Volume 38, Issue 5 (September 2010)
Evaluation of Reclaimed Polyethylene-Modified Asphalt Pavements
Every year several million tons of low-density polyethylene (PE) carry bags are produced as waste in India. PE is not readily biodegradable and will persist in the environment in a more or less unchanged state for a considerable period of time. Also environmental problems are created due to dumping and also due to limited alternatives for recycling. Utilization of reclaimed PE is of great significance to developed/developing countries particularly for reduction in environmental pollution created due to dumping of PE bags. Since highways require huge amounts of construction materials, incorporation of only a small portion of recycled material will dispose of large quantity of PE bags. In the year 2002, conventional hot mix asphalt (HMA) (control) and PE-modified HMA (PEHMA) test sections were constructed along Outer Ring Road connecting National Highway-4 and Bangalore City. The performances of the control HMA and the PEHMA mixtures were evaluated periodically over a period of 5 years. The control HMA and PEHMA were subjected to a laboratory testing program that included tests to evaluate creep, indirect tensile strength, tensile strength ratio, resilient modulus (MR), gyratory properties, voids in total mixture, and bulk densities. Test results indicated that the PEHMA mixtures had lower moisture susceptibility, higher tensile strength, and resilient modulus. The gyratory properties and creep tests indicate that the PEHMA mixtures are more resistant to rutting. In-place performance was evaluated by pavement deflection and unevenness measurement for 5 years of the pavement’s life. Field performance results indicated that wheel path cracking was observed on the control section and no cracks were observed on the PEHMA test section.