Dynamic Viscosity Standard of High Viscosity Modified Asphalt Considering Temperature and Load Coupling Effect

Abstract

The anti-ravelling and anti-rutting performances of porous asphalt pavement are significantly affected by dynamic viscosity of high viscosity modified asphalt. Climatic and traffic conditions vary greatly due to the vast territory of China, and dynamic viscosity standard has not been recommended up to now aiming at different temperature and load conditions. The influence of high viscosity additive dosage on key property indexes was firstly analysed for asphalt and asphalt mixture, and appropriate dosage was recommended. The dynamic stability changing law of porous asphalt mixture was revealed under different temperature, load and their coupling conditions. Multiple regression relation of them was established. Finally dynamic viscosity standard was proposed considering temperature/load coupling effect. The research results show that when high viscosity additive dosage exceeds 10% for 70# base asphalt, the increasing trend of dynamic viscosity becomes slowing down. Semi-logarithmic relations of dynamic stability with ravelling loss, Marshall stability were respectively found, and double-logarithmic relation of that with dynamic viscosity was found. The appropriate dosage of high viscosity additive is recommended as 12%. Based on multiple regression formula of dynamic stability with dynamic viscosity, temperature and load, the lower limit of 60°C dynamic viscosity is recommended as 50000Pa•s for normal region, 100000Pa•s for heavy-load region, 200000Pa•s for high-temperature region, and 400000Pa•s for heavy-load & high-temperature region.