Experimental And Numerical Analysis For The Mechanical Properties Of Basalt Fiber Asphalt Mixture

As china’s economic development, increase the amount of cargo transport, requires pavement structure has better road performance. At present, the early damage of asphalt pavement is serious. Which seriously affect the life. Study of crack has significant engineering significance. Crack the present study, there are two main methods, one is the traditional finite element method, and the other one is the extended finite element method. In this paper, use extended finite element method for crack growth simulation analysis. In order to improve asphalt road performance, the asphalt mixture add mineral basalt fiber, fiber There are two main forms, one is short cut basalt fiber, the other is batt basalt fiber. This paper formulated dosage of0.2%of the two different forms of basalt fiber asphalt mixture.At present a large number of research is mainly focused on the experimental study of cement concrete and asphalt concrete, this thesis focuses on the research of asphalt mixture mixed with basalt fiber material. Previously numerical study is mainly aimed at the expansion of single crack, this paper researches on the symmetric crack. Pavement structure crack propagation research a little, this paper studied on pavement structure crack propagation. It is studied from the following aspects.(1) This article carry on asphalt mixture flexural strength test, through comparative analysis, discussion between is not mixed with fibers and mixing fibers, fiber morphology different on the flexural strength. It can be seen through the test of the fiber mixing asphalt mixture significantly improved flexural strength, fiber-reinforced toughened also discussed, as well as to improve the mechanism of fatigue durability.(2) The fiber asphalt mixture was carried on creep test and their test creep curve fitting, find the corresponding viscoelastic parameters. The fiber asphalt mixture fracture energy tests was carried out, the bottom middle beam specimens prefabricated6mm incision, through the three-point bending test measures the force of the mid-point and crack tip opening displacement, fracture energy is obtained. Found that the fiber asphalt mixture fracture energy significantly improved. Through the trabecular specimens trend analysis can be seen crack is tortuous extended upward through the gap between the aggregate, showed significant I crack extension.(3) By means of extended finite element method (xfem) basic theory using the ABAQUS software, carry on basalt mineral fibers mixed with asphalt crack three-point bending simulation. Symmetric crack discussed apart different distances impact on crack growth. While the pavement structure with a central crack and crack unilateral moves were analyzed. When the distance between the symmetric crack is very small, The influence on crack growth is small; When the distance between the symmetric crack is larger can lead to crack expand until the specimen breaks; when the crack between the distance is further increased, crack length becomes shorter again. When reflective crack in pavement was under the vehicle load, the crack easily extensible, road damage is more serious. When the crack offset the center farther, the effects of vehicular load is smaller not easy to crack extension, which is due to decreases bending moment.