Based On Dynamic Mechanical Analysis(DMA Method),the Main Curve Feature Point Of Asphalt Mixture Temperature Is Studied

Asphalt mixture as the main material of asphalt pavement has typical viscoelasticity,and the temperature change is very sensitive to the mechanical properties.In the course of service,bituminous mixtures can be repeated over and over the temperature range.In most regions of China,the temperature gradient of asphalt pavement is very different in one day,so the influence of temperature change on viscoelastic energy of asphalt mixture is not negligible.Based on the change of temperature,the main curve drawn in the whole temperature range can describe the influence of temperature change on the viscoelastic parameters.Due to the wide range of the main curve,it is difficult to apply to the actual project,and the characteristic points of the main curve of temperature are extracted from the main curve of the temperature.But because of the significance of feature points is not clear,and glassy state transformation temperature of physical meaning is clear,with the aid of the meaning of glassy state transformation temperature can get feature points and feature points is obtained in low temperature,high temperature on behalf of the value and combined with high temperature and low temperature test,to evaluate the high temperature and low temperature performance.Dynamic mechanical analyzer(DMA)was used to test the glass state transition temperature,and several evaluation indexes were obtained under the fixed temperature,frequency and strain level.Due to the large difference in the numerical value of each group of evaluation indexes,the temperature of glass transition temperature was evaluated by theoretical analysis and variance analysis.Using DMA device to complex modulus test,test to select the frequency of nine,seven temperature,got about the horizontal displacement of frequency factor,then draw the complex modulus,phase Angle and the temperature of the loss modulus master curve.According to the characteristics of the main curve,five characteristic points of the main curve of temperature are obtained.Since the lower limit of the complex modulus exceeds the actual temperature range,the remaining four feature points are selected.There is a significant correlation between the four feature points and the peak loss modulus,so the feature points can be unified.Feature points can be used in high temperature,low temperature,and can extract the feature points of high temperature and low temperature represents the value,and sort,in the midst of different asphalt mixture with high temperature and low temperature sorting result than conventional test indicators,and obtained the index of high temperature characteristic points and the dynamic stability of significant correlation,low temperature characteristic points and the index of trabecular bending compression strain energy density significantly correlated,and the expression between them,so as to evaluate the high temperature and low temperature performanceFeature points to solve the main curves due to contain too much information,it is difficult to apply the problem,and combined with high temperature and low temperature performance index between,so as to evaluate the high temperature and low temperature performance.At the same time,the feature points by using glassy state the practical significance of the transformation temperature can get feature points and feature points to get high temperature,low temperature representative value makes the feature points in the high temperature,low temperature has the practical significance.