Improving the high-temperature performance of cold recycled mixtures by polymer-modified asphalt emulsion

Abstract

With the development of modified emulsified asphalt, cold recycling technique has the potential to be used in pavement layers closer to surface. Three modified emulsified asphalt binders were carefully prepared by adding Styrene–butadiene rubber (SBR) latex, styrene-ethylene–butylene-styrene (SEBS) copolymer and chloroprene rubber (CR) latex, respectively. In order to characterise how the properties of asphalt binder related to the rutting of cold recycling mix. The high temperature Dynamic Shear Rheometer (DSR) and Multiple Stress Creep Recovery (MSCR) tests were conducted under varying test temperatures ranging from 46 to 76 °C. An advanced cyclic creep test was conducted to study the rutting resistance of the full-depth pavement structures with cold recycling mix. According to the test results, the high-temperature performance were improved significantly by adding the polymer modifiers, and adding CR latex seems to be a more effective way to improve the rutting resistance of emulsified asphalt. Results from MSCR test under temperatures no less than 64 °C shows a better correlation with test results from the advanced cyclic creep test than the G*/sin δ from high temperature DSR test. Thus, by carefully choosing the test temperature and stress, the MSCR test shows promise to be a surrogate to the existing DSR test.