Laboratory Investigation of Microsurfacing Asphalt Modified with Nanosilica and Nanoclay Combined with Polyethylene Fibers

摘要

Microsurfacing asphalt is a thin surface treatment comprising asphalt emulsion, filler, and crushed stone materials that can be defined as a protective asphalt that has low thickness and is adaptable to the environment. In this study, the mix design was specified in terms of the optimal percentage of additives to asphalt emulsion; the additives contained 4 wt. % nanosilica and 3 wt. % nanoclay in addition to 0.4 wt. % polyethylene fibers that can be defined as a kind of flexible fiber-reinforced microsurfacing. The results of the abrasion test indicate that an increase in the resistance to long-term moisture sensitivity in fiber-reinforced microsurfacing occurs when resistance against abrasion in this sample is increased 30 % and the contents of nanoclay and fiber are in an optimal combination. The results of the sand adhesion test demonstrate that an increase in the amount of nanosilica is far more effective than an increase in nanoclay and fiber. Also, a comparison of the results of the cohesion and loaded wheel tests reveals that the specimen with the greatest possible cohesion between its components still has a low vertical displacement; thus, it is recommended as the best combination for producing and manufacturing highly flexible fiber-reinforced microsurfacing. This indicates that nanosilica and fiber effectively modify surfaces. Additionally, a 46 % improvement in rutting resistance and a 27 % increase in the flexural tensile strain was obtained in the fiber-reinforced microsurfacing.