Study On Anti-cracking Performance Of Basalt Fiber Asphalt Mixture

Pavement cracking is caused by the accumulated stress caused by temperature stress,driving load and the damage of materials exceeding the allowable level of materials.And asphalt pavement cracking,the occurrence of structural damage,serious harm to road performance and life.Therefore,in-depth study on the anti-cracking performance of basalt fiber asphalt mixture is beneficial to solve the problems of asphalt pavement cracking and other diseases,which having far-reaching significance for reducing maintenance times and extending the service life of asphalt pavement.Firstly,Marshall design method and superpave design method were used respectively to design the mixture ratio of asphalt mixture with and without basalt fiber SMA gradation and Superpave gradation,to determine the mineral composition of 10 kinds of asphalt mixture and the best asphalt ratio,and to analyze volumetric index.Secondly,the road performances of the ten asphalt mixture were tested by the rutting test,low temperature bending test,water immersion Marshall test,freezing and thawing splitting test and four-point bending test.The test results show that basalt fiber can improve the high temperature rutting resistance,low temperature crack resistance and fatigue resistance of asphalt mixture.Then,the cracking process and mechanism of ideal cracking test and semicircular bending test are deeply analyzed,and the influence of basalt fiber,asphalt binder,nominal maximum size of aggregate and aggregate grading type on cracking resistance of asphalt mixture is studied.The results show that both basalt fiber and SBS modified asphalt can significantly improve the anti-initiation performance and anti-crack propagation performance of asphalt mixture,especially the effect of adding basalt fiber in SBS modified asphalt is better;in Superpave gradation asphalt mixture,the larger the maximum nominal particle size,the lower the crack resistance;SMA gradation is better than Superpave gradation asphalt mixture in anti-initiation performance and anti-crack propagation performance.Finally,by comparing the different relations of ideal cracking test,semicircular bending test and four-point bending fatigue test to evaluate the crack resistance of asphalt mixture at medium temperature,three kinds of evaluation indexes with high correlation and their respective applications are obtained.The results show that the ideal cracking test and semicircular bending test are mainly used to evaluate the mid-temperature cracking resistance and crack propagation resistance of asphalt mixture,and the four-point bending fatigue test is mainly used to evaluate the fatigue cracking resistance of asphalt mixture;furthermore,the CTindex,FI and fatigue life(650??)are correlated to evaluate the effect of basalt fiber on the anti-cracking performance of asphalt mixture.In this paper,the anti-cracking performance of basalt fiber asphalt mixture is analyzed in depth,which provides a reference for the structure and material design of high-grade highway asphalt pavement,and has certain theoretical significance and application value.