Research On Mechanical Performance Of Asphalt Pavement With Unbound Aggregate Composite Base

With the semi-rigid asphalt pavement being widely used in china, reflective crack of semi-rigid asphalt pavement has become the focus of attention of the researchers. Using asphalt pavement with unbound aggregate composite base can be a good prevention of reflective crack of semi-rigid asphalt pavement. Based on this, the mechanical performance was analyzed in this paper, in order to provide some guidance for further promotion and application of asphalt pavement with unbound aggregate composite base.At first, on the basis of unbound aggregate material properties analysis, the mechanical nonlinear of unbound aggregate was analyzed in this paper. And in accordance with the mechanical nonlinear constitutive model of unbound aggregate in previous studies, divide it into elastic and inelastic nonlinear constitutive model. Then analyzed the material and grading of unbound aggregate.Based on the elastic nonlinear constitutive model of unbound aggregate, KENLAYER nonlinear analysis program was selected to analyze the mechanical nonlinear properties of asphalt pavement with unbound aggregate composite base. Then calculate and analyze the influence of material parameters on the mechanical performance. And determine the material parameter which has the greatest impact on the mechanical performance. Then compare the mechanical performance of asphalt pavement with unbound aggregate composite base with that of semi-rigid asphalt pavement, further demonstrate the rationality of asphalt pavement with unbound aggregate composite base.Based on the inelastic nonlinear constitutive model of unbound aggregate, ABAQUS finite element analysis program was selected to analyze the mechanical performance of asphalt pavement with unbound aggregate composite base. And analyze the effects that elastic modulus and thickness of unbound aggregate have on the pavement. Prepare the results with that of elastic nonlinear analysis, find that the results of the two analytical methods were the same.At last, based on the fracture mechanics, introduce the stress intensity factor of reflective crack as an important indicator of crack resistance of asphalt pavement with unbound aggregate composite base. Then use ABAQUS finite element analysis program to establish asphalt pavement with unbound aggregate composite base with crack model and semi-rigid asphalt pavement with crack model. Calculate the stress intensity factor of reflective crack of the two models. Find that the stress intensity factor of reflective crack of former is significantly greater than that of the latter, thus it proves asphalt pavement with unbound aggregate composite base can prevent the reflective crack very well. Meanwhile, by changing the thickness and elastic modulus of unbound aggregate, analyze the influence of unbound aggregate parameters on the stress intensity factor of reflective crack of asphalt pavement with unbound aggregate composite base.