Testing and Evaluating the Effect of Adding Fibers and Nanomaterials on Improving the Performance Properties of Thin Surface Asphalt

Abstract Thin surface treatments are used to improve the functional condition but not the structural condition of a roadway. In this study of superior adhesion, flexibility, and durability values, an optimum combination of quick emulsions of cationic modified with styrene butadiene rubber polymer and hybrid nanomaterial (by 4 wt. % nanosilica and 3 wt. % nanoclay) additives and asphalt emulsion, together with consuming 0.4 wt.% polyethylene fibers that can be defined as a reinforced thin surface treatment, or fiber-reinforced microsurfacing, was used. An appropriate mix design was selected according to the results of a cohesion test, wet track test, and load wheel test. It was found that the effect of nanomaterials on the increase of the stability of the mixture and accelerating setting for a quick crossing of traffic flow was achieved by far more than adding residual asphalt and fiber to the mixture. Since cationic emulsifiers act as antistripping agents after breaking of the emulsion, nanosilica also causes an 8 % increase in adhesive asphalt emulsions. Also, the results show that nanosilica caused a 5 % increase in the cohesion of the asphalt emulsion. The nanoclay, on the other hand, was found to cause a 12 % increase in the resistance to surface abrasion. However, the application of the nanosilica and fiber causes acceleration of the emulsion break. Furthermore, considering the role of fibers in crack prevention, the results obtained from the low-temperature flexural creep test show an increase in the flexural tensile strength value by 17 %, which is used to evaluate the cracking resistance, and a 27 % reduction in the value of displacements, as well as resistance to rutting.