Experimental Investigation of High Temperature Behaviour of an Asphalt Binder Modified with Laval University Silica Based on Multiple Stress Creep and Recovery Test

For experimental investigation of the high temperature behaviour of an asphalt binder modified with Laval university silica (LUS-1) nanostructured particle, four different asphalt binders were produced using a mixture of 2, 4, 6 and 8 wt% of this additive and a neat bitumen at 170 °C. The neat bitumen was yielded from crude oil refining and had a penetration grade of 85–100. After a 20 min vibration, the produced mixtures were mechanically mixed for 30 min in a high-shear homogenizer mixer with an angular velocity of 4500 rpm. Then, the modified binders and neat bitumen were subjected to multiple stress creep and recovery (MSCR) test, after the aging process in rolling thin film oven (RTFOT) test. The results of this study, which were in agreement with the results of the dynamic shear rheometer (DSR) test, indicated that LUS-1 could improve the high temperature behaviour of binders. The greatest improvement occurred using 4 wt% of LUS-1, where this improvement was more pronounced at high stress levels. Elevating the levels of stress and temperature led to diminished traffic grade and more viscous behaviour in asphalt binders modified with LUS-1.