| Summary: | This study presents the utilization of polyethylene (PE), a waste products as a modifier for road aggregates. Polyethylene has been used widely in packaging, pipes, garbage bag and bottles. Waste material especially plastics waste is a serious environmental issue. There is a high demand of plastics in the industries as a packaging and disposable consumer items due to its inexpensive, lightweight and durable properties. Plastics waste is a non-biodegradable material and hard to be disposed, recycling or turning it into a useful material is the only effective means. The PE used in this product is from plastic scraps that has been granulated to form into granules. The purpose of this study is to evaluate the properties of PE modified bituminous mixture in comparison to conventional bituminous mixture. Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE) were mix together as a modifier, added to the aggregate creating a thin film of coating on the aggregate surface. Bitumen content of 4.0, 4.5, 5.0, 5.5 and 6.0% were used for asphaltic concrete wearing (ACW 14) to determine the optimum bitumen content (OBC). ACW14 with maximum nominal aggregate size of 14 mm was designed using AC14 gradation limit where the percentage passing accordance with Arahan Teknik (Jalan) 5/85. Total of 15 control samples (0% additive) were prepared based on the mix design, where 3 samples for each of bitumen content in order to obtain average value. Based on preliminary laboratory works, a maximum of 2.0% of polyethylene by weight of aggregate can be added in bituminous mixture without compromising the Marshall properties. 15 samples for modified sample also were prepared. All samples approximately 1200 grams in weight were compacted with 75 blows on each side. Each of compacted bituminous samples were tested for Marshall stability and flow as per ASTM D 1559. From the result of 2% HDPE-LDPE blend, the OBC required by bituminous mixture is 4.97% compared to 5.19% OBC for control mix. The reduction is 4.2%. In large scale production, this will reduce the usage of raw material as well as to reduce the cost of road construction. By coating the aggregate with PE, it improves the strength and reduce water absorption. In long term, this will help to reduce stripping problem.
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