Developing of a SBS polymer modified bitumen to avoid low temperature cracks in the asphalt facing of a reservoir in a harsh climate region

A SBS polymer modified bitumen (SBS-PMB) was developed to avoid low temperature cracks in the asphalt facing of the upper reservoir of Huhhot project, where the design minimum ambient temperature is −41.8 degree centigrade, the lowest one in the similar completed project in the world. By the time of construction commencement of Huhhot project, the SBS-PMB which can keep the impervious asphalt facing from cracking under such a low temperature was not available in the Chinese market, and had to be developed. With reference to the experiences from research and constructed project before, the fracture temperature (EPIS-PRC DL/T 5362-2006) was chosen to be the control parameter to judge the suitability of candidate bitumen, and was determined by the designer to be lower than −43 degree centigrade for Huhhot project. In the developing process of SBS-PMB, it was shown that the SBS modifier has to be used together with a suitable stabilizer and a compatilizer, in order to improve the stability and the compatibility of SBS polymer to the base bitumen. The feasibility of the developed HMB 5 was verified by the test of fracture temperature of asphalt concrete, as well as the trial slope paving test on the project site, and the impervious asphalt concrete facing on a slope of 1:1.75 can be compacted by paver and roller to a dense state with its void rate being lower than 3%. Furthermore, the knowledge of the correlations established between the fracture temperature of asphalt concrete and the low temperature ductility as well as the brittle point of bitumen can be used in further project.