Experimental Performance Evaluation of Microsurfacing Surface Treatment Containing Polypropylene Fibers

Appreciating the crucial importance of roads in keeping different areas connected to one another, road maintenance and repair represent a vital role of any road transportation management. Microsurfacing is an important preventive method for paved road maintenance. The present research is aimed at investigating the effect of adding polypropylene fibers into microsurfacing mix on its performance. For this purpose, performance evaluation of the microsurfacing mix was conducted by preparing five different mixes containing polypropylene fibers at different dosages, namely 0, 0.05, 0.10, 0.15, and 0.20% by weight to the weight of total aggregate. Analyses were performed by doing wet cohesion test, loaded wheel test, and wet track abrasion test according to ASTM D6372. Results showed that the polypropylene fiber-reinforced mixes exhibited improved microsurfacing performance. Among other mixes, the one containing the fibers at 0.10% showed 20.6 and 21.1% higher bitumen cohesion in the 30- and 60-min cohesion tests, respectively. Also using this mix, vertical and lateral displacements could be reduced by 38.2 and 28.9%, respectively, resistance to abrasion improved by 35.6%, and bleeding decreased by 25.4%. Compared to the control specimen, the mix containing polypropylene fibers at 0.10% exhibited 1.6% higher bitumen emulsion, providing for achieving the desired cohesion within a predefined period of time. The other results showed that excessive incorporation of the polypropylene fibers into the microsurfacing mix would inhibit optimal dispersion of the fibers across the mix, leading to accumulation of the fibers in the form of nodules and hence deteriorating the mix performance.