| In recent years, mainly due to traffic growth in China, a large proportion ofheavy vehicles, the traffic situation is increasingly serious, with the growth of theage of the road, part of the semi-rigid asphalt base pavement structure appearvarious diseases and wherein cracks as the main form of the disease. Themaintenance of the primary disease is one of the problems in highway maintenanceand repair.Large-size asphalt macadam base is a flexible structure, with a highly flexibleand deformation capacity can solve the problem of crack resistance of the pavementstructure. When the semi-rigid base emerge cracks, using large size asphalt mixtureto replace the cracking of cement stabilized crushed stone on the base, setting theasphalt treated Interlayer of the large particle size between semi-rigid base withcracks and the asphalt surface layer. Maintenance road is the grassroots with thecracks in the structure. With the growth of the age of the road, road base repairgradually increased, large size asphalt mixture will become increasingly large shareof primary disease maintenance. Application of large-size asphalt macadamprovides a new direction for the maintenance of the primary disease.The content of this paper includes four aspects:1) Asphalt pavement cracksurveys and genetic analysis. Investigation crack distribution characteristics,analysis of the causes of cracks and their impact on the mechanical state of the road;2) Large-size asphalt macadam grading design. The proposed aggregate gradationdesign method based on the shear resistance, shear strength and porosity asindicators to determine the stability of the skeleton structure and the amount of fineaggregate.3) Large-size asphalt macadam base research on performance test.Research gradation and binder type on the performance of large size asphaltmixture shear and flexural performance. Using uniaxial penetration test evaluatethe shear performance, trabecular low temperature test assess the flexure-tensionresistant performance.4) Combined with the test results of large-size asphaltmacadam probe the crack resistance evaluation index. Consider the shear strengthand porosity indicators to determine the aggregate gradation, evaluate the crackresistance of different binder types of critical strain energy density; The applicationpenetration shear strength and critical strain energy density index comprehensive evaluation crack resistance of the material; to reveal aggregate gradation, bindertype on the crack resistance of the large-size asphalt macadam investigated. Theresearch results can be used for the large-size asphalt macadam base designguidance for primary repair and construction, improve maintenance of the life ofthe asphalt pavement and road performance, and ultimately improve the economicand social benefits of highway maintenance. |
