Study On Permanent Deformation Of Asphalt Mixture

Gravel is widely distributed in China,but it is not widely used in pavement construction,mostly used in the road base and subbase.The study of applying gravel to asphalt pavement surface is still in its infancy.Gravel belongs to acid aggregate and has poor adhesion to asphalt.The application of gravel directly to asphalt pavement surface will lead to serious water damage on asphalt pavement,and then reduce the service life of pavement.Basalt fiber has excellent mechanical properties,can effectively improve the adhesion between gravel and asphalt,delay the occurrence of pavement water damage and other diseases,and improve the performance of asphalt pavement.Therefore,in this paper,the basalt fiber is added to the gravel asphalt mixture to improve the adhesion between gravel and asphalt,and to enhance its road performance.In this paper,the mix ratio design and road performance of basalt fiber reinforced gravel asphalt mixture are studied,so as to give full play to the advantages of basalt fiber and gravel material.In this paper,the basalt fiber gravel asphalt mixture is studied as follows:(1)The value of the physical and mechanical properties measured gravel material test and test basket through Losangeles abrasion test,crushing,and analyzed the method of improving the adhesion between asphalt and gravel,and combined with the performance index of the pavement and recommended the method of adding basalt fiber.(2)Through the basket precipitation and sinker shear test and DSR dynamic shear rheological test respectively to determine the optimal size and the optimal amount of basalt fiber.(3)Through the design of Bailey gradation of basalt fiber gravel asphalt mixture,and to determine the optimum asphalt content under different basalt fiber ratio and the optimum asphalt content by Marshall test,and obtained the relationship between basalt fiber dosage and Marshall test indexes.(4)The gravel asphalt mixture of different basalt fiber dosage material rutting test,beam bending test,immersion Marshall test and freeze-thaw splitting test on high temperature properties of basalt fiber and gravel asphalt mixture low temperature crack resistance and water stability were studied.The results of this study showed that the basalt fiber can effectively improve the high temperature stability of gravel asphalt mixture,low temperature crack resistance,water stability and other pavement performance,and can be used on the surface layer in asphalt pavement.