Air Void Characterization in Sand-Sulfur-Bitumen Mixes

Abstract

This paper represents an attempt to study the internal structure of sand-sulfur-bitumen (SSB) mixes with the help of effective and quick three-dimensional (3D), high-resolution technology such as X-ray micro-computed tomography coupled with digital image processing tools. Various air void parameters, such as air void content, connected air void content, size and shape of air void, and tortuosity of compacted specimens, were determined and compared with those of a conventional dense graded bituminous mixture. Further, a statistical approach was used to fit the distribution of air void size in SSB mixes based on a lognormal function. The associated scale and location parameters of the lognormal function were used to evaluate the influence of various factors such as type of filler, use of crusher dust, and variation in bitumen content on the distribution of air void size. A substantial improvement in the air void characteristics and tortuosity was observed with the addition of fillers and crusher dust, although the effects of filler type were not significant.