Study On Long-mid Term Performance Of Cold Recycling Mixture With Foamed Asphalt And Emulsified Asphalt

Highway maintenance department belonged to Ministry of Transport of the People’s Republic of China had issued the guidelines for development of the twelfth-five year plan. It required that the cyclic utilization rate of waste pavement materials should reach 40% in the highway maintenance process, which includes that cyclic utilization rate of the pavement materials of the national and provincial arterial highway should reach 70%, and the cyclic utilization rate of the pavement materials of the freeway should reach 100%. The cold recycling technology is the technology which can reuse waste asphalt mixture, raise resource utilization ratio, and the quality and service life of the asphalt pavement, accords with the strategic policy of developing recycle economy and realizing sustainable development in our country. So the study of the cold recycling technology has important practical significance.The accelerated curing protocol is the important step in the cold recycling mixture with foamed asphalt. This paper studies the variation of the moisture content and resilience modulus of the cold recycling mixture with foamed asphalt. The results of the study show that the evolution of the moisture content and resilience modulus has two stages that includes the change stage and stable stage with the curing time. The strength of the cold recycling mixture in condition with sealed specimen, forms the faster than unsealed specimen. In condition of 40℃, the strength of the cold recycling mixture forms higher than the strength in condition of 30℃.This paper recommends mix design process based on foreign and domestic experience. This paper puts forward the mixing water content of the foamed asphalt mixture is 65 to 75 percent of the optimum moisture content with heavy compaction test and the emulsified asphalt mixture adopts the method of the optimum fluid content determination with heavy compaction test to determine the mixing water content. In addition, this paper recommends ITS and residual ITS as the design index of the first stage of mix design, ITS and UCS as the design index of the second stage of mix design, the shear parameters as the third validation index.This paper uses the triaxial shear test to study of the influence of different material compositions on dynamic shear resistance performance of foamed asphalt and emulsified asphalt recycling mixture at the temperature 25℃. It was indicated that the internal friction angle was decreased, but the cohesion is increased at first then decreased with the increasing of foamed asphalt and emulsified asphalt content. The increase of cement and RAP content is beneficial to the increase of shear index for foamed asphalt and emulsified asphalt recycling mixture.Through to investigate traffic, design and construction material of XiYan highway, XiHu highway and TongHuang highway, this paper studies the later performance of foamed asphalt and emulsified asphalt recycling pavement.At last, the paper recommends the detection method of cement content with EDTA titration, and the detection method of foamed asphalt and emulsified asphalt content with two burning method.