Effects of Surface Modification of Crumb Rubber with Polyvinyl Acetate on Rubberized Concrete
Omid Aghamohammadi, Davood Mostofinejad, and Sayyed Mahdi Abtahi
Appears on pages(s):
crumb rubber concrete; durability-related parameters; mechanical properties; modification of rubber surface; polyvinyl acetate
Burning or landfilling worn tires has irreversible destructive effects on the environment. The recycling of crumb rubber in concrete not only helps to solve one of the main environmental pollutants but may also enhance concrete ductility and energy absorption. The disadvantage associated with this practice, however, is that crumb rubber weakens concrete in terms of its mechanical properties and reduces its durability because of the hydrophobicity of crumb rubber that causes weak contact between the cement paste and the crumb rubber. To improve the adhesiveness of the interface surfaces, different additives have been considered for modifying the crumb rubber surface. For the present study, some 230 samples were prepared in which crumb rubber was used to replace fine aggregate over a range of 0 to 60% (approximately 25% of total aggregates volume) and polyvinyl acetate was used as a rubber surface modifier. Investigation of the mechanical properties and durability-related parameters of concrete containing different percentages of rubber thus modified revealed that crumb rubber surface modification improves concrete compressive, flexural, and tensile strengths by up to 12 to 18%. Also, durability-related parameters were observed to improve significantly as revealed by reductions of 68% and 30% in water absorption and water penetration depth, respectively. Moreover, chloride ion penetration and carbonation depths were found to decrease by 17% and 15%, respectively. The use of polyvinyl acetate as a modifier by improving the adhesion of crumb rubber and cement paste improves the strength characteristics and prevents the penetration of water and destructive substances into the concrete, which is very important for concrete pavements.