The research for SBS and SBR compound modified asphalts with polyphosphoric acid and sulfur

• PPA is negative for the stability of SBS-modified asphalt.
• PPA and sulfur are complementary in the further modification of PMAs.
• PPA and sulfur have opposite effects on the morphology of polymer in asphalt.

Styrene-butadiene-styrene block copolymer (SBS)-and styrene-butadiene rubber (SBR)-compound modified asphalts with good storage stability and high- or low-temperature properties before and after short- and long-term ageing are prepared by the addition of polyphosphoric acid or sulfur selectively. The effect of PPA and sulfur on the storage stability, the physical and rheological properties of SBS- and SBR-modified asphalts before and after ageing is studied. To improve the storage stability, high- or low-temperature properties of SBS- and SBR-modified asphalts before and after ageing, the SBR-modified asphalt should be modified further only by the addition of PPA, the linelike SBS-modified asphalt should be improved by the addition of PPA and sulfur, the starlike SBS-modified asphalt should be improved only by the addition of sulfur. The modification mechanism of PPA and sulfur in the preparation of those polymer modified asphalts (PMAs) is studied further.