ABSTRACT
Polyphosphoric Acid (PPA) is a well-known bitumen modifier which is widely used in the US and Europe as a neat modifier and in combination with polymers. When PPA is used for modification it increases high-temperature Performance Grade (PG) rating of the bitumen while maintaining the low-temperature properties. Significant improvements in rutting and the water-sensitivity of bituminous mixes are also obtained. When combined with SBS-type polymer PPA has been found to replace SBS in polymer-modified bitumen (PmB) while maintaining specification compliance. The present work shows the development of a prototype PmB using binders representative of those found in the market in China. It was found that up to 40% of the SBS can be successfully replaced while still maintaining the specifications. Neat and modified binders were graded using AASHTO M 320 (US specifications) and AH-70 (Chinese specifications); in particular, we focused on elastomeric properties such as elastic recovery, ductility, MSCR% recovery and non-recoverable compliance
