Design And Performance Of Cold Recycled Mixture Using Emulsified Asphalt

Our country economy prosperity promotes the development of transportation enterprise. To the end of 2006, the total road course of our country has achieved 3,480,000 kilometers, in which the highway is 45,400 kilometers, which built in the 1990s has already entered the stage of heavy and medium maintenance. A massive of material, abandoned in the bitumen pavement maintenance, rehabilitation and reconstruction, is reused through recycling, which has the strategic significant action in the present highway construction.At present, it does not have the uniform standard to the cold recycled asphalt mixture design method and its performance in domestic and foreign. Specially, the research on it is few in domestic. Through lots of laboratory tests, this article systematically introduces and discusses the design method for cold recycled asphalt mixture using emulsified asphalt and its performance, meanwhile contrasts with the ordinary hot mix asphalt technical specification.The test results show that the specimen is completely dry after curing at 60°C for 3 days, which has represented the ideal condition of cold recycled asphalt mixture. The optimum water content can be determined according to the principle of maximum dry weight density. The optimum binder to aggregate ratio is basic consistent, determined by by means of either Marshall or Indirect Tensile test at 25°C in the dry and wet condtions, which increases in nearly linear function with RAP content increasing. As the important parameters of pavement structural design, resilient modulus at 20oC and 15oC and the indirect tensile strength at 15oC all meet the specifications of ordinary hot mix asphalt. The dynamic stability at 40oC only has the relative comparison significance, changing from 19000cycles/mm to 3600cycles/mm. TSR all being about 60% and the failure strain at -10oC changing from 1500μεto 2000μεdon't meet the specifications of ordinary hot mix asphalt. The volume of air voids of mixtures is high, but the permeable coefficient is small, which still meet the specifications of ordinary hot mix asphalt. The indirect tensile strength decreases a lot after adding Lanting recycling agent, which has not achieved the anticipated goal.