No abstract

The present study investigated the effect of reused rubber particles (RRP) on the deicer salt durability of ordinary concrete. Four mixtures were designed, a control concrete (CC) and three other rubber concretes obtained by partial substitution of natural dune sand aggregate with reused rubber particles with 0%, 3%, 6%, and 9% w/w. All studied concretes were subjected to the combined effect of freeze/thaw (56 and 120) cycles with the deicer salt solution of 3% NaCl. The results indicated that RRP improved the deicer-salt scaling resistance of rubber concrete strongly compared with the control. The observed innovative property of RRP could be applied to cement-based materials to improve their deicer salt durability. Further, this environmentally friendly practice could reduce the stock of waste tires and offer a renewable source of construction aggregates.

The influence of rubber aggregate of tire waste (RATW) under cyclic freezethaw attack of concrete was studied. Various concrete mixes were prepared: a plain concrete (PC) produced with natural sand and rubber concretes (CRATW) included the RATW ratios of 5, 10, and 15 % such as a partial replacement with the natural sand aggregate (NSA). After the samples exposed to the different freeze-thaw cycles (120, 240, 340), their following properties were evaluated: visual observations, mass loss, dynamic modulus of elasticity and compressive strength. Our results indicate that the inclusion of RATW increasing entrappedair and the interfacial transition zone (ITZ) between cement matrix -rubber is weak and porous. In addition, the rubber concretes have higher resistance to freeze-thaw attack compared to plain concrete. This innovative trend could be extending the concrete structures' life in a cold climate. This clean practice of reusing RATW with cement based materials will reduce their stock in the landfills and eliminates their pollution on the environment.

This study investigated the chemical compatibility of recycled rubber powder "RRP" with Portland cement by hydration test. Four mixes were prepared: pure cement paste and three rubber -cement pastes included 10%, 20%, and 30% of RRP. The compatibility of rubber -cement paste was evaluated by their temperature-time curves. The results of aptness and inhibitory index have shown that RRP rates higher than 10% was strongly inhibited the hydration reaction of cement. In addition, the setting time results revealed that rubber mixes require a longer curing time than pure cement paste, so the RRP could be used with cement-based materials as a setting retarder admixture. The recycling of rubber tire waste with cement-based materials could be reduced their accumulation in landfills and protects the natural and environment facing their harmful effects.