LAUSR

Although microstructure is closely related to performance and is even considered decisively influential, this paper addresses the poorly understood morphology characteristics of styrene-butadiene-styrene (SBS). Eighteen groups of polymer-modified asphalt (PMA) were prepared with three binder sources, four SBS polymers and five modifier contents. Fluorescence microscope images and Fourier transform infrared (FTIR) spectroscopy were used to study the morphology characteristic and compositions. Fractal dimensions, average expansion diameter and FTIR peak area were proposed as the quantification parameters to describe the intricate morphology characteristics and functional groups. Expansion multiples of each polymer were deduced based on the principle of calculus variation. Furthermore, ANOVA was used to analyse the stability of the proposed quantification method. Results show that fractal dimensions can be used to characterise the microstructures and polymer swelling status of modified asphalt. For most SBS polymers in this study, the polymers swelled 6.12–8.38 times larger than their original particle size. The results indicated the potential for these quantification parameters to evaluate the PMA and its application for quality assurance.