The Experimental Research On The Anti-reflective Cracking Performance Of Large-size Asphalt Mixture

How to restrain and prevent the asphalt overlay's reflective cracking in constructing overlays on old concrete pavement or rebuilding asphalt overlays is one of the major problems in the road construction field. Large-size asphalt mixture, one kind of flexible structures ,is of great flexibility and distortion ability ,and can be used as a stress-releasing layer which can obviously improve the pavement's ability against reflective cracking .On the other hand ,Large-size asphalt treated base can adhere well to the above asphalt concrete and the pavement structure can distribute the distress evenly because of the little difference between the two layers in modulus. So to establish a large-size asphalt treated base between asphalt overlay and old concrete pavement provides a new method to solve the problem mentioned above.This paper, concerned mainly about the comparison of several kinds of large-size asphalt mixture anti-reflective cracking performance, has mainly carried out researches on the following aspects:To expatiate the mechanism of the reflective crack formation and related influence factors, and analyze the influence of the structure of asphalt mixture on reflective cracking, which make a foundation for the function design of asphalt mixture.To analyze the features of the large-size asphalt mixture and the mechanism of strength formation and make a research on the gradation design of it .To use the drop-weight impact meter to measure the impact toughness of the asphalt mixture , put forward the use of the impact toughness as an index to evaluate the anti-reflective cracking ability.To validate the relationship between impact toughness and the anti-reflective cracking ability of the asphalt mixture ,by using the APA(asphalt pavement analyzer)which is used to simulate the fatigue life of the structure, and establish a mathematical relationship for six kinds of asphalt treated .To carry out constant-height repeated shear test on four kinds of ATPB by using the superpave shear tester ,and make a comparison between them in anti-reflective cracking ability ,which synthetically has demonstrated that ATPB-S is the best one in this aspect .