International Journal of Civil Engineering and Technology (IJCIET) Volume 10, Issue 04, April 2019, pp. 1983–1991, Article ID: IJCIET_10_04_207 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJCIET&VType=10&IType=4 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication Scopus Indexed BEHAVIOUR OF CONCRETE INCORPORATING TIREDERIVED CRUMB RUBBER AGGREGATE Firas F. Jirjees Road Construction Department, Erbil Technology Institute, Erbil Polytechnic University, Erbil, Iraq Shelan M. Maruf Road Construction Department, Erbil Technology Institute, Erbil Polytechnic University, Erbil, Iraq Ahmed R. Abdul Rahman Surveying Department, Erbil Technology Institute, Erbil Polytechnic University, Erbil, Iraq Khaleel H. Younis Road Construction Department, Erbil Technology Institute, Erbil Polytechnic University, Erbil, Iraq Environmental Engineering Department, Knowledge University, Erbil, Iraq ABSTRACT An experimental study on the performance of concrete containing waste-tires based fine aggregate is presented in this paper. This study examines the effect of replacing the natural fine aggregate (NFA) with recycled fine aggregate (RFA) on the workability and mechanical properties of concrete. The mechanical properties include: compressive strengthand tensile strength. Various RFA replacement ratios were used including (10%, 20%and 30%). Four mixes were examined: three with different RFA replacement ratios and one mix with NFA for comparison purpose. The results show that RFA reduces both the workability and the mechanical properties of concrete. Key words: Sustainable concrete, mechanical properties, waste tires, crumb rubber, recycled fine aggregate, tensile strength Cite this Article: Firas F. Jirjees, Shelan M. Maruf, Ahmed R. Abdul Rahman, Khaleel H. Younis, Behaviour of Concrete Incorporating Tirederived Crumb Rubber Aggregate, International Journal of Civil Engineering and Technology 10(4), 2019, pp. 1983–1991. http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=10&IType=4 http://www.iaeme.com/IJCIET/index.asp 1983 editor@iaeme.com Firas F. Jirjees, Shelan M. Maruf, Ahmed R. Abdul Rahman, Khaleel H. Younis 1. INTRODUCTION Nowadays, the issues related to the accumulation of vast amounts of waste are globally documented; in particular the waste originated from used tires[1, 2].Recent studies have reported that thousands of millions of tires are produced every year worldwide[1-3].All parts of the world including developed and developing countries are facing the problem of such enormous number of tires accumulated every year (See Figure 1). The disposal of such vast number of waste tires has a large impact on the environment. Also, waste tires can cause serious issues to the human health and increase fire hazards in the case of burning or illegal dumping [1, 3]. A suitable sustainable solution to such serious environmental issues is the utilization of such waste of tires in the production of concrete [2]. Figure 1 Accumulation of waste tires in Erbil city-Iraq (photo taken in 2018) The utilization of the rubber extracted from waste tires as fine aggregate in the production of concrete could be a decent solution for the issues associated with the disposal of waste tires [2].This will also enhance the sustainability of concrete and lead to develop an eco-friendly concrete through eliminating the consumptions of limited areas of landfilling, reduce the hazards and health problems associated with tires disposal; and save the natural recourses of sand[1, 2]. The performance of concrete incorporating crumb rubber as fine aggregate has been studied by severalresearchers globally [1, 4-10] but very limited work has been done in Iraq. These studies have shown that the use of recycled aggregatesuch as crumb rubber extracted from waste tires were resulted ina concrete with lower quality than concrete made with natural fine aggregate[1, 7]. The use of waste-tires based fine aggregate diminishesthe workability of concrete[1, 6]. Other studies [1, 6, 9- 11] have reported that the mechanical properties of the concrete with tires rubber are lower than that of the normal concrete. These studies have shown that compressive strength and splitting tensile strength of concrete with RFA are lower than that of concrete made with sand. The reduction in strength may reach up to 70% according to the replacement ratio of sand with waste tires rubber. The studies that deals with the performance of concrete made with crumb rubber in Iraq are very limited.Hence, this paper tackles the effect of using crumb rubber as fine aggregate on the workability and mechanical properties of normal concrete. The investigated mechanical properties in this study include compressive strength and splitting tensile strength.In the following sections, the experimental work, results, discussion and conclusions are described. http://www.iaeme.com/IJCIET/index.asp 1984 editor@iaeme.com Behaviour of Concrete Incorporating Tirederived Crumb Rubber Aggregate 2. EXPERIMENTAL PROGRAMME 2.1. Materials 2.1.1. Cement Portland cement type CEM Ithat meets the requirements of BS EN 197was used in current study. The chemical analysis (given by the supplier)of the cement is shown in Table 1. Table 1 Chemical analysis of the Portland cement (CEM I). SiO2 20.94 Al2O3 4.96 Fe2O3 2.92 CaO 65.9 MgO 0.78 SO3 2.8 Na2O 0.25 K2O 0.42 Na2Oeq 0.52 2.1.2. Aggregates Two types of fine aggregate were used in this study. The first one is NFA which is local river sandbrought from Khabat district in Erbil city-Iraq.It had a maximum size of4.75 mm. The second one was RFA extracted from used tires (see Figure 2). It had maximum size similar to that of the NFA.The coarse aggregate used in this study was natural roundedriver aggregate (gravel). It had amaximum size of19.5 mm.The properties of coarse aggregates used in this study are presented in Table 2. Table 2Physical properties of fine aggregates (FA) Property Shape Surface texture Specific gravity (SSD) Water absorption % Type of FA NFA RFA Angular Angular Smooth Rough 2.65 1.15 1.3 Negligible Figure 2 Recycled fine aggregate (crumb rubber) 2.2. Mix proportions and experimental work (b The total number of mixes prepared and examined in the study is four.Variables of the study, code of mixes and the mix proportions for all mixes are shown in Table 3. All mixes had the same water/cement (w/c) ratio (0.5). http://www.iaeme.com/IJCIET/index.asp 1985 editor@iaeme.com Firas F. Jirjees, Shelan M. Maruf, Ahmed R. Abdul Rahman, Khaleel H. Younis Table 3 Code of mixes, variables of study and mix proportions (kg/ m3) Mix Rubber content % Cement code Water FineAgg. (natural) FineAgg. CoarseA (crumb gg. Rubber) 0 1066 M0 0 360 180 755 M10 10 360 180 679.5 75.5 1066 M20 20 360 180 604 151 1066 M30 30 360 180 528.5 226.5 1066 The ingredients of the concrete mixtures were blended using a pan mixer with capacity of 0.08 m3. The concrete mixtures were compacted using internal vibrator. For each mix: three100 mmcubes and three cylinders 100×200 mm were prepared. Thereafter, plastic sheets were used to cover the specimens and allowed to cure for 24 hours before being demoulded. Then, they were kept in water tanks for 27 days. 2.3. Tests 2.3.1. Workability “Slump Test” The workability of all mixes was assessed using standard slump test. The test carried out following the BS EN 12350-2 [12]. 2.3.2. Compressive strength test After 28 days of curing and by following the BS EN 12390-3 [13] standard test, the cube specimens were tested for compression. Figure 3 shows the machine used for the compressive strength test. Figure 3 Compressive strength test machine 2.3.3. Splitting tensile strength test After 28 days of curing and by following the BS EN 12390-6 [14] standard test, the 100×200 mm cylinders specimens were tested for splitting tensile. Figure 4 shows the machine used for the splitting tensile strength test. http://www.iaeme.com/IJCIET/index.asp 1986 editor@iaeme.com Behaviour of Concrete Incorporating Tirederived Crumb Rubber Aggregate Figure 4 Splitting tensile strength test machine 3. RESULTS AND DISCUSSION 3.1. Workability of concrete “Slump Test” The workability of all mixes was assessed using the slump test method. The results ofall mixtures are displayed in Table 4 and Figure 5. Table 4 Results of concrete slump test with the reduction in slump values compared to the reference mix (M0) Mix M0 M10 M20 M30 Slump mm 180 140 80 30 Slump Reduction (%) 0.0 22.0 56.0 83.0 Figure 5 Effect of crumb rubber content on theslump values of concrete The results shown in Figure5 reveal that the partial replacement of sand with crumb rubber leads to the reduction in workability of concrete. The reduction in workability depends on the replacement ratio as can be seen in Table 4. Replacing sand with crumb rubber at ratios of 10, 20 and 30 % results in a reduction in the workability of concrete of 22, 56 and 83% respectively, compared to the mix without rubber (M0). Similar results were reported by [1,8]. http://www.iaeme.com/IJCIET/index.asp 1987 editor@iaeme.com Firas F. Jirjees, Shelan M. Maruf, Ahmed R. Abdul Rahman, Khaleel H. Younis This reduction in the workability could be due the surface features of the crumb rubber particles. The rough surface texture and elastic behaviour of the rubber particles are the sources for a possible increase in the friction developed between crumb rubber particles and the rest of the ingredients under the free flow [1,7]with a possible absorbing of the moving energy [1]. 3.2. Compressive strength The results of the 28 days compressive strength of all mixesare presented in Table 5 and Figure6. Each value in Table 5 is the average of 3 cubes. The table also shows the decrease inthe compressive strength (compared to that of the reference mix M0) due to the addition of the crumb rubber. Table 5 Results of compressive strength and the splitting tensile strength with the percentage decrease in the strength compared to the reference mix (M0). Compressive strength Splitting tensile strength Mix Strength MPa Strength Decrease (%) Strength MPa M0 34.2 - 4.1 Strength Decrease (%) - M10 26.1 24 3.0 27 M20 20.8 39 2.6 37 M30 12.3 64 1.2 71 Figure6 Effect of crumb rubber content on the compressive strength of concrete The general trend of the compressive strength of the mixes made with crumb rubber shows a reduction in its values as can be seen in Figure6. It can be seen that the reference mix M0 had a compressive strength of 34.2 MPa. The partial replacement of the sand with crumb rubber at ratios of 10%, 20% and 30% resulted in compressive strength of 26.1MPa, 20.8 MPa and 12.3 MPa for the mixes M10, M20 and M30 respectively. The strength degradation due to the use of crumb rubber aggregate for mixes M10, M20 and M30 are 24%, 39% and 64%respectively, as can be seen in Table 5. Similar strength decrease was also observed by http://www.iaeme.com/IJCIET/index.asp 1988 editor@iaeme.com Behaviour of Concrete Incorporating Tirederived Crumb Rubber Aggregate [7, 8, 15]. This behaviour can be attributed to the large difference between the stiffness of the crumb rubber particles and the cement paste and the lower modulus of elasticity of the crumb rubber particles compared to the particles of sand [8, 16]. This could also be due to the low density of the concrete made with crumb rubber which leads to lower compressive strength. 3.3. Splitting tensile strength Table 5 and Figure 7show the results of splitting tensile strength at the age of 28 days of all mixes. The result of each mix is the average of three cylinders. The table also shows the decrease in splitting tensile strength of mixes made with crumb rubber compared to the reference mix M0. Figure 7 Effect of crumb rubber content on the splitting tensile strength of concrete The results of the splitting tensile strength had a general trend that is similar to that of the compressive strength. It can be seen that the strength of the mixes with crumb rubber had lower splitting tensile strength than that of without crumb rubber. The reduction in tensile strength depends on the content of the crumb rubber. The reference mix M0 had a tensile strength of 4.1 MPa, whereas the mixes M10, M20 and M30 had strengths of 3MPa, 2.6MPa and 1.2MPa respectively. The decrease in splitting tensile strength due to the replacement of sand with crumb rubber could be due to the lower modulus of elasticity of the crumb rubber particles compared to the particles of sand [8,17]. Another reason could be the low density of the concrete made with crumb rubber which leads to lower tensile strength of concrete. 4. CONCLUSIONS The following conclusions can be drawn according to the experimental results:1. Crumb rubber leads to lower workability (slump) of concrete due the rough surface of crumb rubber particles aggregate and the internal friction developed between the ingredients of the concrete. 2. The general trend of the compressive strength and the tensile strength of the mixes with crumb rubber showed lower strengths compared to the reference mix (without crumb rubber). The level of the reduction in strength depends on the content of the crumb rubber. The higher the content, the higher the reduction in strength. 3. The compressive strength values of the mixes with crumb rubber decreased by 24%, 39% and 46% respectively for the mixes M10, M20 and M30 compared to the reference mix (M0 mix). http://www.iaeme.com/IJCIET/index.asp 1989 editor@iaeme.com Firas F. Jirjees, Shelan M. Maruf, Ahmed R. Abdul Rahman, Khaleel H. Younis 4. The split tensile strength valuesof the mixes with crumb rubber decreased by 27%, 37% and 71% respectivelyfor the mixes M10, M20 and M30 compared to the reference mix (M0 mix). REFERENCES [1] Najim, K.B. and M.R. Hall, “A review of the fresh/hardened properties and applications for plain (PRC) and self-compacting rubberised concrete (SCRC)” Construction and Building Materials, 24(11), 2010, pp. 2043-2051 [2] Khaleel, H.Y., et al., Feasibility of using recycled steel fibres to enhance the behaviour of recycled aggregate concrete. ACI Special Publication, 2014-July (SP310)pp. 113-122. [3] Younis, Khaleel Hassan. Restrained shrinkage behaviour of concrete with recycled materials. PhD thesis. University of Sheffield, 2014. [4] Khaleel H Younis, Harth S Naji, Khalid B Najim“Cracking tendency of self-compacting concrete containing crumb rubber as fine aggregate” Key Engineering Materials,744(55),2017,pp.55-60. [5] Khatib, Z. K., and Bayomy, F.M. (1999) “Rubberized Portland Cement Concrete” Journal of Materials in Civil Engineering, 11(3):206-213. [6] Khaleel H Younis, Harth S Naji, Khalid B Najim„‟Rheological Behavior of SelfCompacting Concrete Incorporating Crumb Rubber Particles As Fine Aggregate‟‟ The proceeding of the 3rd International Engineering Conference on Developments in Civil and Computer Applications IEC2017, Erbi-Iraq, 2017. doi: 10.23918/iec2017.08 [7] Taha, M.M, El-Dieb, A. S., Abd El-Wahab, M. A.,and Abdel-Hameed, M. E., (2008) “Mechanical, fracture, and microstructural investigations of rubber concrete” Journal of Materials in Civil Engineering, 20(10):640-649. [8] Najim, K. B. and Hall, M. R., (2011A) “workability and mechanical properties of crumb rubber concrete” Proceedings of the Institution of Civil Engineers ICE, construction Materials Journal, [9] Snelson, D.G., Kinuthia, J.M., Davies, P.A., and Chang, S.-R. 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[14] BS EN 12390-6:2009, Testing Hardened Concrete Part 6: Splitting tensile Strength of Test Specimens, British Standards Institution, London, UK, 2009. http://www.iaeme.com/IJCIET/index.asp 1990 editor@iaeme.com Behaviour of Concrete Incorporating Tirederived Crumb Rubber Aggregate [15] Hiremath, P. N., Jayakesh, K., Rai, R., Raghavendra, N. S., & Yaragal, S. C. (2018). “Experimental Investigation on Utilization of Waste Shredded Rubber Tire as a Replacement to Fine Aggregate in Concrete”. Sustainable Construction and Building Materials, 561–569. doi:10.1007/978-981-13-3317-0_49 [16] Zhuoming Chenab., LijuanLia and ZheXionga “Investigation on the interfacial behaviour between the rubber-cement matrix of the rubberized concrete” Construction and Building Materials, 291, 2019, pp. 1354-1364 [17] KunalBishtandP.V.Ramana “Evaluation of mechanical and durability properties of crumb rubber concrete” Construction and Building Materials, 155, 2017, pp. 811-817. http://www.iaeme.com/IJCIET/index.asp 1991 editor@iaeme.com