Study On Viscoelastic Properties Of Matrix Asphalt At Middle And Low Temperature

Asphalt pavement with its excellent flatness fast repair performance and low maintenance costs and other advantages in many types of road stand out.Many scholars have done a lot of work in studying the road performance of asphalt mixes,but there is little breakthrough in the performance of the most basic asphalt materials that make up the asphalt mixture.Asphalt material is a sensitive material with obvious viscoelastic properties highly susceptible to temperature speed and other external factors.In recent years there are many studies on the high temperature stability of asphalt pavement and the research on the low temperature performance is very few and the most important is the low temperature road performance of substrate asphalt.Based on the theory of viscoelasticity of materials the basic mechanical properties of elasticity viscosity and viscoelasticity are reviewed.Based on the cracking mechanism influencing factors test methods and evaluation indexes the cracking of the asphalt was studied.Based on Zhenhai 70#asphalt the experimental scheme was designed and the viscoelastic parameters were studied by using the correlation analysis software.The sensitivity of the parameters was analyzed and the appropriate indexes were put forward on the basis of the existing indexes to evaluate the low temperature performance of the matrix asphalt.In order to simulate the actual working environment of asphalt pavement the dynamic shear test was carried out on the asphalt samples by rheometer.The temperature was 1°/min the frequency sweep was 1Hz-20Hz the temperature was-10??50?,The series of viscoelastic parameters of the specimen at different temperature and different frequency conditions under the cooling rate of 1 °/min Using Origin analysis software the sensitivity of its viscoelastic parameters was studied and the following conclusions were obtained:The temperature is-10?,-5?,0?,5?,10?,30?,40?,50?,the frequency of 1Hz-20Hz change through the analysis of the Han curve the asphalt is heterogeneous the asphalt viscosity,the storage modulus?the loss modulus?the rutting factor and so on and the rutting factor is more sensitive in the range of 0??10?,At the rate of 10/min and the frequency of 5Hz?10Hz and 15Hz respectively the temperature was changed from-10??50? and the viscosity was sensitive at 15Hz.The viscosity was more sensitive.The effect of the analysis analysis of the viscosity-rutting factor in the low temperature range is more sensitive.Through the regression analysis the parameters under the logarithm of temperature changes with the law,the frequency at 15Hz when the temperature of-10??10? the recommended rate of change to evaluate the low temperature performance of asphalt,and in the temperature of 10??50?compared with the existing indicators as a reference index in the temperature.