Study On Lime Flyash Stabilization Of Cold Reclaimed Asphalt Pavement Mixture For Road Bases And Subbases

While highway constuction is booming, highways built in early years have entered the maintaining period, and the quantity of asphalt roads that need to be maintained is increasing annually. As a result, each year a great quantity of old asphalt pavement materials will be produced, which can be recycled instead of being discarded, neglecting resource waste and envirionment pollution. Therefore, it is urgent to study the recycling technology of asphalt pavement. Cold recycling technology is one of it, which has been very mature abroad, but is young in our country. This paper primary studies the technology of lime flyash-stabilized cold reclaimed asphalt pavement mixture for bases and subbases.Lime flyash-stabilized cold reclaimed asphalt pavement mixture for road bases and subbases belong to cold recycling technology of asphalt pavement. The principle is the reclaimed material (including old pitch mixture and some old lime clay) is reused as subject, and is stabilized by lime flyash, which, through mixing, compaction and curing, forms bases or subbases, similar to other semi-rigid bases stabilized by lime flyash.This paper carries on systematic indoor experimental study. Firstly, the physical and mechnical properties of the raw materials are studied. Secondly, unconfined compressive strength, cleavage strength and compression modulus of cold recycling materials are researched by orthogonal method. The change law of each index related to ratio of old lime clay to old pitch mixture, lime flyash content, and curing age is summed up. The relation between compressive strength and compression modulus is estabalished. Thirdly, the temperature shrinkage, dry shrinkage, water stability and frost stability are tested and analyzed. The grey relation entropy method is applied to analysis of influence factors of temperature shrinkage and dry shrinkage, and measures to reduce shrinkage are put forward as well.Finally, the structural design method of cold recycling is introduced in this paper. To combine with the test results, the paper recommends a series of design parameters that may be helpful for design, construction and further study work. In addition, Engineering economy study is carried our, combined with actual project, the functional performance of cold recycling structure is evaluated. Study results indicate that the technology of lime flyash-stabilized cold reclaimed asphalt pavement mixture for bases and subbases.is a favorable maintainance and reconstruction method for highways, and it will bring inestimable economic , social and environmental benefit.