Recycled tires as coarse aggregate in concrete pavement mixtures

This research evaluated the reuse potential of recycled tire chips as coarse aggregates in pavement concrete. Experimental investigation of modified pavement concrete, using different volume coarse aggregate replaced by tire chips, was completed to check the fresh and hardened concrete properties. One control mixture was designed for comparison. The coarse aggregate component of rubberized concrete was replaced by volumes of 100%, 50%, 30%, 20%, and 10% using tire-chips particles. The cementitious materials was changed from 660 lbs/cy to 570 lbs/cy to evaluate the performance. Two mixtures with 10% coarse aggregate replaced by tire chips had the best performance among all the mixtures and exceeded the 28-day compressive strength and flexural strength requirement of Colorado Department of Transportation Class P pavement concrete. The two mixtures showed high freeze/thaw durability in moderate chloride-ion penetration tests. Effects of using high-range water reducer and low-range water reducer were examined for mixtures with 10% coarse aggregate replacement. The rubberized concrete mixtures investigated in this study demonstrated ductile failure in compressive, flexural, and splitting tests instead of brittle failure as a control mixture.