Quantifying the effect of modified mixture volumetrics and compaction effort on skid resistance of asphalt pavements

Abstract

ABSTRACT This paper aims to quantify the effect of modified mixture volumetrics and compaction effort on surface characteristics of asphalt pavements. Specimens were prepared using PG 64-10 asphalt binder mixed with crushed limestone aggregate. Three types of asphalt modifiers were added; Crumb Tire Rubber (CTR), Microcrystalline Synthetic Wax (MSW) and Nano Silica (NS). In addition, specimens were adjusted at 4% air void and were compacted at Design Number of Gyrations (Ndes) = 119 and 82 to simulate high and low levels of traffic, respectively. Research findings revealed that Air Voids Volume (Va) and Effective Binder Volume (Vbe) exert a significant effect on the surface frictional properties. Additionally, the ratio of Va to Vbe, expressed as Pv, was also investigated to study the combined effect of Va and Vbe on surface friction results. It was concluded that Pv has a considerable role in the evaluation process. It was also shown that increasing the level of compaction would result in a positive effect on British Pendulum Number (BPN) measurements and the opposite is true in terms of macrotexture measurements. Furthermore, CTR-modified mixtures exhibited the highest values of friction and macrotexture followed by NS-modified mixtures. MSW-modified and unmodified mixtures exhibited the least fractional characteristics.