Study On The Road Performance Of Waste Cement Concrete Recycled Aggregate

Since China's first highway opened to traffic, the cement concrete pavement due to its advantages of high strength, high rigidity, good durability, has received more and more applications. However, under the effect of traffic load and natural environment, the emergence of a variety of diseases, and into the large or medium repair period,and it will produced lots of waste cement concrete piled up on both sides of the road occupation of land resources. How to deal whit the large number of waste concrete which were produced by road reconstruction has become a urgent problem of the highway management department. According to the research results of experts and scholars in recent years, after the waste cement concrete were crushed, used as the road base is a kind of solution.In this paper, we use the waste cement concrete which were produced form the Guangxi Liuzhou(Luzhai) to Nanning highway expansion project as raw material. Through crushing and a series of experiments to determine the recycled aggregates can meet the requirements of the specification of the aggregate, and get the following results :1?Sieving of the recycled aggregate which were crushed for the first time, results show that particle size of the the recycled aggregate meet the ?Technical Specification for Construction of Highway Roadbases?, crushing the recycled aggregate for the second time which size exceed 31.5mm, the aggregate size is fine, does not meet the requirements of the specification.2?Physical and mechanical properties of recycled aggregate, such as apparent density, water absorption, flat and elongated in coarse aggregate, crushing value and so on, the test results can meet the requirements of ?Technical Specifications for Construction of Highway Asphalt Pavement?, But compared with the natural aggregate,it still have a gap, especially the water absorption of recycled aggregate is about 6-7 times higher than the natural aggregate. So when it been used in engineering application, we should pay more attention on the water absorption of the recycled aggregate.3?The optimum water content and maximum dry density of cement stabilized recycled aggregate,which was mixed 3%, 5% and 7% cement,were determined by compaction test. And then make concrete specimen to test of cement stabilized material 7 days, 14 days, 28 days, 90 days unconfined compressive strength. Results show that the more cement, the higher compressive strength,and the best cement content is 55~6%, and the best curing period is 14 days.4?when the exposure time was increase,the dry shrinkage coefficient of the cement stabilized recycled aggregate was increase,too. In the first 30 days, the growth rate of cumulative water loss and dry shrinkage coefficient were fastest.After 30 days the growth rate was slow down. When the rate of cumulative water loss more than 3%, dry shrinkage coefficient was rapid growth. So according to the result of test suggest the best curing period of the cement stabilized recycled aggregate is 30 days...