Microstructure Of Asphalt Modified By Waste Tread Powder Based On Molecular Simulation Technology Research And Low Temperature Performance Analysis

As a cheap material,waste tread powder is widely used in road surface modification in cold area.However,in the face of load,moisture and other factors in reality,low temperature cracking of modified asphalt pavement still occurs from time to time.At present,researchers’ understanding of the modification mechanism of waste tread powder mostly focuses on the macroscopic level.However,at the micro level,there is little research on how the modified system is constructed and how the behavior rules of the molecules are presented.Therefore,in order to overcome the problem of asphalt material damage,it is very important to explore the microstructure of asphalt modified by rubber powder.This research is based on the theory of adhesive adhesion,from the point of view of material damage.A breakthrough was made at the molecular level,and a comprehensive analysis was made on the modification behavior of waste tread powder from the micro,micro and macro levels by means of simulation and experiment.The study points out the rule of molecular behavior in the modification process of waste tread powder and systematically elucidates the micro-modification mechanism of waste tread powder asphalt.This kind of microcosm is different from those observed by instruments in the past,but is built on the molecular basis,which can be used as an important basis for future modification research.At the same time,the low temperature performance of modified asphalt was evaluated experimentally,and the key factors affecting the modification of rubber powder were found out by comparative simulation analysis.Based on the theory of adhesion failure and under the guidance of macroscopic modification mechanism,this paper adopts the combination of simulation analysis and experimental demonstration to deeply study the microscopic modification mechanism of waste tread powder.Firstly,molecular models of asphalt and rubber were established by using molecular simulation tools,and the rationality and balance of the models were judged to determine the feasibility and accuracy of the simulation method.Secondly,the microscopic properties of the molecular model were measured and analyzed,including the characteristic parameters of molecular structure,radial distribution function and glassy transition temperature.The changes of microcosmic properties of the system before and after modification were analyzed.Then,aiming at the bonding problem between asphalt and rubber,a variety of bitumen-rubber interaction models were built.Through data analysis and summary,the mechanism of modified asphalt with rubber powder was systematically divided into three parts: the generation of gel film,the generation of swelling behavior,and the construction of semi-solid continuous phase system.In order to solve the problem of adhesion between asphalt system and ore aggregate,a variety of interaction models of bitumen and ore aggregate were built to analyze the change of interface adsorption energy before and after modification.Then,combined with specific experiments.The effect of modified asphalt with waste tread powder was evaluated by low temperature quantitative testing technology of bonding and adhesion strength.Then,considering the two kinds of failure,the flexural test of asphalt mixture trabecular beam is used to demonstrate again.Finally,the micro-modification mechanism of waste tread powder modified asphalt was analyzed and summarized by comparing the simulation results with the experimental results and combining with the behavior rules of microstructure interface structure.