Durability and microstructure properties of SBR-modified concrete containing recycled asphalt pavement

Abstract

The road and building industry are the largest material consumers of the earth and the largest producer of solid waste. Recycling and reusing waste materials such as construction and asphaltic waste is one of the practical remedies in order to reduce the consumption of mineral materials. In this study, the effect of silica fume, styrene butadiene rubber (SBR) latex, and recycled asphalt pavement (RAP) on the mechanical properties (compressive, flexural and splitting tensile strength, module of elasticity and toughness), permeability characteristics (water penetration depth, rapid chloride ion penetration, electrical resistivity) were assessed. Additionally, microstructure properties were investigated via scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). In this regard, 33, 66 and 100 wt% of coarse aggregates were replaced by RAP. Furthermore, three different curing methods were applied to evaluate the mechanism of latex effect on compressive strength of mixtures. The results showed that the replacement of SBR latex and silica fume led to a significant increase in mechanical properties and reduction of the permeability of concrete mixtures. The interfacial transition zone (ITZ) between the cementitious matrix-aggregate using SEM images indicated that mixtures containing SBR latex and silica fume had a uniform structure at the cementitious matrix-aggregate interface. EDX analysis also indicated the reduction of ITZ thickness and the calcium to silica ratio. It was also found that the compressive strength of the concretes cured in high temperature condition increased remarkably, which exhibits the heat contribution to the formation of a polymer membrane in specimens with latex.