Study On Anti-cracking Performance Evaluation Index Of Modifided Asphalt Mixtures For Stress Absorbing Layers At Low Temperature

At present,according to stress absorded layer in inhibiting compound road surface crack reflection,had excellent performance,but at anti-cracking performance evaluation of the special modified asphalt mixture with stress absorbed layer at low temperature has not mature method.The text based on the analysis of low temperature test method of asphalt mixture applicability,Considered the stress absorbed layer structure and material of the particularity,Proposed direct tensile test and semi-circle bending test (SCB),conducted the low temperature anti-cracking performance evaluation,which of the evaluation index are stiffness,collapsing strength,fracture energy preliminarily.This text used the finite element numeriacl analysis method,established the three-dimensional finite element model of semi-circle bending test,determined the experiment parameters of test,analysised specimen geometric dimensioning and test factors on the notch bottom of semicircle specimens of tensile stress influence,confirmed the test parameters of SCB test;meanwhile,direc tensile test scheme was designed,analysis of the test conditions and material parameters on the effect of two kinds of test methods, found that:two kinds of test methods to evaluate its performance were basically the same,which of them had some relevance.Based on the above two kinds of test methods of results, analysis loading method difference,the test data of discreteness,the sensitivity of evaluation index,difficulty level of the specimens molding,evaluation indexes's rationality.The research indicated that the discreteness of direct tensile test were less than that of SCB test,the experimental results were more sensitive to test conditions and material parameters.It was illustrated that the dirct tensile test could be better evaluated stress absorbed layer mixture than SCB test in low temperature.Finally,determined to use the direct tensile test to evaluate the anti-cracking performance of asphalt mixture with Stress Absorbing Layers at Low Temperature,and stretch destroy deformation work as the evaluation indexes.