Damaging effect of fine grinding treatment on the microstructure of polyurea elastomer modifier used in asphalt binder

Abstract

The excellent elasticity and strength of polyurea elastomer could provide good potential in asphalt modification. In this paper, PUA materials were prepared by spraying and crushing technology. Using liquid nitrogen, PUA was ground into powders of different particle sizes. The size composition and characteristics of PUA powder were analyzed using laser particle size analyzer. The functional microstructures were identified through laser confocal scanning microscopy. The damaging effect of grinding on functional microstructures was investigated. The impact of PUA on the rheological property of asphalt was determined. The results showed that the size distribution of PUA powders presents the normal distribution characteristic, and the size distribution of 0.3 mm, 0.15 mm, and 0.075 mm PUA powders have intersection. The spherical microstructure distributed independently in PUA particle and some spherical microstructure distributed in the triangular shape. The width/length ratio of characteristic microstructure in 0.15 mm and 0.075 mm PUA powder were increased, which supposed that the spherical microstructure had been damaged by grinding effect. PUA could reduce the cumulative deformation of asphalt when suffering from repeated loads.