Waste Tire Granular Modification Using Gamma Radiation as Concrete Aggregate

Automotive waste tires are a serious and complicated issue because it is difficult to degrade in the environment, cannot be reshaped (thermosets), and are difficult to recycle. The aim of this work is to study the effect of granular modification of waste tires using gamma radiation as a concrete aggregate. Tire granular 4 mesh (≤ 4.8 mm) is exposed by varied gamma radiation doses (20, 40, and 60 kGy). Gamma radiation effect on tire granular is identified through the functional groups, cross-link density, and density. Cubical concrete (15 cm) is molded by mixing raw materials such as cement, sand, gravel, water, and tire granular in various content. Dry concrete (6 days curing) is hydrated in water for 1 day to determine the water absorption. Concrete at 7 days curing is measured the compressive strength using compression testing machine. The result shows exposing gamma radiation at 40 kGy can increase the crosslink density of tire granular, which indicates polymer crosslinking is successfully achieved. Concrete K100 with irradiated tire granular at 40 kGy gives compressive strength improvement 150% (104 kg/cm2) compared to non-irradiated tire granular (69 kg/cm2). Even though concrete with irradiated tire granular gives lower compressive strength compared to concrete without tire granular, concrete with irradiated tire granular optimum content (4%) are still fulfill standard of SNI 03-0349.