Key role of network formation in Rutting, fatigue and brittle performance of bitumen/PEG/MDI/SiO2 composites

Abstract The effect of hydrophilic SiO2 content on the rheological property of bitumen (B)/ polyethylene glycol (PEG)/4,4′-diphenylmethane diisocyanate (MDI)/SiO2 composite was investigated. The multiple stress creep and recovery (MSCR) and linear amplitude sweep (LAS) tests were applied to analyze the rutting resistance at high temperature and fatigue life at intermediate temperature of bitumious composites, respectively. The low temperature property was evaluated by glass transition temperature and tensile behavior. All the results suggested that the optimal SiO2 loading for modified bitumen with the best service performance was around 1%. The mechanism for these results was explored by the competitive and coupling effects of SiO2 nanoparticles networking themselves, polyurethane reaction between MDI and PEG, as well as urethane reaction between MDI and SiO2. The intrinsic nature of network structure played a key role in the performance of B/PEG/MDI/SiO2 composite.