Study On Compaction Characteristics For The Thick Asphalt Pavement

Expressway asphalt pavements expose series of problems early in their service life in our country ,such as rutting,water damage and cracks etc. The pavement destruction is serious. In this paper, the research and analysis of the design for structure and material of thick layer asphalt concrete pavement were made based on the design of pavement structure.Asphalt pavement is divided into two asphalt pavement structures which include normal thickness and thick layer. Elastic layer theory calculation program-Bisar was used to analyze the change of maximum shear stress and distribution location and the effect of the stability of anti-rutting on the whole thickness on the asphalt pavement surface fixed and differ layered. It also analyzed the change of the peak tensile stress and distribution location of the inner of asphalt pavement surface for the effect of crack property of anti-fatigue. The result showed that the stability of anti-rutting and crack property of anti-fatigue was enhanced by using thickness asphalt pavement structure.Three factors (CA ratio,asphalt content, gyratory compaction times)were analyzed by range and variance analysis which ascertain the effect degree of every factor to the asphalt mixture compactness using Superpave Gyratory Compactor molding method and orthogonal experiment design. Compaction characteristics of asphalt mixture could be evaluated with densification curves of asphalt mixture. The difficult degree of compaction in construction stage and compacting in using stage for asphalt mixture were evaluated by using four parameters (K1,K2, CEI, TDI).The optimal gradation of thick layer asphalt concrete AC-25 could be recommended. Different asphalt mixture gradations were selected to do rutting comparison test. The analysis result of densification curves was verified. And the chosen asphalt mixture gradations were used to do water stability test.