Research On Interlaminar Shear Fatigue Performance Of Pavement Asphalt Mixtures

The interlayer bonding quality is one of the most important factors affecting the service life of asphalt pavement, especially in large longitudinal slope sections, small radius and accelerate the braking area of asphalt pavement, the pavement structure layer will produce horizontal loads, When the load exceeds a certain number of times, shear stress within the pavement structure will exceed the inter-layer shear strength values after attenuation, making the asphalt pavement layer between the shear fatigue damage. Recently, due to a new type of double-paving technology has significantly improved inter-layer adhesion performance advantages. However, almost all research about this technology were center on introduction and implementation, did not study fatigue properties of this technology. Based on this, this paper studied the interlaminar shear fatigue test of the two pavement paving the way, in order to analyze the fatigue performance of the two paving mode.Firstly, this paper has carried on the investigation of asphalt pavement of Jiangxi Chang-jiu high-speed national highway and 318 State Road from Luo-dang to Fen-shui section, analyzed the existing pavement diseases and the causes of disease. The results show that: Pavement distress was related with the fatigue failure under the repeated wheel loads, ruts and cracks almost appeared along with inter-layer interface slip, or even rupture.Secondly, interlaminar shear strength and interlaminar shear fatigue test were carried out by the 45 degree oblique shear tests, analyzed the interlaminar shear properties and the shear fatigue performance. The results shows that: the interlaminar shear fatigue test data reflects the good trend in three stages. This illustrate that the interlaminar shear fatigue test can link the asphalt performance indoor and actual road performance, and clearly explain the permanent deformation of asphalt pavement layer interface. Analyzed three indicators of the fatigue life, interlaminar shear modulus and shear deformation rate, considered that the fatigue life just simple react the numerical value, did not reflect the relevance between the fatigue properties and the material properties; Interlaminar shear modulus changes with loads exist three stages change trends of the three stages of the existence of trends change with loads between layers, but not all of the asphalt mixture specimen will be significant inflection point, therefore, to represent the shear fatigue properties by interlaminar shear modulus still need more tests to proving. Stable phase between layers increases with the number of loads shear deformation(ND1)basically layer linear increase, calculated that the ND1 is a more stable parameter can be used to characterize the asphalt of the interlaminar shear fatigue performance.Finally, to determine the bonding state between layers is described by using Bisar3.0 software, and verified by laboratory tests, that between0~2,as the interface between layers in the bonded state better, and between the upper layer and the surface layer bonded to stress the lack of asphalt layer bottom generated, will not produce fatigue crack bottom; and the fatigue life of the deflection control mode interlaminar shear stress than in control mode the fatigue life of more than 50 times. Therefore, the design does not consider the impact of the asphalt pavement interlayer shear stress is very safe.