Low temperature adhesion performance of polymer modified Bitumen emulsion in chip seals using different SBR latexes
ABSTRACT Due to increasing use of styrene butadiene rubber (SBR) latex in the preparation of polymer modified bitumen emulsions (PMBE) to improve bitumen aggregate adhesion of chip seal surface treatments and lack of scientific data on the effect of SBR micro structure on the performance of the resulting treatment at low temperatures, the Vialit test was conducted. The conventional tests showed that addition of SBR and X SBR to PMBE reduces bituminous residue (BR) penetration and enhances its penetration index (PI) and softening point. Also, addition of linear SBR latex to bitumen results in an increase in BR ductility and recovery at low temperatures. Meanwhile, addition of the branched carboxylated styrene butadiene rubber (X SBR) latex reduces ductility of the corresponding BR. The effect of the performance of bitumen emulsions on aggregate bitumen adhesion in chip seals was investigated using Vialit test. It was found that an increase in SBR latex content in bitumen emulsion leads to an increased aggregate retention; this effect is more pronounced at low temperatures. Comparatively, the addition of X SBR latex results in a lower bitumen aggregate adhesion at low temperatures.