Performance Evaluation of Bioengineered Recycled Asphalt Materials

In this study, asphalt mixtures were engineered with bio-renewable soybean oil-derived modifiers, and then used for pavement demonstration projects in the U.S. states of Iowa and Minnesota in the summer of 2019. The performance grade, elastic recovery (R), and non-recoverable creep compliance (Jnr) of the binders were evaluated. The modification of asphalt binder for the Iowa project almost maintained the high and low temperature grades, and the presence of modifier in the mixture of Minnesota project resulted in a slight decrease in the low temperature grade while maintaining the high temperature grade. The Jnr and R values proved the increase of elasticity and relaxation of the asphalt binder modified for the Iowa project. The Jnr calculated for the Minnesota project revealed a considerable increase in the relaxation of the asphalt binder. Disc-shaped compact tension, Hamburg wheel tracking, and push-pull were the mechanical performance tests performed on the mixtures. Based on the results obtained from these tests, the Iowa mixture, produced with modified asphalt binder, showed a significant improvement in resistance to low-temperature cracking, rutting, moisture damage, and fatigue cracking. The Minnesota mixture, modified in the plant, showed a significant improvement in the fatigue performance and a slight improvement in low-temperature cracking resistance.