Modern Phys. B (2012). [5] A. Ticoalu, T. Aravinthan, F. Cardona, A review of current development in natural fiber composites for structural and infrastructure applications, in: Southern Region Engineering Conference, SREC2010-F1-5, pp.1–6, 2010. [6] D. Sedan, C. Pagnoux, A. Smith, T. Chotard, Mechanical properties of hemp fiber reinforced cement: Influence of the fibre/matrix interaction, J. Eur. Cer. Soc. 28 (1) (2008) 183–192. [7] M.A. Ismail, Compressive and tensile strength of natural fiber reinforced cement base composites, AI_Rafidian Eng. J. 15 (2) (2007) 42–51. [8] Z. Li, L. Wang, X. Wang, Flexural characteristics of coir fiber reinforced cementitious composites, Fibers Polym. 7 (3) (2006) 286–294. [9] J.M.L. Reis, Fracture and flexural characterization of natural fiber-reinforced polymer concrete, Constr. Build. Mater. 20 (9) (2006) 673–678. [10] Sidney Diamond, The microstructure of cement paste and concrete - a visual primer, Cem. Concr. Compos. 26 (2004) 919–933.
Please cite this article as: H. Syed, R. Nerella and S. R. C. Madduru, Role of coconut coir fiber in concrete, Materials Today: Proceedings, https://doi.org/ 10.1016/j.matpr.2020.01.477