Analysis On Mechanical Characteristics Of Asphalt Pavement Structure With Rockfill Subgrade And Study On The Composition Design Of ATB-30

With the rapid development of highway construction,mountainous expressway has been more and more constucted.For mountain area lack of good packaging materials,and we want to make full use of spoil made by cutting and tunnel excavation,so rockfill subgrade which can make full use of local materials and reduce the cost of projects has become a common form in mountainous highway subgrade,and this article puts forward the optimization of expressway pavement structure under rockfill subgrade condition,and using thickness of asphalt treated mixtures ATB-30 as flexible base to overcome the semi-rigid bituminous pavement easily have early disease,also this paper made a further research on asphalt treated base.This article study the mechanical characteristics of the three kinds of pavement structure under rockfill subgrade condition,and mainly analyze the shear stress and tensile stress changes in pavement structure and the result show that,due to rockfill subgrade have higher modulus,so the shearing stress of the pavement structure decreases,but for the flexible base is used,the tensile stress at the bottom is higher than the semi-rigid base structure,so we must increase the thickness of the flexible base ATB-30 to reduce the tensile stress at the bottom,and according to the calculation and analysis,this article recommen a pavement structure with the flexible Base under rockfill subgrade condition.Also this text made a further research on ATB-30.First,using different kinds of gradation design method to design five kinds of gradation;Then,comparing the methods of specimen molding,this article finally choose SGC method to mold specimens and find out the optimal asphalt content of different aggregate gradations.Base on ATB-30 have larger thickness in pavement structure and Through the information of gyratory compaction densification curve of SGC,K1,K2,CEI and TDI,these four parameters are chosen to analyze and study the compaction characteristics of ATB-30,by comparing,4# gradation is chosen to process some indoor tests,high temperature stability,crack resistance in low temperature and water stability of ATB-30 are studied.The results show that the choosed gradation can meet the requirements of the pavement performance.