Effect of elevated temperatures on physical and mechanical properties of recycled rubber mortar

Abstract The use of vehicles generates a large amount of rubber waste tires. The accumulation of rubber wastes in landfills pollutes the environment and natural resources. The valorization of rubber wastes in cement-based materials such as construction aggregates neutralize their harmful effects on the environment. Nevertheless, their sensitivity to temperature effect, constitute a major obstacle for reuse in cement-based materials exposed to temperature effect. The main objective of this work is to investigate the sensitivity of rubber mortars to temperature effect. For different mortar mixes: a control mortar (MC) made with natural dune sand and three other mixes obtained by a partial replacement with a rate of 3, 6 and 9% of sand with the same mass of RRA. The mortar specimens were subjected to four successive cycles of heating-cooling at temperature ranges of 150, 200, 300 and 400 °C. After cooling down at ambient temperature (20 ± 2 °C), the sensitivity of specimen is evaluated by the stability of their physical and mechanical properties at different thermal exposures and then compared with the control mix. The results of this study have showed that the mortar containing the RRA higher than 3% is sensitive to elevated temperatures. Until this limit, we can use the RRA in cement-based materials safely, without any risk of their combustion in case of fire. Consequently, this practice provides a clean process to eliminate the rubber waste tires which reduces their harmful effects on the environment.