Study On Lime-fly Ash Macadam Semi-rigid Base Reused In Rigid Base

Semi-rigid pavement structure is the main type of pavement structure in China. Because of heavy traffic and many other reasons, the early damage of semi-rigid pavement structure is seriously destroyed. Moreover, the early constructed freeway is going into the overhaul period one after another. The milled semi-rigid base material is enormously waste,and results in series of environmental problems. Considering the serious waste of milled semi-rigid base in freeway overhaul, a technique on reclaimed lime-fly ash macadam used in rigid base was studied.The reuse of semi-rigid base material domestically and abroad is primarily in the company of asphalt surface-course milled and makes cool recycling.This thesis combines with the major repair works in the section of Dezhou between JingFu expressway, discusses the feasibility of reclaimed lime-fly ash macadam reused in rigid base and asphalt pavement.According to laboratory experiment,the particle shape,apparent density,void fraction,characteristic of water-intake and crush value of the recycled aggregate are studied, then the analysis in contrast with the natural aggregates is made,and the basic performance parameter of the recycled aggregate is obtained.The thesis discusses the mix ratio design of rigid base used the recycled aggregate, according to the laboratory experiment and practical road performance, ascertains the best mix ratio which accords with the pavement design. As well, according to the laboratory experiment and theoretical research, the performance of the recycled aggregate rigid base(fatigue characteristic,contractibility,durability and so on ) is analysed, based on the laboratory experiment which indicates the reuse technique of the lime-fly ash macadamix semi-rigid base is completely able to fulfil the road performance.Next,the test results are used in the testing segment, on the basis of road construction of the testing segment,we could draw the conclusion that the recycled aggregate rigid base has the good road performance.In the end , the economic feasibility analysis of the recycled aggregate rigid base is made,which is in favour of the use of the lime-fly ash macadamix recycled aggregate and the recycled aggregate rigid base, furthermore, some suggestions are raised for the future research.