Research Of Low-Temperature Performance On Basalt Fiber Asphalt Concrete Pavement

The asphalt concrete pavement is easy to crack under the action of temperature stress due to the harsh climate in Qinghai province,which greatly increases the maintenance cost of asphalt concrete pavement.Previous widely used lignin fiber and polyester fiber have shown a series of disadvantages,especially in Qinghai,where the temperature is low and the temperature difference between day and night is large,it is easy to produce temperature-type cracks.Basalt fiber has the properties of high fracture strength,low moisture absorption,good thermal stability and good oil absorption,so it has a broad application prospect in asphalt concrete pavement.In order to enhance the low temperature performance of asphalt concrete pavement,the optimal fiber content and fiber length were obtained through a lot of laboratory tests,which provided a theoretical basis for the application and popularization of basalt fiber in asphalt concrete in Qinghai area.In this paper,basalt fiber is used as the mineral admixture of asphalt concrete,and the following relevant studies are conducted in combination with the climatic characteristics and engineering characteristics of Qinghai region:(1)By comparing basalt fiber with lignin fiber and polyester fiber,the superiority of basalt fiber is analyzed(2)90# matrix asphalt was selected for the test,and three major indexes of matrix asphalt were tested.(3)Adopt AC-13 asphalt concrete gradation,and conduct various technical index tests on mineral materials and powder;(4)Carry out the mixing ratio test to obtain the optimal asphalt content under different fiber content and fiber length;(5)High temperature rutting test and immersion Marshall test were used to study the high temperature stability and water stability of basalt fiber asphalt concrete,and to verify the rationality of the optimal amount of asphalt;(6)Conduct three-point bending tests at 25℃,-5℃,-10℃ and-20℃ to study the low-temperature cracking resistance of basalt fiber asphalt concrete,and determine the optimal length and content of basalt fiber;(7)PFC discrete element particle flow software was used for simulation test,to analyze the generation mode of cracks and the change rule of stress-strain curve,andto explore the enhancement mechanism of basalt fiber on the low temperature performance of asphalt concrete.