Study On Characteristics Of Grade Macadam

Although semi-rigid base has been applied broadly, for the increasement of traffic and the development of heavy traffic, it has two disadvantages: one is the heavy crosswise shrink crack; the other is the bad structure draining condition. Many projects have proved that these two disadvantages lead to early damage of bituminous pavement. This article bring forward using graded aggregate as the middle layer of bituminous layer and semi-rigid base to solve the two disadvantages. We choose it because graded aggregate can absorb and weaken the stress and strain of crack tip of semi-rigid base to prevent the reflection cracks from occurring and it has good drain performance.Graded aggregate soft base comes from rolling on the incompact material with low felt, so the use of graded aggregate has the disadvantages of large permanent deformation and low modulus of resilient. How to solve the disadvantages of graded aggregate through the design of grading and sound moulding technics is the stress of this article. We use vibrant moulding technics to meet the requirement that moulding reflects modern machine. Besides using classic CBR experimentation as a appraise method, we introduce repeated load MTS experimentation, it can separate elasticity and permanent deformation, it can let us analyse the deformation characteristic of graded aggregate. These two appraise methods supplement each other, analyse questions from different point of view.Chapter five is concluding and suggestion. Not only put forward the production of this study, but also bring forward the studying content and direction which we would continue to do.