Compressive Strength of Rubberized Concrete - Assignment Example

Compressive Strength of Rubberized Concrete Professor’s Name University The City and State Date Compressive Strength of Rubberized Concrete Car tyre rubber has increasingly been used as a replacement of natural aggregates for producing concrete. This has come due to the rising need for sustainable ways to dispose of worn out or waste tyres. Currently, rubberized concrete has been used widely especially in non-structural constructions such as sidewalks and pavements. This has produced a wide range of research literature surrounding the engineering properties of rubberized concrete. One of the main areas that rubberized concrete literature has focused on is the compressive strength properties. Compressive strength is the resistance or inability of a substance to breaking while under compression or increased density. A wide range of literature has supported the fact that the compressive strength of rubberized concrete decreases as the percentage of rubber aggregate increases. Nonetheless, the reasons behind the loss of compressive strength are non-linear across literature. The following literature review aims at investigating the compressive strength properties of rubberized rubber. It is argued that the compressive strength of rubberized rubber will reduce as the rubber aggregate percentage increases based on the differences in size, shape, type, and origin of rubber aggregates. In a research article by M.MAVROULIDOU et al. (2010), the compressive strength of rubberized concrete (both fine and coarse) was tested using the Losenhausen (3MN) compression device based on BS EN 12390-3:2002m specifications (British Standards Institution (BSI), 2002). The research findings illustrated the relationship concerning regular cube compressive strengths and the rubber aggregate percentage from 7 to 28 days of the curing process (see figure 1). The findings of the study illustrate a substantial reduction in compressive strength based on the regular outcomes of the control mixtures. Moreover, as illustrated in figure 1, compressive strength reduced further as the rubber aggregate increased in percentage of the mixture. Figure 1 Compressive strength variation with rubber content. Compressive strength was reduced to 94% of the concrete mixture when rubber aggregate content was increased to 40% as illustrated in table 1. This supports the arguments that compressive strength is reduced as the percentage of rubber aggregate increases. Furthermore, the research also concluded that rubberized concrete with coarse rubber illustrated a higher compressive strength when compared to concrete with finer rubber. The same findings are also supported by Fattuhi & Clark (1996), who found that concrete with coarse rubber illustrated a higher compressive strength of about 10% than concrete with finer rubber. Besides, the findings of the study also illustrate minimal increase in compressive strength in concrete with rubber aggregate from the 7th to the 28th day of curing with the exception of the 10% coarse aggregate mixture that is also consistent with Eldin & Senouci’s (1993), research findings. Curing time (days) Compressive strength loss  coarse rubber aggregate (CRA) fine rubber aggregate (FRA) 10% 20% 30% 40% 10% 20% 30% 40% 7 53% 76.6% 87.5% 94.3% 32% 60% 82.1% 89% 28 60.8% 77.9% 89.6% 92.6% 40.9% 68.3% 81.8% 88.3% Table 1 Average compressive strength loss for mixes containing rubber aggregate. The reduction in compressive strength or ability to resist density is true especially for the finer rubber. The research by Eldin & Senouci (1993), concluded that the fine rubber concrete mixture illustrated an exponential reduction of strength with the increase of density as illustrated in figure 2. A clear indication is that compressive strength reduces substantially once the rubber aggregate especially finer rubber is increased to over 20% in the contrite mixture. The implications of the two studies is that based on the findings, the rubberized concrete may not be suited for structural uses where there is high demand for compressive strengths. Nonetheless, mixtures with 10% or 20% rubber aggregates could possibly be used for construction in areas where demand for compressive strength is low such as driveways and sidewalks. Figure 2 compressive strength variation with density The main limitation of literature surrounding rubberized concrete is based on the varying sizes, shapes, origins, and mixture rates used in investigating the compressive strength (see figure 3). Moreover, it is evident that the compressive strength of concrete is the main engineering property that be influenced by suing rubber aggregate as a substitute for natural aggregates such as sand. However, it is consistent in all literature that the compressive strength of concrete reduces as the percentage or amount of rubber aggregate is increased. However, there are varying explanations as to how or why the compressive strength reduces as rubber aggregate increases. A review of numerous literatures can help in understanding the varying relations and explanation of rubber and concrete. The main assumption is that rubber particles are assumed to be vacuums since they have no adhesion properties or abilities between the rubber and cement particles. A research by Khatib & Bayomy (1999), suggested that the reduced exact gravity of rubber atoms matched to cement particles or mixture leads to cracks around the rubber atoms to arise rapidly when compression is applied, which increases the failure of the mixture. In addition, Chou et al. (2007), argued that the reduction in compressive strength was attributed to the varied, water-resistant rubber particle features that resulted to local inadequacies in terms of hydrating cement, thus resulting in its reduced ability to resist compression. This assertion has been supported through microscopic research literature illustrating that rubber particles dispersed water transfer in the mixture to develop passages vulnerable to cracking, consequently resulting in loss of strength. Based on un-applicability of rubberized concrete with over 20% of rubber aggregates, the following sections will focus on literature that conducted tests on rubberized concrete with only 10% of rubber aggregates of different sizes, types, and origins. This is because the 10% rubber aggregate concrete illustrates higher values in terms of compressive strengths and in engineering application. Figure 3 Different type of rubberized concrete compare with no rubber concrete. As proposed in the beginning, Youssf, et al. (2014), study also illustrates an important relationship between accumulative rubber aggregate content and loss in compressive strength. The findings of the study illustrated that compressive strength reduced to 70% when the rubber content was increased to 25% (see figure 4). The article attempts to explain the reduction in numerous approaches. Firstly, it is noteworthy that great internal tensile pressures vertical to the direction of the weight can lead to early failure in cement. Again, rubber and cement are originally or traditionally incompatible and is considered as under-mixing, thus the exposure to reduced compressive strength. Another finding from the study is that the reduced permeability of rubber particles substantially damages the interaction between the borders of cement paste and rubber particles, thereby enhancing the capacity of the weakest stage and inter-facial changeover zone. The study clearly supports that compressive strength of rubberized concrete decreases as the rubber content surges. The study concludes that the use of other aggregates such as SBR Latex and a 40% substitution of sand aggregate can be used as means of enhancing the overall compressive strength of rubberized concrete for structural engineering applications (Youssf, et al. 2014). Figure 4 The compressive losses based on percentage of rubber content increasing (Youssf, et al. 2014). Additionally, research by Er.Yogender (2014), tested the influence of crumb rubber on compressive strength of concrete. As illustrated in figure 5, the findings of the study observed that application of crumb rubber also reduced concrete compressive strength, which is based on increasing rubber content as previously suggested. A detailed analysis of the figure illustrates that adding crumb rubber to 10% in cement showed a straight correlation between the increase of rubber and loss of strength, indicating a 24% loss in strength with the 10% increase in rubber aggregate. The implications of the study illustrate a limited use of the concrete mixture when its strength is the prime necessity for application. Figure 5 Variation of compressive strength at 7 and 28 days v/s percentage of crumb rubber as replacement for FA. Another research literature by Rui (2013), tested the compressive strengths of nine different mixtures. The results of the study are represented in table 2 and figure 6. Based on the results, the mixtures with reduced rubber content illustrated higher strengths of compression and even higher results for mixtures with coarse rubber content. This supports earlier literature that the use of coarse rubber has a higher compressive strength than the use of finer rubber or tire chips. Moreover, the same observation was made in terms of increasing tire chips or rubber content in relation to the increased reduction of compressive strength between the 21 days of curing. Overall, there is a considerable limitation in the literature based on the different types and sizes of rubber contents used. Mixture Identification 3-day (psi) 14-day (psi) 28-day (psi) 1 0Tire_660 5335 6383 7058 2 100Tire_660 392 370 515 3 50Tire_660 1146 1139 1421 4 30Tire_660 1668 1813 2371 5 10Tire_660_1 2932 3419 4835 6 10Tire_660_2 3699 3913 4614 7 20Tire_660 2194 2305 2408 8 30Tire_570 475 912 860 9 10Tire_570 475 580 1064 Table2 Figure 6 Effect of tire chips Content on compressive strength. In conclusion, the literature reviewed has supported the view that the compressive strength of rubberized rubber will reduce as the rubber aggregate percentage increases based on the differences in size, shape, type, and origin of rubber aggregates. The main reason for this is the inability of rubber particles to properly attach on to cement paste due to their non-adhesion properties. Moreover, rubber particles also have hydrophobic properties that limit the channels of water distribution in cement resulting in increased vulnerability to failure. Overall, these studies are limited in terms of the type, shape, size, and origins of rubber used. Most of the literature has supported the use of rubberized concrete for non-structural applications such as constructing sidewalks and driveways. References British Standards Institution (BSI) 2002, BS EN 12390-3:2002: Testing hardened concrete —Part 3:Compressive strength of test specimens, BSI, London. Chou L.H., Chun-Ku L, Chang J-R, & Lee MT 2007, Use of waste rubber as concrete additive, Waste Management Research, vol. 25, no. 1, pp. 68-76. Eldin NN & Senouci AB 1993, Rubber-tire particles as concrete aggregates, ASCE Journal of Materials in Civil Engineering, vol. 5, no. 4, pp. 478-496. Er. Yogender, A 2014, An Experimental Study on Rubberized Concrete, Compressive strength, Available at: http://www.ijetae.com/files/Volume4Issue2/IJETAE_0214_50.pdf [Accessed 8 June 2016]. Fattuhi NI & Clark LA 1996, Cement-based materials containing shredded scrap truck tyre rubber, Construction and Building Materials, vol. 10, no. 4, pp. 229-236. Khatib ZK & Bayomy FM 1999, Rubberized Portland cement concrete, ASCE Journal of materials in civil engineering, vol. 11, no. 3, pp. 206-213. M.MAVROULIDOU & J.FIGUEIREDO (2010), DISCARDED TYRE RUBBER AS CONCRETE AGGREGATE: A POSSIBLE OUTLET FOR USED TYRES. Available at: https://www.researchgate.net/publication/276025229 [Accessed 8 June 2016]. Rui L 2013, Recycled tires as coarse aggregate in concrete pavement mixtures. Available at: https://www.codot.gov/programs/research/pdfs/2013/rubberconcrete.pdf [Accessed 8 June 2016]. Youssf, O., ElGawady, MA, Mills, J.E. & Ma, X., 2014. Prediction of crumb rubber concrete strength. 23rd Australasian Conference on the Mechanics of Structures and Materials (ACMSM23), vol. I, pp. 261-266. Read More