Study On The Mechanical Properties Of Graded Aggregate Base Asphalt Pavement

The semi-rigid base course asphalt pavement structure has been mostly adopted in China. But it is prone to producing shrinkage cracks under change of temperature and moisture content. These cracks may lead to appear reflective cracks in asphalt layer and induce other distresses. In view of this condition,this paper researched the graded aggregate base asphalt pavement and the semi-rigid base course asphalt pavement with graded aggregate upper base course.Based on dense framework type grade provided by specifications,it optimized the framework structure by stuffing theory and tested the performance through CBR and rutting test.It also studied the effect of fly ash.The results show that the designed grade has good performance.Fly ash can improve the flowability,cohesiveness and water retention of graded aggregate.According to dynamic triaxial test,it analyzed the influence of confining pressure,eccentric compression,grade,water content.It studied the shear strength and resistance to permanent deformation of graded aggregate. The results show that the dense framework type is better than the suspension dense type in modulus, shear strength and resistance to permanent deformation.The higher confining pressure is,the better graded aggregate will perform.By choosing different structure parameters,it maked mechanical analysis of the graded aggregate base asphalt pavement and the semi-rigid base course asphalt pavement with graded aggregate upper base course through KENLAYER. The results show that the thickness of asphalt layer influenced the force in structure layer very much.In terms of the mechanical analysis,it maked respective requests to the different structure materials based on performance. It proposed the design method for asphalt pavement with the tensile strain at the bottom of the asphalt layer,the compression strain at the surface of the subgrade, the tensile stress at the bottom of the semi-rigid base course as indexes.It suggested allowable standards for different traffic grade.On the basis of testing road,it studied the construction technology and method of quality control for graded aggregate.