Effect of Moisture Conditioning on Mechanical Strength of Crumb Rubber Modified Asphalts

In the field of sustainability and climate resilience with respect to construction materials, this paper presents the results of an experimental campaign to study the effect of moisture conditioning on three types of crumb rubber modified asphalts. The crumb rubber modified asphalts varied in aggregate gradations, bitumen grades and percentages of different components. The three types included a stone mastic asphalt with higher bitumen content, a surface course with lower bitumen content and a warm mix asphalt. The research involved the indirect tensile testing of the asphalt samples prior to and after their exposure to various moisture conditioning treatments. Tensile strength and fracture energy, derived from load-displacement curves, were used to determine the effect of moisture on the material strength and performance. The results indicate a decrease in tensile strength as well as ability of the material to absorb energy after moisture conditionings. Freeze-thaw conditioning treatments were found to cause more damage compared to water conditioning in most samples. The fracture energy calculations indicated the toughness, cracking resistance and the ability of the materials to absorb and dissipate energy.