Researching on Fatigue Model of Asphalt Mixtures

Abstract

Firstly different fatigue testing methods of HMA were summarized, the scope of applicability of two kinds of control mode were analyzed,it is recommended that indirect tensile fatigue test with stress control mode to be used.Then effect of different testing factors were analyzed, the scope of the loading wave,stress ratio,frequency and temperature were selected.Three kinds of HMA specimens were compacted by gyratory compactor. Indirect tensile fatigue tests were carried by uniform test design method under different temperatures, frequencies and loadings, including three void ratios of asphalt mixes. Significance of the testing results was analyzed.The fatigue models were brought forward through multiple linear regression methods based on VFA, temperature, frequency, initial strain and initial modulus for general and heavy-duty loading. Comparative study of the fatigue models was made at home and abroad, it is shown that the fatigue models are comparable.They could be used for the fatigue prediction of asphalt mixtures. In order to study the mechanism of fatigue cracking and reduce the fatigue failure of the pavement, researchers of dif- ferent countries used different methods and proposed differ- ent fatigue models of asphalt mixtures . But these models were obtained by different experimental methods, different experimental conditions and different parameters, each of them has its specific application scope. In order to understand and master the fatigue law of as- phalt mixtures, three kinds of asphalt mixtures including AO 25I,AO20I and AK-16A were used,and fatigue testing was conducted under different conditions, then the fatigue model of asphalt mixtures was obtained.