Evaluation on Rutting Resistance and Performance of Compound Modified Bio-asphalt Based on Viscoelastic Analysis

To address the high temperature rutting resistance and performance improvement of waste cooking oil (WCO) based bio-asphalt, the organic montmorillonite (OMMT) was selected as the compound modifier to improve the high temperature performance of bio-asphalt. The multiple stress creep recovery test was utilized to quantify the influence of bio-oil and OMMT content as well as aging level on the non-recoverable creep compliance (J_nr), aging sensitivity and stress sensitivity of various asphalt binders. Viscoelastic rheological parameters of the tested binders were also fitted from the four coefficients Burgers model. Test and analysis results show that the addition of WCO based bio-oil significantly reduces the high temperature rutting resistance of petroleum asphalt under various aging conditions. The further compound Bio/OMMT modification can reach the similar rutting resistance level of petroleum asphalt, in which the performance improvement is still effective after the short-term and long-term aging. The aging sensitivity of the bio-asphalt slightly increases when compared to the petroleum asphalt. Further, compound OMMT modification into bio-asphalt also shows an overall increasing trend of the aging sensitivity. The effect of bio-oil on the binder stress sensitivity at high temperature is much lower than that of the OMMT content and aging effect, and the use of high OMMT content should be limited from the stress sensitivity requirement. Additionally, the fitting results of four coefficients Burgers model show that the use of bio-oil modification decreases the proportion of elasticity and delayed elasticity in creep compliance but increases the viscous part. Meanwhile, the further OMMT compound modification displays the completely opposite impact on the creep compliance proportion of the bio-asphalt.