- Email: [email protected]
Durability characteristics of binary blend high strength SCC
Construction and Building Materials 146 (2017) 1–8
Contents lists available at ScienceDirect
Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat
Technical note
Durability characteristics of binary blend high strength SCC S.S. Vivek, G. Dhinakaran ⇑ School of Civil Engineering, SASTRA University, Thanjavur, India
a r t i c l e
i n f o
Article history: Received 3 January 2017 Received in revised form 27 March 2017 Accepted 7 April 2017
Keywords: Self compacting concrete Durability GGBFS Metakaolin Silica fume
a b s t r a c t SCC has emerged as an inevitable option in situations where there is scarcity of skilled labour at construction sites. In the present paper an attempt was made to produce SCC with three different supplementary cementitious materials as a partial substitute to cement in binary blend. Cement was replaced with ground granulated blast furnace slag (GGBFS) (25%, 50% & 75%), Metakaolin (MK) (10%, 20% & 30%) and Silica Fume (SF) (5%, 10% & 15%) respectively. Durability studies such as resistance against acid attack, sulphate attack, water absorption and sorptivity were done to evaluate the suitability of mineral admixtures. Experimental results of binary blend SCC were compared with concrete (NVC) to understand the effect of mineral admixtures. The results indicated low water absorption and lesser volume of permeable voids in MK based SCC compared to NVC. GGBFS based SCC (with 50% Substitution) exhibited better resistance against acid attack than NVC. No significant difference in weight loss was observed for concrete immersed in Na2So4 solution. SF with 10% substitution and MK with 20% substitution gave good results compared to control SCC. Hence it is concluded that SCC could be produced with supplementary cementitious materials without compromising on durability. Ó 2017 Elsevier Ltd. All rights reserved.
1. Introduction The placement of concrete in different locations needs detailed studies on cause and effect relating to deterioration of concrete. In locations such as marine environment, underground, etc., there is severe durability problem by carbonation, sulphate, acid and chloride attack. To overcome the above problem, SCC is an obvious answer, since SCC has better flow, passing and filling ability compared to normal vibrated concrete. The SCC was developed by Okamura in Japan to overcome unskilled labour problem in the construction industry. Later SCC has been used in primary, repair and rehabilitation works in Switzerland and other countries. Self Compacting Concrete is a densely packed concrete having closer Interfacial Transition Zone (ITZ) compared to Normal Vibrated Concrete (NVC). Thus SCC is less porous as it forms a better C-SH gel by interlocking the aggregates and binder matrix. SCC has been made in three ways, namely, adding more powder content in the form of mineral admixtures, adding chemical admixtures in the form of Super Plasticizers and Viscosity Modifying Agents (VMA) or a combination of both. Hence in the present study, SCC with a combination of mineral and chemical admixtures has been formulated to study its durability properties. To maintain economy, cement was replaced by three different mineral admixtures ⇑ Corresponding author. E-mail address: [email protected] (G. Dhinakaran). http://dx.doi.org/10.1016/j.conbuildmat.2017.04.063 0950-0618/Ó 2017 Elsevier Ltd. All rights reserved.
as mentioned above. Since cement employed was Ordinary Portland Cement (OPC), pozzolanic activity developed due to mineral admixtures could be easily understood. Dinakar et al. [1] made a detailed experimental study on SCC with different mineral admixtures pertaining to mix design, strength characteristics and durability characteristics. In this research paper, replacement levels of 0%, 10%, 30%, 50%, 70% and 85% with fly ash for strength comparison with normal vibrated concrete. They found that concrete specimens after immersion in 3% H2SO4 solution experienced lesser weight loss with increasing fly ash content and consequently lower chloride permeability than normal concrete. Hence SCC exhibited better durability compared to NVC in terms of high permeable voids, water absorption and resistance to segregation. Watcharapong et al. [2] made an experimental investigation on strength and resistance to chloride for ternary blended SCC containing high volume fly ash (ranging from 40 to 70%) and silica fume (ranging from 0 to 10%). With the above ternary combination of two mineral admixtures, a target strength of more than 60 MPa was obtained. In respect of durability, volume of voids and water absorption was studied. It was found that the durability characteristics improved significantly due to fly ash in SCC. Dhiyaneshwaran et al. [3] made durability study using fly ash from 10% to 50%. It was found that concrete specimens after immersion in 10% Na2SO4 solution showed no weight loss for any period of time. The weight loss of concrete specimens after
2
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
immersion in 10% HCl solution increased with respect to time. 30% dosage of fly ash reduced water absorption. Halit [4] carried out research using Class C fly ash in high volume to obtain SCC durability characteristics. They found that incorporation of 60% FA and 10% SF in SCC had higher resistance to chloride and freez-thaw. The compressive strength of binary and ternary mix was better than control mix after freez-thaw. Hassan and Adnan [5] studied the influence of quaternary blend incorporating supplementary cementitious materials. Cement was replaced to an extent of 70%. It was inferred from the results that concrete with 10% SF gave better compressive strength but reduced workability. Use of fly ash improved the workability and later age strength. Efstratios et al. [6] made research work on SCC durability using MK as cement replacement at higher levels, which enhanced better resistance to chloride penetration. Both penetration and migration coefficients correlated well with strength for MK based SCC. Kannan and Ganesan [7] performed experiments to study durability of RHA and MK based SCC. MK was used up to 30% and RHA was used up to 40%. Durability properties improved with 30% MK compared to the control mix. In a ternary mix, 15% RHA and 15% MK were found to be optimum. Eleftherios et al. [8] investigated the behaviour of SCC utilizing ladle furnace slag with 600 to 1200 N/m3 and 0.7% fibre reinforcement. The authors concluded that ladle furnace slag inclusion showed better results in respect of durability. It also enhanced resistance to freez-thaw and chloride penetration. Her Yung and Wen Liang [9] used LCD glass as aggregate up to 30% in SCC and found that the rheological properties improved with higher magnitude of LCD glass as substitute. Resistance against corrosion due to sulphate was better in LCD glass based SCC. An optimum value of 30% was proposed from their work. Rahman et al. [10] made a study on SCC using RHA as filler with replacement levels of 0% to 40% by total cement mass along with blended fine aggregates. The concrete properties in fresh and hardened states as well as water absorption were studied. For a SCC mix with RHA at 8% to 12%, good correlation was observed between compression and tension. RHA, as a CRM in concrete was directly proportional to water absorption. It was worthy to note that good resistance to segregation of 0.04 –0.2% was obtained. Ali et al. [11] made an investigation on SCC replacing cement with natural zeolite NZ (0%, 10%, 15%, 20%, 25%, 30%). Fresh concrete properties such as flow ability, passing ability and stability criteria were satisfied as per EFNARC with NZ dosage ranging from 10% to 25%. It was concluded from RCPT and electrical resistivity tests that durability of SCC got enhanced by the addition of natural zeolite. Resistance to segregation also improved by the inclusion of natural zeolite up to 30%. Kosmas and Nikolaos [12] experimentally investigated the durability properties of normal strength SCC and their effect on RC structures. The results were compared with conventionally vibrated concrete. From the test results, penetration depth values were found to be low even at higher w/c ratios. Hence SCC exhibited better longevity compared to CVC. Vasusmitha and Srinivasa Rao [13] investigated the effect of different mineral admixtures on tension and permeation of high strength self compacting concrete. The results indicated that HSSCC exhibited lower chloride permeability on concrete, dense micro structure, higher bond and tensile strength, lower permeability to oxygen and lower plastic settlement. Antonios et al. [14] studied the durability properties of SCC and conventional concrete through sorptivity, porosity and chloride ion permeability tests. Silica fume inclusion in SCC imparts lower porosity, capillary absorption and chloride ion permeability in a shorter duration of 28 days. Dehwah [15] studied the effect of mineral admixtures on resistance to corrosion, permeation and chloride ion diffusion. The chlorination depth was moderate for QDP or FA but it was lower for SF
+ QDP. SCC with 8% quarry dust powder (w/p 0.38) or with 8% quarry dust powder +5% SF was found to perform well. Mehmet et al. [16] investigated the rheological and transport properties of SCC with mineral admixtures. They used marble powder, limestone filler and fly ash as mineral admixtures. It was found that higher replacement levels affect the rheological properties and the sorptivity of admixed SCC was better than control mix. Marble powder and limestone filler enhanced the properties of hardened SCC. The role of silica fume and Metakaolin on fresh concrete properties as well as compressive strength of SCC was studied by Vivek and Dhinakaran [17–19,37] and they found that mineral admixtures play a vital role in modifying the properties of SCC. Among the durability test, the most common tests are water absorption, sorptivity, permeability and exposure to aggressive environment was conducted by Dhinakaran et al. [29] on HPC using optimum GGBS 20%, Quartz powder 10% with addition of AEA and LWA respectively. Arash and Morteza [30] investigated on Roller Compacted Concrete using GGBFS 40% have reduced porosity, water absorption and permeability properties. Similarly many durability studies were performed in SCC also. Mohsen et al. [31] performed research on durability of SCC using marble and tile wastes subjected to sulphate attack. The sulphate resistance offered by those factory wastes in SCC was higher than ordinary vibrated concrete was concluded. Siad et al. [32] studied that addition of natural pozzolan have more benefit than fly ash on SCC against sodium sulphate attack. Silva and Brito [33] investigated that SCC could be prepared using fly ash and lime stone filler as binary and ternary mixes to obtain the porosity and microstructure. The results infer that SCC of ternary blend could be mostly favourable. Ramezanionpour et al. [34] reported that SCC could also be employed in developing precast concrete elements under 36 different types of steam curing. For which the compressive strength and permeability was studied and reveals that if the temperature exceeds 70 °C results in negative effect on durability. Gurpreet [35] made research on SCC using the iron slag as a partial replacement of fine aggregate in order to study the durability characteristics of SCC. Kanish [36] investigated on durability performance of SCC using RCA’s and Mineral admixtures. From the available literature, it was found that many research works were available on resistance of SCC to chloride ion penetration and SF and FA based SCC. Hence in the present research three types of mineral admixtures namely MK, SF and GGBFS was used to study the durability properties of binary blended SCC by conducting water absorption, acid resistance, alkaline resistance and sorptivity tests. The obtained results of SCC were compared with those of Normal Vibrated Concrete (NVC).
2. Materials and methods 2.1. Material properties For the experimental programme, the following materials used and tested according to standards as discussed below. ASTM Type I [20] cement was used in the present work. Fine aggregate used was natural river sand and coarse aggregate was crushed granite. The specific gravity of FA used was 2.60 and that CA used was 2.65. Coarse aggregate specific gravity was found out using wire basket method in accordance with ASTM C 127 [21]. The maximum size of coarse aggregate used in the present work was limited to 12.5 mm. Table 1 gives chemical compositions of cement and other binary mineral admixtures employed for SCC. The super plasticizer (2.3% weight of cement) used was sulphonated naphthalene formaldehyde based was employed. Viscosity modifying admixture (VMA) (0.15% of weight of cement) was used to reduce segregation and bleeding. The combination type of binary blended SCC was pre-
3
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8 Table 1 Chemical composition of cement and mineral admixtures. Component (%)
Cement
GGBFS
MK
SF
SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O SO3 LOI
21.78 6.56 4.13 60.12 2.08 0.36 0.42 2.16 2.39
33.1 16.6 0.6 34.8 8.0 0.2 0.5 0.4 0.3
52.56 44.10 0.45 0.28 0.2 0.25 0.2 0 0.85
93.55 0.56 0.17 1.13 0.75 0.14 1.05 1.01 1.16
pared by combining cement, aggregates, mineral and chemical admixtures with water to powder ratio of 0.4 (arrived from laboratory trials). The proportions of fine aggregate and coarse aggregate was adjusted from the conventional concrete mix in order to obtain the flow ability, passing and filling ability since these are mandatory for SCC mix. Table 2 give the details of materials utilized in the present research work. SF is obtained from silicon industry. As a pozzolanic mineral, when it is combined with super plasticizers that will enhance the mechanical properties in the range of 100–150 MPa. MK is refined kaolin clay which was calcined under controlled conditions, having high pozzolanic activity. MK develops increase in compressive strength, better surface finishes and reduce efflorescence. GGBS is a by-product obtained from the blast furnaces in the manufacturing process of iron or steel, enhances tensile strength, elastic modulus, superior surface finishes and caters the durability problem. The mineral admixtures when employed in mix composition the rheological properties of SCC will be improved. 2.2. Mix design The concrete mix proportioning was performed for concrete with a characteristic compressive strength of 60 MPa in accordance with ACI 211.1-91 [22]. For laboratory trials, initial mix proportion of 1:1.6:1.6 (Binder: Sand: CA) was exhibited with the water to binder ration maintained at 0.40 and by obtaining the flow properties, the final mix proportion was illustrated in Table 2. To develop a SCC mix, the key parameters include W/P ratio, dosage of super plasticizer and stabilizer, proportion of fine aggregate to coarse aggregate. Details of rheological properties of SCC developed were already published by the authors of the present research work and were available in literature [17]. 2.3. Methods The experimental programme was aimed at studying the durability characteristics of SCC using three different percentages of
GGBFS (25, 50, 75), SF (5, 10, 15) and MK (10, 20, 30) as a substitute for cement. All the tests for fresh concrete properties were conducted as per EFNARC guidelines for SCC and the details are available in [23]. Since sulphate attack is a prime factor which creates problems in concrete, leading to severe damages such as cracking, expansion and disintegration of concrete 1585 [24], the behaviour of SCC specimens subjected to acid attack was studied in the present work. To assess the behaviour of SCC in aggressive environment and to study the effect of sulphate attack on concrete, the specimens were subjected to curing in diluted H2SO4 acid, which the structures encounter frequently in industries. 1% H2SO4 acid was used in this work to observe the deterioration of concrete when cured in it. Severe durability problem occurs in marine environment due to chloride attack [25]. To simulate the effect of marine environment and to study their behaviour in an aggressive marine environment, 5% sodium chloride was used in this study for curing the concrete specimens. BS 1881 [26] guidelines were followed in casting the specimens meant for compressive strength and were tested in the designated period. Voids or pores in the prepared concrete were determined in accordance with ASTM C642 [27]. A short-term durability property called sorptivity of concrete was assessed in accordance with ASTM C1585 [28]. The details of experimental set-up for the above tests are given in Figs. 1 to 3. 3. Results and discussion 3.1. Effect of GGBFS on durability of SCC SCC made with GGBFS absorbs fewer amounts of water than control SCC and NVC. Among three different percentages of GGBFS used, SCC with 50% of GGBFS gave better results than the other two mixes. SCC with more than 50% of GGBFS as substitute to cement lead to more permeable voids due to its higher volume. Similar trend was followed in volume of voids also, since both are directly proportional. Volume of voids for SCC with 50% GGBFS was found to be less than NVC and control SCC. In sorptivity, water absorption and permeable pore test, GGBFS with 50% of cement replacement showed significant improvement compared to other two mixes. It was due to the fineness of the slag material as 50% in cement content caused better conglomeration of SCC GGBFS mix that improved resistance to capillary action. Hence the pores of the concrete micro structure was completely filled with the powder content namely slag causing water tight for capillary rise. For SCC specimens subjected to 28- and 56-days curing in H2SO4 solution, the deterioration of concrete was ascertained based on the percentage weight loss. Here GGBFS SCC with 75%
Table 2 Constituents of SCC mixes. Materials (kg/m3)
Cement GGBFS MK SF Water W/P FA CA SP VMA No. of Specimens cast
NVC
600 – – – 196 0.40 412 1113 – – 3 specimens
SCC
600 – – –
GGBFS
Metakaolin
Silica fume
25%
50%
75%
10%
20%
30%
5%
10%
15%
– 150 – –
– 300 – –
– 450 – –
– – 60 –
– – 120 –
– – 180 –
– – – 30
– – – 60
– – – 90
834 686 13.8 0.90 each for 28 days and 56 days in each mix (Total: 66 Nos.)
4
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
Fig. 1. Water absorption and voids tests in progress.
Fig. 2. Specimens (a) before (b) during (c) after exposure to H2SO4 solution.
Fig. 3. Specimens (a) before (b) during (c) after exposure to Na2SO4 solution.
cement replacement showed lesser weight loss compared to the other two mixes. In sulphate attack, there was no weight loss observed with the other mixes. In SCC, GGBFS could be used in the range of 50% to 75% where matters a lot (see Figs. 4 and 5). 3.2. Effect of MK on durability of SCC Metakaolin MK was used as replacement for cement in the range of 0% to 30% with an increment of 10% respectively. From the experimental results, MK could be used from 20% to 30%, since 20% MK showed better performance in respect of sorptivity and apparent density. SCC with 30% MK exhibited better resistance against water absorption, porosity and acid attack at 28 and
56 days. There was no weight loss in the context of sulphate attack, both at 28- and 56- days. The calcined clay content improved the durability of SCC with increase in%MK since it is highly pozzolanic in nature. The pozzolan caused slow strength gain at early ages but at later ages, durability and strength got improved appreciably. Since OPC was used, addition of MK influenced the pozzolanic nature in SCC. Hence higher replacement levels with MK could be used where the long-term durability is a concern. 3.3. Effect of SF on durability of SCC SCC with 10% SF performed well in respect of sorptivity. SCC with 5% SF was better in terms of water absorption and permeable
5
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
6.67
6.71
6.23
2.71
2.67
2.45
2.05
2.34
2.56
3
3.04
2.61
2.69
4
2.63
5
3.29
6
5.12
5.53
7
6.31
6.86
6.24
6.71
6.43
8
Value in Percentage
Volume of Voids (%)
8.08
Water Absorption (%) 9
2 1 0
Fig. 4. Effect of GGBFS, SF and MK on Water absorption and permeable pores.
5
15.47
17.81
18.1
9.7
9.44
9.91
13.42 8.32
9.81
15.23
17.16 9.41
6.67
3.73
6.45
10
8.7
15
9.58
20 10.19
Value in Percentage
25
Weight loss in H2SO4 [56 days]
18.47
22.6
27
24.45
Weight loss in H2SO4 [28 days] 30
0
Fig. 5. Effect of GGBFS, SF and MK on weight loss in acids.
pore space. SCC with 15% SF was better in respect of apparent density and resistance to acid attack at 28- and 56- days respectively. There was no weight loss after 28- and 56-days of curing in sulphate solution. Thus SF used should be restricted to 15% for a binary blended SCC since it has silica and ferrous (iron) content which would cause corrosion of embedded reinforcing bars under severe exposure conditions.
3.4. Comparison of NVC and SCC (without cement replacement) On comparing SCC with NVC, it was found that there was wide variation in the values of sorptivity test, water absorption test, permeable pore space, apparent density and acid resistance (immersion in 5% of H2SO4 solution) at 28- and 56-days. There was negligible weight loss for both NVC and SCC after immersion in 5% Na2SO4 solution for 28- and 56-days. In the above durability tests, NVC performed better than SCC (without cement replacement). This was mainly due to the mixture composition i.e. fines were higher than coarse aggregates and also significant effect of water powder ratio in SCC mix (refer Table 2). The influence of super plasticizer and VMA dosages also influence the durability of SCC. In overall study, in sorptivity test GGBFS 50%, in water absorption and permeable pore test MK30%, in apparent density MK20% obtained better results compared to other SCC mixes and NVC. Immersion of cube specimens in 5% of H2SO4 solution of various
mixes at 28 and 56 days, GGBFS 75% performed better compared to other SCC mixes and NVC. Similar results were obtained by Dinakar et al. [1] in respect of durability with fly ash inclusion in SCC. After immersion in 3% H2SO4 solution, the deterioration of fly ash based SCC decreased with increasing fly ash content. In the present work, after immersion in 5% H2SO4 solution, SCC with GGBFS 75% showed good correlation with similar studies on durability. The results obtained from Kannan and Ganesan [7] blended SCC with MK 30% performed better in respect of permeability and was in line with similar studies. After immersion in 5% Na2SO4 solution, there was no weight loss for any length of time and this was similar to the results of Dhiyaneshwaran et al. [3] but the percentage of Na2SO4 was different. 3.5. Compressive strength of concrete 3.5.1. After immersion in acid (H2SO4) solution For concrete specimens, after immersion in H2SO4 solution for 28- and 56- days the loss in compressive strength was determined as per ASTM standard. Fig. 6 shows the compressive strength obtained under different curing conditions for all the 11 mixes. The compressive strength (difference) closer to 5 MPa was obtained for SCC with SF 5% and 10% respectively at the age of 28 and 56 days. The remaining mixes exhibited reduced compressive strength (difference) in the range of minimum 2 MPa to maximum 6 MPa indicating that 50% of strength was lost in acid
6
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
Compressive Strength in Water Curing [28 days]
Compressive Strength in H2SO4 [28 days]
Compressiv Strength in MPa
Compressive Strength in H2SO4 [56 days] 180 160 140
50.5
51.4 42.5
120 52.6
54.5
44.5
51.8
48.7
62.5
65.2
62.58
20
59.08
56.00
46.2
41.6
44.8 32.4
38.8
51.4
50.8
36.7
46.5
44.6
55.38
51.56
60.06
58.1
55.3
47.5
60 40
47.2
43.9 43.4
100 80
47.8
0
Fig. 6. Compressive strength of admixed SCC cured under water and H2SO4 solution.
solution at the age of 56- days. When acid reacts with concrete, the interlocking between the cement matrix and aggregate as C-S-H gel was broken down. The specimens kept under acid curing exhibited white patches on their surfaces. Honeycombing was also noticed on their surfaces due to acid attack. 3.5.2. After immersion in base (Na2SO4) solution After normal water curing, the concrete specimens were cured in Na2SO4 solution for a period of 28- and 56-days. Fig. 7 shows compressive strength obtained under different curing conditions for all the 11 mixes. SCC with MK 30% exhibited a compressive strength (difference) of 10.76 MPa and 12.66 MPa after 28- and 56-days of sulphate curing in respect of 28 days of normal water curing. Whereas for other mixes, the compressive strength (difference) between normal and sulphate curing obtained was in the range of 24 MPa (37%) to 26 MPa (40%) at 28- and 56-days respectively. In some mixes namely the strength loss was nil even at the two different ages of curing in Na2SO4 solution. The surface texture of the specimen was not affected by curing in base solution. There was minor strength loss in NVC and other SCC specimens to the tune of 10% when cured in base solution. 3.6. Evaluation of sorptivity characteristics The resistance against capillary suction due to the effect of mineral admixtures in SCC was studied by conducting sorptivity test as per ASTM C1585-13. It was found that the sorption coefficient for
control SCC was 23% more than normal vibrated concrete. It could be due to higher degree of flowability of SCC. However, in the case of SCC with GGBFS (25% and 50%), the sorption coefficient was found to be less compared to normal SCC; even it was lesser than the normally vibrated concrete. For SCC with 75% GGBFS, the sorption coefficient was little bit higher than the NVC and less than the control SCC. When MK was added to the tune of 10%, the sorption coefficient was on par with control SCC and with higher replacement levels, it performed better. SCC with SF10% showed better results and the other two mixes exhibited higher sorption coefficients. The reason could be inadequate replacement level with SF. Among the three different admixtures used in the present work, SCC with GGBFS and MK performed better when compared to SCC with SF (Fig. 8). 4. Cost analysis In the present research paper cost analysis was done through an economy index. Economy index is the ratio between strength and cost. In many of the works cost of concrete production was taken as a major deciding factor, whereas here the economic feasibility was obtained with the ratio of strength and cost. Compressive strength at the age of 28 days and cost of materials as per present scenario was taken to arrive at an economy index. Optimum mix was obtained based on these criteria. The economy index arrived for various mixes are tabulated in the Table 3. SCC gave better economy index than NVC due to its higher compressive strength. For
Compressive Strength in Water Curing [28 days]
Compressive Strength in Na2SO4 [28 days]
Compressive Strength in Na2SO4 [56 days]
Compressiv Strength in MPa
200 180 160 140
54.5
55
56.7
54.6 52.8
120 100
43.8 57.5
59
58.2
80
58.5
51.2
20
62.5
65.2
62.58
59.08
56.00
51.3
46.2
45.8
52.6
54
58.5
60.06
58.1
51.8
38.9
45.8
60 40
45.7
55.38
40.8
51.56
0
Fig. 7. Compressive strength of admixed SCC cured under water and Na2SO4 solution.
51
55.3
7
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
2.3
2.7
2.8 1.9
2
2.4
2.00
1.8
1.9
2.40
2.6
2.6
2.80
2.1
Sorption Coefficient (in 10-2 mm/S1/2 )
3.20
1.60 1.20 0.80 0.40 0.00
Fig. 8. Effect of GGBFS, MK and SF on resistance against sorption.
Table 3 Calculation of economy index (per m3 of Concrete). Mix Description
NVC SCC GGBFS 25 GGBFS 50 GGBFS 75 MK 10 MK 20 MK 30 SF 5 SF 10 SF 15
Mass in kg Cement
Slag
MK
SF
FA
CA
600 600 450 300 150 540 480 420 570 540 510
0 0 150 300 450 0 0 0 0 0 0
0 0 0 0 0 60 120 180 0 0 0
0 0 0 0 0 0 0 0 30 60 90
412 412 412 412 412 412 412 412 412 412 412
1113 1113 1113 1113 1113 1113 1113 1113 1113 1113 1113
SCC with GGBFS, this index ranged from 0.87 to 2.27. Among three mix combinations, SCC with 50% GGBFS can be considered as an optimum due to its strength magnitude at par with characteristic compressive strength. In the case of MK based SCC, increase of MK from 10 to 20% increased the economic index and further increase of MK to 30% showed a reduction in this index. It can be due to reduction in strength. Hence SCC with 20% MK can be an optimal mix in that category by compromising strength to 8%, which is permissible in the field. In the case of SCC with SF, concrete with SF5 gave better results in terms of strength and SF10 also acceptable in terms of economy index. 5. Conclusions Following are the conclusions drawn from the experiments performed on binary blend self compacting concrete using GGBFS, SF and MK as mineral admixtures. Based on tests conducted in the laboratory for fresh concrete properties, water to powder ratio was ascertained as 0.4 and optimum dosages of super plasticizer & stabilizer as 2.3% and 0.15% by weight of cement. From durability studies, it was found that SCC with CRM’s performed better than NVC and SCC without CRM’s. In the formulation of binary blended SCC, in respect of durability, the following replacement levels could be suggested: U Cement replacement with GGBFS at 50% to 75% would result in a better durable SCC mix. U Cement replacement level with SF shall be restricted to 15% for ensuring durability at critical locations.
Total Cost/m3 (US $)
Comp. Strength (MPa)
Economy Index (Strength/Cost)
85.58 85.58 71.73 57.88 24.63 87.42 89.27 91.11 88.35 92.04 95.27
62.50 65.20 62.58 59.08 56.00 46.20 55.38 51.36 60.06 58.10 55.30
0.73 0.76 0.87 1.02 2.27 0.53 0.62 0.56 0.68 0.63 0.58
U MK could be used in SCC at 20% to 30% as CRM. The percentage weight loss after immersion in 5% H2SO4 solution at 28 and 56 days was found to be lower for SCC with 75% GGBFS, 15%SF and 30%MK inferring that higher replacement levels were beneficial. The percentage weight loss was zero for all 11 mixes after immersion in 5% Na2SO4 solution at 28 and 56 days curing. SCC with 50% GGBFS, 20% MK and 10% SF exposed to sulphuric acid exhibited greater strength among the nine different mixes used. Similar trend was observed for SCC mixes exposed to sodium sulphate solution also. SCC with SF 10% exhibited greater strength was concluded in the present study. From the Refs. [17,37], same authors have done research using SF and MK as a partial substitute to the cement on mechanical properties. It was concluded that SF10 and MK20 was surpassing with other SF & MK SCC mixes is analogous with present durability results. SCC has obtained increase in compressive strength of 4.32%, 3.61% & 1.8% in respect of NVC under normal water curing at 28 days and immersed in H2SO4 solution for the duration of 28- and 56-days. SCC has obtained increase in compressive strength of 4.32%, 2.61% & 0.92% in respect of NVC under normal water curing at 28 days and immersed in Na2SO4 solution for the duration of 28- and 56-days. SCC with MK 30 obtained less percentage of water absorption (2.05%) in respect of NVC (3.3%) at 28-days. Considering the economic feasibility through economy index, SCC with 50% GGBFS, 20% MK and 5 to 10% of SF can be treated as optimum mixes in the respective category.
8
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
References [1] P. Dinakar, K.G. Babub, Manu K. Santhanam, Durability properties of high volume fly ash self compacting concretes, Cem. Concr. Compos. 30 (2008) 880– 886. [2] W. Watcharapong, T. Pailyn, N. Athipong, C. Arnon, Compressive strength and chloride resistance of self compacting concrete containing high level fly ash and silica fume, Mater. Des. 64 (2014) 261–269. [3] S. Dhiyaneshwaran, P. Ramanathan, I. Baskar, R. Venkatasubramani, Study on durability characteristics of self compacting concrete with fly ash, Jordan J. Civ. Eng. 7 (2013) 342–353. [4] Halit, The effect of silica fume and high volume class C fly ash on mechanical properties, chloride penetration and freeze–thaw resistance of self compacting concrete, Constr. Build. Mater. 22 (2008) 456–462. [5] E. Hassan, S. Adnan, Properties of self-consolidating concrete made with high volumes of supplementary cementitious materials, J. Mater. Civ. Eng. 25 (2013) 1579–1586. [6] G. Efstratios, I.P. Badogiannis, D.V. Sfikas, K.G. Voukia, S.G. Trezos, Tsivilis, Durability of metakaolin self-compacting concrete, Constr. Build. Mater. 82 (2015) 133–141. [7] V. Kannan, B. Ganesan, Chloride and chemical resistance of self compacting concrete containing rice husk ash and metakaolin, Constr. Build. Mater. 51 (2014) 225–234. [8] K.A. Eleftherios, P. Ioanna, P. Michail, Behavior of self compacting concrete containing ladle furnace slag and steel fiber reinforcement, Mater. Des. 59 (2014) 454–460. [9] W. Her-Yung, H. Wen-Liang, Durability of self-consolidating concrete using waste LCD glass, Constr. Build. Mater. 24 (2010) 1008–1013. [10] M.E. Rahman, A.S. Muntohar, V. Pakrash, B.H. Nagaratnam, D. Sujan, Self compacting concrete from uncontrolled burning of rice husk and blended fine aggregate, Mater. Des. 55 (2014) 410–415. [11] A.R. Ali, K. Ali, S. Morteza, A. Babak, Use of natural zeolite to produce selfconsolidating concrete with low Portland cement content and high durability, J. Mater. Civ. Eng. 25 (2013) 589–596. [12] K.S. Kosmas, S.A. Nikolaos, Durability of normal strength self-compacting concretes and their impact on service life of reinforced concrete structures, Constr. Build. Mater. 41 (2013) 491–497. [13] R. Vasusmitha, Rao P. Srinivasa, Strength and durability study of high strength self compacting concrete, Int. J. Mining, Metal Mech. Eng. 1 (2013) 18–26. [14] K. Antonios, F.P. Michael, I. Ioannis, Durability performance of self-compacting concrete, Constr. Build. Mater. 37 (2012) 320–325. [15] F. Dehwah, Corrosion resistance of self-compacting concrete incorporating quarry dust powder, silica fume and fly ash, Constr. Build. Mater. 37 (2012) 277–282. [16] G. Mehmet, G. Erhan, E.K. Mustafa, B. Veysel, M. Kasim, Fresh and hardened characteristics of self compacting concretes made with combined use of marble powder, limestone filler, and fly ash, Constr. Build. Mater. 37 (2012) 160–170. [17] S.S. Vivek, G. Dhinakaran, Effect of silica fume in flow properties and compressive strength of self compacting concrete, Int. J. Chem. Tech. Res. 8 (1) (2015) 01–05. [18] D. Anjali, S.S. Vivek, G. Dhinakaran, Compressive strength of metakaolin based self-compacting concrete, Int. J. Chem. Tech. Res. 8 (2) (2015) 622–625.
[19] S.S. Vivek, D. Anjali, G. Dhinakaran, Behaviour of concrete encased steel composite short column subjected to uniaxial static loading, Asian J. Civ. Eng. 17 (1) (2016) 67–74. [20] ASTM C 150/C150M-12, Standard specification for Portland cement, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2012. [21] ASTM C 127-12, Standard test method for density, relative density (specific gravity) and absorption of coarse aggregate, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2012. [22] ACI 211.1, Standard practice for selecting proportions for normal, heavyweight and mass concrete, American Concrete Institute, Farmington Hills, MI, USA, 1991. [23] EFNARC guidelines: The European guidelines for self-compacting concrete (Specification, Production, Use), May 2005. [24] Erhan Guneyisi, Mehmet Gesoglu, Kasim Mermerdas, Strength deterioration of plain and metakaolin concretes in aggressive sulfate environments, J. Mater. Civ. Eng. 22 (4) (2010) 403–407. [25] B. Pradhan, Corrosion behavior of steel reinforcement in concrete exposed to composite chloride-sulfate environment, Constr. Build. Mater. 22 (2014) 398– 410. [26] BS 1881-1983, Method for determination of water absorption, British standard testing concrete part 122, British Standards Institution, 2 Park Street London W1 A 2BS, 1983. [27] ASTM C 642-13, Standard test method for density, absorption, and voids in hardened concrete, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2013. [28] ASTM C 1585-13, Standard test method for measurement of rate of absorption of water by hydraulic-cement concretes, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2013. [29] G. Dhinakaran, K. Revanth Kumar, S. Vijayarakhavan, M. Avinash, Strength and durability characteristics of ternary blend and light weight HPC, Constr. Build. Mater. 134 (2017) 727–736. [30] A. Arash, M. Morteza, Effect of ground granulated blast furnace slag (GGBFS) on RCCP durability, Constr. Build. Mater. 141 (2017) 533–541. [31] T. Mohsen, B.O. Mongi, K. Abderrazek, Behavior of self-compacting concrete made with marble and tile wastes exposed to external sulfate attack, Constr. Build. Mater. 135 (2017) 335–342. [32] H. Siad, B.S. Kamali, H.A. Mesbah, G. Escadeillas, M. Mouli, H. Khelafi, Characterization of the degradation of self-compacting concretes in sodium sulfate environment: Influence of different mineral admixtures, Constr. Build. Mater. 47 (2013) 1188–1200. [33] P.R.D. Silva, J.D. Brito, Experimental study of the porosity and microstructure of self-compacting concrete (SCC) with binary and ternary mixes of fly ash and lime stone filler, Constr. Build. Mater. 86 (2015) 101–112. [34] A.A. Ramezanianpour, M.H. Khazali, P. Vosoughi, Effect of steam curing cycles on strength and durability of SCC: A case study in precast concrete, Constr. Build. Mater. 49 (2013) 807–813. [35] S. Gurpreet, S. Rafat, Effect of iron slag as partial replacement of fine aggregates on the durability characteristics of self-compacting concrete, Constr. Build. Mater. 128 (2016) 88–95. [36] K. Kanish, S.P. Singh, S. Bhupinder, Durability of self-compacting concrete made with recycled concrete aggregates and mineral admixtures, Constr. Build. Mater. 128 (2016) 67–76. [37] S. Vivek, G. Dhinakaran, Fresh and mechanical properties of metakaolin-based high-strength SCC, Jordan J. Civ. Eng. 11 (2) (2017) 325–333.
Contents lists available at ScienceDirect
Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat
Technical note
Durability characteristics of binary blend high strength SCC S.S. Vivek, G. Dhinakaran ⇑ School of Civil Engineering, SASTRA University, Thanjavur, India
a r t i c l e
i n f o
Article history: Received 3 January 2017 Received in revised form 27 March 2017 Accepted 7 April 2017
Keywords: Self compacting concrete Durability GGBFS Metakaolin Silica fume
a b s t r a c t SCC has emerged as an inevitable option in situations where there is scarcity of skilled labour at construction sites. In the present paper an attempt was made to produce SCC with three different supplementary cementitious materials as a partial substitute to cement in binary blend. Cement was replaced with ground granulated blast furnace slag (GGBFS) (25%, 50% & 75%), Metakaolin (MK) (10%, 20% & 30%) and Silica Fume (SF) (5%, 10% & 15%) respectively. Durability studies such as resistance against acid attack, sulphate attack, water absorption and sorptivity were done to evaluate the suitability of mineral admixtures. Experimental results of binary blend SCC were compared with concrete (NVC) to understand the effect of mineral admixtures. The results indicated low water absorption and lesser volume of permeable voids in MK based SCC compared to NVC. GGBFS based SCC (with 50% Substitution) exhibited better resistance against acid attack than NVC. No significant difference in weight loss was observed for concrete immersed in Na2So4 solution. SF with 10% substitution and MK with 20% substitution gave good results compared to control SCC. Hence it is concluded that SCC could be produced with supplementary cementitious materials without compromising on durability. Ó 2017 Elsevier Ltd. All rights reserved.
1. Introduction The placement of concrete in different locations needs detailed studies on cause and effect relating to deterioration of concrete. In locations such as marine environment, underground, etc., there is severe durability problem by carbonation, sulphate, acid and chloride attack. To overcome the above problem, SCC is an obvious answer, since SCC has better flow, passing and filling ability compared to normal vibrated concrete. The SCC was developed by Okamura in Japan to overcome unskilled labour problem in the construction industry. Later SCC has been used in primary, repair and rehabilitation works in Switzerland and other countries. Self Compacting Concrete is a densely packed concrete having closer Interfacial Transition Zone (ITZ) compared to Normal Vibrated Concrete (NVC). Thus SCC is less porous as it forms a better C-SH gel by interlocking the aggregates and binder matrix. SCC has been made in three ways, namely, adding more powder content in the form of mineral admixtures, adding chemical admixtures in the form of Super Plasticizers and Viscosity Modifying Agents (VMA) or a combination of both. Hence in the present study, SCC with a combination of mineral and chemical admixtures has been formulated to study its durability properties. To maintain economy, cement was replaced by three different mineral admixtures ⇑ Corresponding author. E-mail address: [email protected] (G. Dhinakaran). http://dx.doi.org/10.1016/j.conbuildmat.2017.04.063 0950-0618/Ó 2017 Elsevier Ltd. All rights reserved.
as mentioned above. Since cement employed was Ordinary Portland Cement (OPC), pozzolanic activity developed due to mineral admixtures could be easily understood. Dinakar et al. [1] made a detailed experimental study on SCC with different mineral admixtures pertaining to mix design, strength characteristics and durability characteristics. In this research paper, replacement levels of 0%, 10%, 30%, 50%, 70% and 85% with fly ash for strength comparison with normal vibrated concrete. They found that concrete specimens after immersion in 3% H2SO4 solution experienced lesser weight loss with increasing fly ash content and consequently lower chloride permeability than normal concrete. Hence SCC exhibited better durability compared to NVC in terms of high permeable voids, water absorption and resistance to segregation. Watcharapong et al. [2] made an experimental investigation on strength and resistance to chloride for ternary blended SCC containing high volume fly ash (ranging from 40 to 70%) and silica fume (ranging from 0 to 10%). With the above ternary combination of two mineral admixtures, a target strength of more than 60 MPa was obtained. In respect of durability, volume of voids and water absorption was studied. It was found that the durability characteristics improved significantly due to fly ash in SCC. Dhiyaneshwaran et al. [3] made durability study using fly ash from 10% to 50%. It was found that concrete specimens after immersion in 10% Na2SO4 solution showed no weight loss for any period of time. The weight loss of concrete specimens after
2
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
immersion in 10% HCl solution increased with respect to time. 30% dosage of fly ash reduced water absorption. Halit [4] carried out research using Class C fly ash in high volume to obtain SCC durability characteristics. They found that incorporation of 60% FA and 10% SF in SCC had higher resistance to chloride and freez-thaw. The compressive strength of binary and ternary mix was better than control mix after freez-thaw. Hassan and Adnan [5] studied the influence of quaternary blend incorporating supplementary cementitious materials. Cement was replaced to an extent of 70%. It was inferred from the results that concrete with 10% SF gave better compressive strength but reduced workability. Use of fly ash improved the workability and later age strength. Efstratios et al. [6] made research work on SCC durability using MK as cement replacement at higher levels, which enhanced better resistance to chloride penetration. Both penetration and migration coefficients correlated well with strength for MK based SCC. Kannan and Ganesan [7] performed experiments to study durability of RHA and MK based SCC. MK was used up to 30% and RHA was used up to 40%. Durability properties improved with 30% MK compared to the control mix. In a ternary mix, 15% RHA and 15% MK were found to be optimum. Eleftherios et al. [8] investigated the behaviour of SCC utilizing ladle furnace slag with 600 to 1200 N/m3 and 0.7% fibre reinforcement. The authors concluded that ladle furnace slag inclusion showed better results in respect of durability. It also enhanced resistance to freez-thaw and chloride penetration. Her Yung and Wen Liang [9] used LCD glass as aggregate up to 30% in SCC and found that the rheological properties improved with higher magnitude of LCD glass as substitute. Resistance against corrosion due to sulphate was better in LCD glass based SCC. An optimum value of 30% was proposed from their work. Rahman et al. [10] made a study on SCC using RHA as filler with replacement levels of 0% to 40% by total cement mass along with blended fine aggregates. The concrete properties in fresh and hardened states as well as water absorption were studied. For a SCC mix with RHA at 8% to 12%, good correlation was observed between compression and tension. RHA, as a CRM in concrete was directly proportional to water absorption. It was worthy to note that good resistance to segregation of 0.04 –0.2% was obtained. Ali et al. [11] made an investigation on SCC replacing cement with natural zeolite NZ (0%, 10%, 15%, 20%, 25%, 30%). Fresh concrete properties such as flow ability, passing ability and stability criteria were satisfied as per EFNARC with NZ dosage ranging from 10% to 25%. It was concluded from RCPT and electrical resistivity tests that durability of SCC got enhanced by the addition of natural zeolite. Resistance to segregation also improved by the inclusion of natural zeolite up to 30%. Kosmas and Nikolaos [12] experimentally investigated the durability properties of normal strength SCC and their effect on RC structures. The results were compared with conventionally vibrated concrete. From the test results, penetration depth values were found to be low even at higher w/c ratios. Hence SCC exhibited better longevity compared to CVC. Vasusmitha and Srinivasa Rao [13] investigated the effect of different mineral admixtures on tension and permeation of high strength self compacting concrete. The results indicated that HSSCC exhibited lower chloride permeability on concrete, dense micro structure, higher bond and tensile strength, lower permeability to oxygen and lower plastic settlement. Antonios et al. [14] studied the durability properties of SCC and conventional concrete through sorptivity, porosity and chloride ion permeability tests. Silica fume inclusion in SCC imparts lower porosity, capillary absorption and chloride ion permeability in a shorter duration of 28 days. Dehwah [15] studied the effect of mineral admixtures on resistance to corrosion, permeation and chloride ion diffusion. The chlorination depth was moderate for QDP or FA but it was lower for SF
+ QDP. SCC with 8% quarry dust powder (w/p 0.38) or with 8% quarry dust powder +5% SF was found to perform well. Mehmet et al. [16] investigated the rheological and transport properties of SCC with mineral admixtures. They used marble powder, limestone filler and fly ash as mineral admixtures. It was found that higher replacement levels affect the rheological properties and the sorptivity of admixed SCC was better than control mix. Marble powder and limestone filler enhanced the properties of hardened SCC. The role of silica fume and Metakaolin on fresh concrete properties as well as compressive strength of SCC was studied by Vivek and Dhinakaran [17–19,37] and they found that mineral admixtures play a vital role in modifying the properties of SCC. Among the durability test, the most common tests are water absorption, sorptivity, permeability and exposure to aggressive environment was conducted by Dhinakaran et al. [29] on HPC using optimum GGBS 20%, Quartz powder 10% with addition of AEA and LWA respectively. Arash and Morteza [30] investigated on Roller Compacted Concrete using GGBFS 40% have reduced porosity, water absorption and permeability properties. Similarly many durability studies were performed in SCC also. Mohsen et al. [31] performed research on durability of SCC using marble and tile wastes subjected to sulphate attack. The sulphate resistance offered by those factory wastes in SCC was higher than ordinary vibrated concrete was concluded. Siad et al. [32] studied that addition of natural pozzolan have more benefit than fly ash on SCC against sodium sulphate attack. Silva and Brito [33] investigated that SCC could be prepared using fly ash and lime stone filler as binary and ternary mixes to obtain the porosity and microstructure. The results infer that SCC of ternary blend could be mostly favourable. Ramezanionpour et al. [34] reported that SCC could also be employed in developing precast concrete elements under 36 different types of steam curing. For which the compressive strength and permeability was studied and reveals that if the temperature exceeds 70 °C results in negative effect on durability. Gurpreet [35] made research on SCC using the iron slag as a partial replacement of fine aggregate in order to study the durability characteristics of SCC. Kanish [36] investigated on durability performance of SCC using RCA’s and Mineral admixtures. From the available literature, it was found that many research works were available on resistance of SCC to chloride ion penetration and SF and FA based SCC. Hence in the present research three types of mineral admixtures namely MK, SF and GGBFS was used to study the durability properties of binary blended SCC by conducting water absorption, acid resistance, alkaline resistance and sorptivity tests. The obtained results of SCC were compared with those of Normal Vibrated Concrete (NVC).
2. Materials and methods 2.1. Material properties For the experimental programme, the following materials used and tested according to standards as discussed below. ASTM Type I [20] cement was used in the present work. Fine aggregate used was natural river sand and coarse aggregate was crushed granite. The specific gravity of FA used was 2.60 and that CA used was 2.65. Coarse aggregate specific gravity was found out using wire basket method in accordance with ASTM C 127 [21]. The maximum size of coarse aggregate used in the present work was limited to 12.5 mm. Table 1 gives chemical compositions of cement and other binary mineral admixtures employed for SCC. The super plasticizer (2.3% weight of cement) used was sulphonated naphthalene formaldehyde based was employed. Viscosity modifying admixture (VMA) (0.15% of weight of cement) was used to reduce segregation and bleeding. The combination type of binary blended SCC was pre-
3
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8 Table 1 Chemical composition of cement and mineral admixtures. Component (%)
Cement
GGBFS
MK
SF
SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O SO3 LOI
21.78 6.56 4.13 60.12 2.08 0.36 0.42 2.16 2.39
33.1 16.6 0.6 34.8 8.0 0.2 0.5 0.4 0.3
52.56 44.10 0.45 0.28 0.2 0.25 0.2 0 0.85
93.55 0.56 0.17 1.13 0.75 0.14 1.05 1.01 1.16
pared by combining cement, aggregates, mineral and chemical admixtures with water to powder ratio of 0.4 (arrived from laboratory trials). The proportions of fine aggregate and coarse aggregate was adjusted from the conventional concrete mix in order to obtain the flow ability, passing and filling ability since these are mandatory for SCC mix. Table 2 give the details of materials utilized in the present research work. SF is obtained from silicon industry. As a pozzolanic mineral, when it is combined with super plasticizers that will enhance the mechanical properties in the range of 100–150 MPa. MK is refined kaolin clay which was calcined under controlled conditions, having high pozzolanic activity. MK develops increase in compressive strength, better surface finishes and reduce efflorescence. GGBS is a by-product obtained from the blast furnaces in the manufacturing process of iron or steel, enhances tensile strength, elastic modulus, superior surface finishes and caters the durability problem. The mineral admixtures when employed in mix composition the rheological properties of SCC will be improved. 2.2. Mix design The concrete mix proportioning was performed for concrete with a characteristic compressive strength of 60 MPa in accordance with ACI 211.1-91 [22]. For laboratory trials, initial mix proportion of 1:1.6:1.6 (Binder: Sand: CA) was exhibited with the water to binder ration maintained at 0.40 and by obtaining the flow properties, the final mix proportion was illustrated in Table 2. To develop a SCC mix, the key parameters include W/P ratio, dosage of super plasticizer and stabilizer, proportion of fine aggregate to coarse aggregate. Details of rheological properties of SCC developed were already published by the authors of the present research work and were available in literature [17]. 2.3. Methods The experimental programme was aimed at studying the durability characteristics of SCC using three different percentages of
GGBFS (25, 50, 75), SF (5, 10, 15) and MK (10, 20, 30) as a substitute for cement. All the tests for fresh concrete properties were conducted as per EFNARC guidelines for SCC and the details are available in [23]. Since sulphate attack is a prime factor which creates problems in concrete, leading to severe damages such as cracking, expansion and disintegration of concrete 1585 [24], the behaviour of SCC specimens subjected to acid attack was studied in the present work. To assess the behaviour of SCC in aggressive environment and to study the effect of sulphate attack on concrete, the specimens were subjected to curing in diluted H2SO4 acid, which the structures encounter frequently in industries. 1% H2SO4 acid was used in this work to observe the deterioration of concrete when cured in it. Severe durability problem occurs in marine environment due to chloride attack [25]. To simulate the effect of marine environment and to study their behaviour in an aggressive marine environment, 5% sodium chloride was used in this study for curing the concrete specimens. BS 1881 [26] guidelines were followed in casting the specimens meant for compressive strength and were tested in the designated period. Voids or pores in the prepared concrete were determined in accordance with ASTM C642 [27]. A short-term durability property called sorptivity of concrete was assessed in accordance with ASTM C1585 [28]. The details of experimental set-up for the above tests are given in Figs. 1 to 3. 3. Results and discussion 3.1. Effect of GGBFS on durability of SCC SCC made with GGBFS absorbs fewer amounts of water than control SCC and NVC. Among three different percentages of GGBFS used, SCC with 50% of GGBFS gave better results than the other two mixes. SCC with more than 50% of GGBFS as substitute to cement lead to more permeable voids due to its higher volume. Similar trend was followed in volume of voids also, since both are directly proportional. Volume of voids for SCC with 50% GGBFS was found to be less than NVC and control SCC. In sorptivity, water absorption and permeable pore test, GGBFS with 50% of cement replacement showed significant improvement compared to other two mixes. It was due to the fineness of the slag material as 50% in cement content caused better conglomeration of SCC GGBFS mix that improved resistance to capillary action. Hence the pores of the concrete micro structure was completely filled with the powder content namely slag causing water tight for capillary rise. For SCC specimens subjected to 28- and 56-days curing in H2SO4 solution, the deterioration of concrete was ascertained based on the percentage weight loss. Here GGBFS SCC with 75%
Table 2 Constituents of SCC mixes. Materials (kg/m3)
Cement GGBFS MK SF Water W/P FA CA SP VMA No. of Specimens cast
NVC
600 – – – 196 0.40 412 1113 – – 3 specimens
SCC
600 – – –
GGBFS
Metakaolin
Silica fume
25%
50%
75%
10%
20%
30%
5%
10%
15%
– 150 – –
– 300 – –
– 450 – –
– – 60 –
– – 120 –
– – 180 –
– – – 30
– – – 60
– – – 90
834 686 13.8 0.90 each for 28 days and 56 days in each mix (Total: 66 Nos.)
4
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
Fig. 1. Water absorption and voids tests in progress.
Fig. 2. Specimens (a) before (b) during (c) after exposure to H2SO4 solution.
Fig. 3. Specimens (a) before (b) during (c) after exposure to Na2SO4 solution.
cement replacement showed lesser weight loss compared to the other two mixes. In sulphate attack, there was no weight loss observed with the other mixes. In SCC, GGBFS could be used in the range of 50% to 75% where matters a lot (see Figs. 4 and 5). 3.2. Effect of MK on durability of SCC Metakaolin MK was used as replacement for cement in the range of 0% to 30% with an increment of 10% respectively. From the experimental results, MK could be used from 20% to 30%, since 20% MK showed better performance in respect of sorptivity and apparent density. SCC with 30% MK exhibited better resistance against water absorption, porosity and acid attack at 28 and
56 days. There was no weight loss in the context of sulphate attack, both at 28- and 56- days. The calcined clay content improved the durability of SCC with increase in%MK since it is highly pozzolanic in nature. The pozzolan caused slow strength gain at early ages but at later ages, durability and strength got improved appreciably. Since OPC was used, addition of MK influenced the pozzolanic nature in SCC. Hence higher replacement levels with MK could be used where the long-term durability is a concern. 3.3. Effect of SF on durability of SCC SCC with 10% SF performed well in respect of sorptivity. SCC with 5% SF was better in terms of water absorption and permeable
5
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
6.67
6.71
6.23
2.71
2.67
2.45
2.05
2.34
2.56
3
3.04
2.61
2.69
4
2.63
5
3.29
6
5.12
5.53
7
6.31
6.86
6.24
6.71
6.43
8
Value in Percentage
Volume of Voids (%)
8.08
Water Absorption (%) 9
2 1 0
Fig. 4. Effect of GGBFS, SF and MK on Water absorption and permeable pores.
5
15.47
17.81
18.1
9.7
9.44
9.91
13.42 8.32
9.81
15.23
17.16 9.41
6.67
3.73
6.45
10
8.7
15
9.58
20 10.19
Value in Percentage
25
Weight loss in H2SO4 [56 days]
18.47
22.6
27
24.45
Weight loss in H2SO4 [28 days] 30
0
Fig. 5. Effect of GGBFS, SF and MK on weight loss in acids.
pore space. SCC with 15% SF was better in respect of apparent density and resistance to acid attack at 28- and 56- days respectively. There was no weight loss after 28- and 56-days of curing in sulphate solution. Thus SF used should be restricted to 15% for a binary blended SCC since it has silica and ferrous (iron) content which would cause corrosion of embedded reinforcing bars under severe exposure conditions.
3.4. Comparison of NVC and SCC (without cement replacement) On comparing SCC with NVC, it was found that there was wide variation in the values of sorptivity test, water absorption test, permeable pore space, apparent density and acid resistance (immersion in 5% of H2SO4 solution) at 28- and 56-days. There was negligible weight loss for both NVC and SCC after immersion in 5% Na2SO4 solution for 28- and 56-days. In the above durability tests, NVC performed better than SCC (without cement replacement). This was mainly due to the mixture composition i.e. fines were higher than coarse aggregates and also significant effect of water powder ratio in SCC mix (refer Table 2). The influence of super plasticizer and VMA dosages also influence the durability of SCC. In overall study, in sorptivity test GGBFS 50%, in water absorption and permeable pore test MK30%, in apparent density MK20% obtained better results compared to other SCC mixes and NVC. Immersion of cube specimens in 5% of H2SO4 solution of various
mixes at 28 and 56 days, GGBFS 75% performed better compared to other SCC mixes and NVC. Similar results were obtained by Dinakar et al. [1] in respect of durability with fly ash inclusion in SCC. After immersion in 3% H2SO4 solution, the deterioration of fly ash based SCC decreased with increasing fly ash content. In the present work, after immersion in 5% H2SO4 solution, SCC with GGBFS 75% showed good correlation with similar studies on durability. The results obtained from Kannan and Ganesan [7] blended SCC with MK 30% performed better in respect of permeability and was in line with similar studies. After immersion in 5% Na2SO4 solution, there was no weight loss for any length of time and this was similar to the results of Dhiyaneshwaran et al. [3] but the percentage of Na2SO4 was different. 3.5. Compressive strength of concrete 3.5.1. After immersion in acid (H2SO4) solution For concrete specimens, after immersion in H2SO4 solution for 28- and 56- days the loss in compressive strength was determined as per ASTM standard. Fig. 6 shows the compressive strength obtained under different curing conditions for all the 11 mixes. The compressive strength (difference) closer to 5 MPa was obtained for SCC with SF 5% and 10% respectively at the age of 28 and 56 days. The remaining mixes exhibited reduced compressive strength (difference) in the range of minimum 2 MPa to maximum 6 MPa indicating that 50% of strength was lost in acid
6
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
Compressive Strength in Water Curing [28 days]
Compressive Strength in H2SO4 [28 days]
Compressiv Strength in MPa
Compressive Strength in H2SO4 [56 days] 180 160 140
50.5
51.4 42.5
120 52.6
54.5
44.5
51.8
48.7
62.5
65.2
62.58
20
59.08
56.00
46.2
41.6
44.8 32.4
38.8
51.4
50.8
36.7
46.5
44.6
55.38
51.56
60.06
58.1
55.3
47.5
60 40
47.2
43.9 43.4
100 80
47.8
0
Fig. 6. Compressive strength of admixed SCC cured under water and H2SO4 solution.
solution at the age of 56- days. When acid reacts with concrete, the interlocking between the cement matrix and aggregate as C-S-H gel was broken down. The specimens kept under acid curing exhibited white patches on their surfaces. Honeycombing was also noticed on their surfaces due to acid attack. 3.5.2. After immersion in base (Na2SO4) solution After normal water curing, the concrete specimens were cured in Na2SO4 solution for a period of 28- and 56-days. Fig. 7 shows compressive strength obtained under different curing conditions for all the 11 mixes. SCC with MK 30% exhibited a compressive strength (difference) of 10.76 MPa and 12.66 MPa after 28- and 56-days of sulphate curing in respect of 28 days of normal water curing. Whereas for other mixes, the compressive strength (difference) between normal and sulphate curing obtained was in the range of 24 MPa (37%) to 26 MPa (40%) at 28- and 56-days respectively. In some mixes namely the strength loss was nil even at the two different ages of curing in Na2SO4 solution. The surface texture of the specimen was not affected by curing in base solution. There was minor strength loss in NVC and other SCC specimens to the tune of 10% when cured in base solution. 3.6. Evaluation of sorptivity characteristics The resistance against capillary suction due to the effect of mineral admixtures in SCC was studied by conducting sorptivity test as per ASTM C1585-13. It was found that the sorption coefficient for
control SCC was 23% more than normal vibrated concrete. It could be due to higher degree of flowability of SCC. However, in the case of SCC with GGBFS (25% and 50%), the sorption coefficient was found to be less compared to normal SCC; even it was lesser than the normally vibrated concrete. For SCC with 75% GGBFS, the sorption coefficient was little bit higher than the NVC and less than the control SCC. When MK was added to the tune of 10%, the sorption coefficient was on par with control SCC and with higher replacement levels, it performed better. SCC with SF10% showed better results and the other two mixes exhibited higher sorption coefficients. The reason could be inadequate replacement level with SF. Among the three different admixtures used in the present work, SCC with GGBFS and MK performed better when compared to SCC with SF (Fig. 8). 4. Cost analysis In the present research paper cost analysis was done through an economy index. Economy index is the ratio between strength and cost. In many of the works cost of concrete production was taken as a major deciding factor, whereas here the economic feasibility was obtained with the ratio of strength and cost. Compressive strength at the age of 28 days and cost of materials as per present scenario was taken to arrive at an economy index. Optimum mix was obtained based on these criteria. The economy index arrived for various mixes are tabulated in the Table 3. SCC gave better economy index than NVC due to its higher compressive strength. For
Compressive Strength in Water Curing [28 days]
Compressive Strength in Na2SO4 [28 days]
Compressive Strength in Na2SO4 [56 days]
Compressiv Strength in MPa
200 180 160 140
54.5
55
56.7
54.6 52.8
120 100
43.8 57.5
59
58.2
80
58.5
51.2
20
62.5
65.2
62.58
59.08
56.00
51.3
46.2
45.8
52.6
54
58.5
60.06
58.1
51.8
38.9
45.8
60 40
45.7
55.38
40.8
51.56
0
Fig. 7. Compressive strength of admixed SCC cured under water and Na2SO4 solution.
51
55.3
7
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
2.3
2.7
2.8 1.9
2
2.4
2.00
1.8
1.9
2.40
2.6
2.6
2.80
2.1
Sorption Coefficient (in 10-2 mm/S1/2 )
3.20
1.60 1.20 0.80 0.40 0.00
Fig. 8. Effect of GGBFS, MK and SF on resistance against sorption.
Table 3 Calculation of economy index (per m3 of Concrete). Mix Description
NVC SCC GGBFS 25 GGBFS 50 GGBFS 75 MK 10 MK 20 MK 30 SF 5 SF 10 SF 15
Mass in kg Cement
Slag
MK
SF
FA
CA
600 600 450 300 150 540 480 420 570 540 510
0 0 150 300 450 0 0 0 0 0 0
0 0 0 0 0 60 120 180 0 0 0
0 0 0 0 0 0 0 0 30 60 90
412 412 412 412 412 412 412 412 412 412 412
1113 1113 1113 1113 1113 1113 1113 1113 1113 1113 1113
SCC with GGBFS, this index ranged from 0.87 to 2.27. Among three mix combinations, SCC with 50% GGBFS can be considered as an optimum due to its strength magnitude at par with characteristic compressive strength. In the case of MK based SCC, increase of MK from 10 to 20% increased the economic index and further increase of MK to 30% showed a reduction in this index. It can be due to reduction in strength. Hence SCC with 20% MK can be an optimal mix in that category by compromising strength to 8%, which is permissible in the field. In the case of SCC with SF, concrete with SF5 gave better results in terms of strength and SF10 also acceptable in terms of economy index. 5. Conclusions Following are the conclusions drawn from the experiments performed on binary blend self compacting concrete using GGBFS, SF and MK as mineral admixtures. Based on tests conducted in the laboratory for fresh concrete properties, water to powder ratio was ascertained as 0.4 and optimum dosages of super plasticizer & stabilizer as 2.3% and 0.15% by weight of cement. From durability studies, it was found that SCC with CRM’s performed better than NVC and SCC without CRM’s. In the formulation of binary blended SCC, in respect of durability, the following replacement levels could be suggested: U Cement replacement with GGBFS at 50% to 75% would result in a better durable SCC mix. U Cement replacement level with SF shall be restricted to 15% for ensuring durability at critical locations.
Total Cost/m3 (US $)
Comp. Strength (MPa)
Economy Index (Strength/Cost)
85.58 85.58 71.73 57.88 24.63 87.42 89.27 91.11 88.35 92.04 95.27
62.50 65.20 62.58 59.08 56.00 46.20 55.38 51.36 60.06 58.10 55.30
0.73 0.76 0.87 1.02 2.27 0.53 0.62 0.56 0.68 0.63 0.58
U MK could be used in SCC at 20% to 30% as CRM. The percentage weight loss after immersion in 5% H2SO4 solution at 28 and 56 days was found to be lower for SCC with 75% GGBFS, 15%SF and 30%MK inferring that higher replacement levels were beneficial. The percentage weight loss was zero for all 11 mixes after immersion in 5% Na2SO4 solution at 28 and 56 days curing. SCC with 50% GGBFS, 20% MK and 10% SF exposed to sulphuric acid exhibited greater strength among the nine different mixes used. Similar trend was observed for SCC mixes exposed to sodium sulphate solution also. SCC with SF 10% exhibited greater strength was concluded in the present study. From the Refs. [17,37], same authors have done research using SF and MK as a partial substitute to the cement on mechanical properties. It was concluded that SF10 and MK20 was surpassing with other SF & MK SCC mixes is analogous with present durability results. SCC has obtained increase in compressive strength of 4.32%, 3.61% & 1.8% in respect of NVC under normal water curing at 28 days and immersed in H2SO4 solution for the duration of 28- and 56-days. SCC has obtained increase in compressive strength of 4.32%, 2.61% & 0.92% in respect of NVC under normal water curing at 28 days and immersed in Na2SO4 solution for the duration of 28- and 56-days. SCC with MK 30 obtained less percentage of water absorption (2.05%) in respect of NVC (3.3%) at 28-days. Considering the economic feasibility through economy index, SCC with 50% GGBFS, 20% MK and 5 to 10% of SF can be treated as optimum mixes in the respective category.
8
S.S. Vivek, G. Dhinakaran / Construction and Building Materials 146 (2017) 1–8
References [1] P. Dinakar, K.G. Babub, Manu K. Santhanam, Durability properties of high volume fly ash self compacting concretes, Cem. Concr. Compos. 30 (2008) 880– 886. [2] W. Watcharapong, T. Pailyn, N. Athipong, C. Arnon, Compressive strength and chloride resistance of self compacting concrete containing high level fly ash and silica fume, Mater. Des. 64 (2014) 261–269. [3] S. Dhiyaneshwaran, P. Ramanathan, I. Baskar, R. Venkatasubramani, Study on durability characteristics of self compacting concrete with fly ash, Jordan J. Civ. Eng. 7 (2013) 342–353. [4] Halit, The effect of silica fume and high volume class C fly ash on mechanical properties, chloride penetration and freeze–thaw resistance of self compacting concrete, Constr. Build. Mater. 22 (2008) 456–462. [5] E. Hassan, S. Adnan, Properties of self-consolidating concrete made with high volumes of supplementary cementitious materials, J. Mater. Civ. Eng. 25 (2013) 1579–1586. [6] G. Efstratios, I.P. Badogiannis, D.V. Sfikas, K.G. Voukia, S.G. Trezos, Tsivilis, Durability of metakaolin self-compacting concrete, Constr. Build. Mater. 82 (2015) 133–141. [7] V. Kannan, B. Ganesan, Chloride and chemical resistance of self compacting concrete containing rice husk ash and metakaolin, Constr. Build. Mater. 51 (2014) 225–234. [8] K.A. Eleftherios, P. Ioanna, P. Michail, Behavior of self compacting concrete containing ladle furnace slag and steel fiber reinforcement, Mater. Des. 59 (2014) 454–460. [9] W. Her-Yung, H. Wen-Liang, Durability of self-consolidating concrete using waste LCD glass, Constr. Build. Mater. 24 (2010) 1008–1013. [10] M.E. Rahman, A.S. Muntohar, V. Pakrash, B.H. Nagaratnam, D. Sujan, Self compacting concrete from uncontrolled burning of rice husk and blended fine aggregate, Mater. Des. 55 (2014) 410–415. [11] A.R. Ali, K. Ali, S. Morteza, A. Babak, Use of natural zeolite to produce selfconsolidating concrete with low Portland cement content and high durability, J. Mater. Civ. Eng. 25 (2013) 589–596. [12] K.S. Kosmas, S.A. Nikolaos, Durability of normal strength self-compacting concretes and their impact on service life of reinforced concrete structures, Constr. Build. Mater. 41 (2013) 491–497. [13] R. Vasusmitha, Rao P. Srinivasa, Strength and durability study of high strength self compacting concrete, Int. J. Mining, Metal Mech. Eng. 1 (2013) 18–26. [14] K. Antonios, F.P. Michael, I. Ioannis, Durability performance of self-compacting concrete, Constr. Build. Mater. 37 (2012) 320–325. [15] F. Dehwah, Corrosion resistance of self-compacting concrete incorporating quarry dust powder, silica fume and fly ash, Constr. Build. Mater. 37 (2012) 277–282. [16] G. Mehmet, G. Erhan, E.K. Mustafa, B. Veysel, M. Kasim, Fresh and hardened characteristics of self compacting concretes made with combined use of marble powder, limestone filler, and fly ash, Constr. Build. Mater. 37 (2012) 160–170. [17] S.S. Vivek, G. Dhinakaran, Effect of silica fume in flow properties and compressive strength of self compacting concrete, Int. J. Chem. Tech. Res. 8 (1) (2015) 01–05. [18] D. Anjali, S.S. Vivek, G. Dhinakaran, Compressive strength of metakaolin based self-compacting concrete, Int. J. Chem. Tech. Res. 8 (2) (2015) 622–625.
[19] S.S. Vivek, D. Anjali, G. Dhinakaran, Behaviour of concrete encased steel composite short column subjected to uniaxial static loading, Asian J. Civ. Eng. 17 (1) (2016) 67–74. [20] ASTM C 150/C150M-12, Standard specification for Portland cement, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2012. [21] ASTM C 127-12, Standard test method for density, relative density (specific gravity) and absorption of coarse aggregate, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2012. [22] ACI 211.1, Standard practice for selecting proportions for normal, heavyweight and mass concrete, American Concrete Institute, Farmington Hills, MI, USA, 1991. [23] EFNARC guidelines: The European guidelines for self-compacting concrete (Specification, Production, Use), May 2005. [24] Erhan Guneyisi, Mehmet Gesoglu, Kasim Mermerdas, Strength deterioration of plain and metakaolin concretes in aggressive sulfate environments, J. Mater. Civ. Eng. 22 (4) (2010) 403–407. [25] B. Pradhan, Corrosion behavior of steel reinforcement in concrete exposed to composite chloride-sulfate environment, Constr. Build. Mater. 22 (2014) 398– 410. [26] BS 1881-1983, Method for determination of water absorption, British standard testing concrete part 122, British Standards Institution, 2 Park Street London W1 A 2BS, 1983. [27] ASTM C 642-13, Standard test method for density, absorption, and voids in hardened concrete, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2013. [28] ASTM C 1585-13, Standard test method for measurement of rate of absorption of water by hydraulic-cement concretes, American Society for Testing and Materials, ASTM International, West Conshohocken, PA, USA, 2013. [29] G. Dhinakaran, K. Revanth Kumar, S. Vijayarakhavan, M. Avinash, Strength and durability characteristics of ternary blend and light weight HPC, Constr. Build. Mater. 134 (2017) 727–736. [30] A. Arash, M. Morteza, Effect of ground granulated blast furnace slag (GGBFS) on RCCP durability, Constr. Build. Mater. 141 (2017) 533–541. [31] T. Mohsen, B.O. Mongi, K. Abderrazek, Behavior of self-compacting concrete made with marble and tile wastes exposed to external sulfate attack, Constr. Build. Mater. 135 (2017) 335–342. [32] H. Siad, B.S. Kamali, H.A. Mesbah, G. Escadeillas, M. Mouli, H. Khelafi, Characterization of the degradation of self-compacting concretes in sodium sulfate environment: Influence of different mineral admixtures, Constr. Build. Mater. 47 (2013) 1188–1200. [33] P.R.D. Silva, J.D. Brito, Experimental study of the porosity and microstructure of self-compacting concrete (SCC) with binary and ternary mixes of fly ash and lime stone filler, Constr. Build. Mater. 86 (2015) 101–112. [34] A.A. Ramezanianpour, M.H. Khazali, P. Vosoughi, Effect of steam curing cycles on strength and durability of SCC: A case study in precast concrete, Constr. Build. Mater. 49 (2013) 807–813. [35] S. Gurpreet, S. Rafat, Effect of iron slag as partial replacement of fine aggregates on the durability characteristics of self-compacting concrete, Constr. Build. Mater. 128 (2016) 88–95. [36] K. Kanish, S.P. Singh, S. Bhupinder, Durability of self-compacting concrete made with recycled concrete aggregates and mineral admixtures, Constr. Build. Mater. 128 (2016) 67–76. [37] S. Vivek, G. Dhinakaran, Fresh and mechanical properties of metakaolin-based high-strength SCC, Jordan J. Civ. Eng. 11 (2) (2017) 325–333.