Study on performance and microstructure of SBS modified asphalt AH 70 before and after emulsification

Key words:  SBS modified asphalt  emulsification  macroscopic properties  microstructure  thermal stability

Abstract:

The styrene butadiene block copolymer (SBS) modified asphalt emulsion was prepared by a modification emulsification process. The performance of emulsion residue and modified asphalt was analyzed. The microstructure and thermal stability of SBS modified asphalt before and after emulsification were evaluated by means of fluorescence microscope, FT IR, ¹H NMR and DSC. The results show that compared with modified asphalt, softening point, 5 ℃ ductility and elastic recovery of emulsion residue decrease and the difference of top and bottom softening point on separation test becomes large. However, those properties were still improved compared with base asphalt and conformed to I D standard. SBS modified asphalt exhibits uniform three dimensional network structure. After emulsification, the cross linked structure between asphalt and SBS molecules remains unchanged, with a small amount of large SBS particles separating from modified asphalt, minimally aging of asphalt and slight reduction on the thermal stability of modified asphalt.