Based On Repeated Creep And Recovery Test Of Asphalt High Temperature Performance Evaluation Index Research

The damage of the early stage for Asphalt Pavement in our country is serious, which Rutting is one of the main ways for road damage. This is mainly due to lack of capacity of high temperature deformation resistance for asphalt pavement. The rheological property of the asphalt binder plays a vital role on the pros and cons of the road high temperature performance. Therefore, many researchers began to focus on the asphalt combined materials with high-temperature performance, and critical analysis on applicability of high temperature performance evaluation of combined material.This report selects six kinds of representative asphalt, including two kinds of asphalt and four kinds of modified asphalt. From the point of view on asphalt research combined with material of high temperature performance, for the six kinds of asphalt, conduct separately routine test, dynamic shear test, and repeated creep recovery test. The research study on rheological properties of asphalt, compare to domestic and foreign common asphalt high temperature performance evaluation and also compare to effect of the asphalt combined material’s wheel grinding rutting test, explore the pros and cons of the different indicators of high-temperature, the study summarize the following finding:(1) Performance evaluation of conventional asphalt high temperature softening point is TR&B, when Equivalent softening point T800and dynamic viscosity ηat60℃in the high temperature performance of the pros and cons of the evaluation of modified asphalt, the result inconsistent. Conventional test results showed that lgP-T is more in line with form of quadratic curve lgP=DT2+ET+F. Good correlation of PI and (2) Superpave asphalt high temperature performance evaluation indicators include rutting factor G*/sin8and its optimization index and these rutting resistance factor critical temperature of TG*/sin8and improved resistance to rutting factor G*/(sinδ)9. Dynamic shear test results showed that the dynamic rheological parameters G’, G’, G*, and8and G*/sinδ and temperature, aging and other factors significantly associated, conventional asphalt and modified asphalt trends differently. Short-term before and after aging, asphalt PG high temperature decrease1to2grade, compared with ordinary asphalt, downgrade of modified asphalt is more obvious. TG#/sinδ doesn’t fundamentally solve problems of high-temperature indicators of PG classification, can only be as a point of reference. Use G*/(sin8)9instead of G*/(1-1/sin8·tgδ) as the optimization index is more reasonable.(3) Repeated creep recovery test results show that Asphalt creep compliance, strain, stress level, time, temperature and other factors affect and constraint each other in the way of complicated but with obvious rules. Because of its unique delayed elastic properties, for the aspect of rheological properties, modified asphalt is not the same as ordinary asphalt. Asphalt high temperature performance evaluation index obtained for European countries through repeated creep recovery test, Zero shear viscosity ZSV has limitation in practical applications.(4) It analyzes the correlation of each index and high temperature performance of asphalt mixture via Indoor60℃rutting test. Analysis of the Rutting test results illustrates that in the high temperature asphalt performance evaluation indicators, the optimal index is the creep stiffness, viscous composition Gv. It is suggested to use the result at60℃and120Pa, followed by the cumulative strain、Superpave and its optimization indicator. Because of the calculation methods and other reasons, availability of ZSV is not high. During these conventional indicators, the indicator60℃dynamic viscosity and T800could play a reference role in the evaluation of asphalt high temperature performance.