Using Scrap Tires as an Aggregate in Chip Seal - Phase II

Chip seals are one of the most cost and performance effective pavement preservation treatments commonly used in the United States. An eco-friendly chip seal pavement, in which the natural aggregate was replaced by crumb rubber obtained from scrap tires, was recently developed by the research team at Missouri S&T, creating rubberized chip seal. This project investigated and optimized the performance of rubberized chip seal under different scenarios. During this project, laboratory chip seal specimens with different sizes were prepared and tested under simulated traffic loads with different loading parameters and environmental conditions. Also, the feasibility of the implementation and performance of rubberized chip seal in the field was investigated in two different field sections. Test results indicated that a crumb rubber replacement ratio up to 50% is appropriate for low traffic roads with 0.25 gal/yd ² emulsion rate and aggregate with a low flakiness index. 100% rubberized chip seal also performed considerably better for high-speed traffic, snowplowing action, and high-temperature environments. Also, a highly reliable water film depth prediction model was proposed for conventional and rubberized chip seal. Field implementation projects indicated that using up to 50% rubberized chip seal could be successfully implemented in the field using conventional chip sealing procedures and equipment.