Abstract:
The production and use of plastic bottles is increasing tremendously with passing time. These plastic bottles become a problem when they are disposed off as they are non-biodegradable. This means that the waste plastic, when dumped, does not decompose naturally and stays in the environment affecting the ecological system. Burning of this waste, too, harms the environment as it releases harmful dioxins which are hazardous to human health. The emission of CO2 is a major concern for environmentalists and world community as it is a primary greenhouse gas. Pakistan, with its high population and no proper recycling mechanism, faces this problem of plastic bottle littering. One of the solutions to the above mentioned problem is to use waste plastic bottles as a modifier in flexible pavements. Waste plastic bottles are shredded into smaller size and wet or dry mixing with aggregate bitumen blend can be performed. This study focuses on the use of waste plastic as a modifier to enhance the individual properties of aggregate and bitumen and the strength and durability of bituminous mixture. Moreover, this waste plastic when effectively utilized will reduce the impact on the environment. Aggregate was coated with shredded waste plastic and different tests were performed. Results showed a decrease in Impact Value, Crushing Value and Abrasion Value. Aggregate Impact Value decreased from 20.95% to 11.91%, Crushing Value reduced from 21.34% to 14.14% and Los Angeles Abrasion Value dropped from 20.16% to 10.84%. Marshall Results at Optimum Bitumen Content (OBC) and Optimum Plastic Content (OPC) supported the use of plastic as Stability Value increased by 27.02% due to better adhesion provided by plastic between aggregate and bitumen and flow value also increased. The value of Air Voids came out to be 3.84% and VMA (Voids in Mineral Aggregate) and VFA (Voids Filled with Asphalt) had a value of 14.3% and 68.6% respectively, showing that it adhered to the specifications provided by ASTM.
