Experimental Study On Performance Of Mixed Length Basalt Fiber Asphalt Mixture

The high-grade highway plays an important role as the backbone and pillar in the comprehensive transportation network of our country.The rapid increase of overloaded vehicles leads to the early damage of highway asphalt pavement,which is increasingly serious in the development stage of highways in various countries.Therefore,in-depth study of the performance of the mixed length basalt fiber asphalt mixture is conducive to solve the problems such as cracks and other diseases of asphalt pavement,which is of far-reaching significance to improve economic benefits,reduce maintenance times and extend the service life of asphalt pavement.In this paper,Superpave-13,superpave-20 and Superpave-25 are designed by Superpave design method.The mineral composition and the best oil stone ratio of the three gradations are determined.The best oil stone ratio of Superpave-13,20 and 25 is 4.7%,4.3%and 4.1%respectively,and the best oil stone ratio after adding basalt fiber is 4.8%,4.4%and 4.2%respectively.In order to determine the best single mixing length of basalt fiber in the three Superpave graded asphalt mixtures,the routine performance test was carried out by laboratory test.The test results show that the performance of Superpave graded asphalt mixture can be improved obviously by adding basalt fiber.The basalt fiber with the length of 6mm,9mm and 12mm is better for Superpave-13,20 and 25.The digital image processing method is used to obtain and process the internal structure information of the mixture.The relationship between the performance of basalt fiber asphalt mixture and its micro structure characteristics is studied by the indexes such as the section void ratio and the main axis length of asphalt mortar.The research results show that the best single mixing length and the proportion of basalt fiber are obtained from the micro structure analysis and the test The results are consistent with each other,and then realize the mutual verification of macro performance test and micro structure of asphalt mixture;the 2.36mm mesh passing rate has a significant impact on the main axis length of asphalt mortar in the mix proportion design,and initially establish the relationship between the micro structure characteristics of asphalt mixture and the passing rate of graded mesh.The digital image processing method is used to obtain and process the internal structure information of the mixture.The relationship between the performance of basalt fiber asphalt mixture and its micro structure characteristics is studied by the indexes such as the section void ratio and the main axis length of asphalt mortar.The research results show that the best single mixing length and the proportion of basalt fiber are obtained from the micro structure analysis and the test The results are consistent with each other,thus realizing the mutual verification of macro performance test and micro structure of asphalt mixture;the 2.36mm mesh passing rate has a significant impact on the main axis length of asphalt mortar in the mix proportion design,thus affecting the proportion of basalt fiber.This study can provide technical support for the design of basalt fiber asphalt mixture,which has certain theoretical significance and application value.