Development of a GPC Chromatograms Decomposition Method for Identifying and Quantifying the Degradation of SBS Polymer Modified Bitumen

SBS polymer modified bitumen (SPMB) can notably improve the performance of asphalt pavement and is widely employed on the surface layer of pavements. However, SBS polymer is sensitive to ageing and its degradation evolution is difficult to be quantitatively characterized due to the overlapping of GPC chromatograms. In this research, a chromatogram decomposition method (CDM) is proposed based on a combination of experimental quantitative analysis and mathematical deconvolution methods, which target simultaneous identification and quantification of degraded SBS polymers in SPMB. According to the experimental and analysis results, the overlapped chromatograph peaks of 24 different SPMB binders (different SBS contents, base bitumen types and ageing levels) were successfully decomposed and the degraded SBS polymer was quantitively analyzed by the CDM method. Meanwhile, the CDM analysis parameters of SPMB binders demonstrated a good correlation with the rheological characterization results, indicating the validity of the proposed CDM method. These results revealed the degradation process of SBS polymer during the aging of SPMB, and also provide a promising analytical strategy for the polymer modified bitumen with overlapped GPC chromatograms.