Use of Waste Plastic and Waste Rubber in Aggregate and Bitumen for Road Materials
Many roads agencies have been experiencing problem of premature failure of pavements like potholes, roughness, cracks and etc. which leads to poor performance of roads and its life. On the other hand, plastics, rubbers, etc. are increasing day by day. Waste like plastic bottles, polymers, cups, waste tyre's can be re-used by powdering or blending it with crusher's and can be coated over aggregate and bitumen by any heating process. In this study we have used polymer and crumbed rubber as a binder with respect to aggregate and bitumen. In bituminous roads, we use materials like aggregate (of various sizes), grit and bitumen. The various tests are conducted during this study on aggregates such as crushing value, impact value, abrasion value, and specific gravity and also on bitumen penetration value, ductility, softening point. The results are discussed in this paper.
Experimental investigation of waste plastic bottles as partial replacement of aggregates in flexible pavements
Global plastic pollution reported that; 1 million plastic bottles bought every minute, 100,000 marine animals killed by plastic each year, 500 years to degrade in the environment, 90% of bottled water contain plastic particles. Ethiopia is facing rapid urbanization and industrialization leading to the packing of different industrial products with plastic bottles which finally becomes waste and on the other side, pavements are behaving different structural failures and surface defects before the end of the construction period and service year. In order to minimize the above serious problems, this research was initiated to do the experimental investigation of a waste plastic bottle as partial replacement of aggregate in the bituminous concrete mix through a dry process to enhance the desired performance of bitumen concrete mix and to reduce plastic bottles disposal problem. Before applying PET bottles as additives, optimum bitumen content was determined for conventional bitumen concrete mix which is selected as 5.33%; upon which the effect of PET bottles experimented. Waste plastic bottles are collected and cut into pieces using scissors. Then it was melted in an oven at 180⁰c for 30 minutes. Then after cooling down, it was pulverized. Finally weighing the required amount of pulverized plastic and replacing the aggregate by 0%, 4%, 6%, 8% and 10% by weight of aggregate, the marshal test was held and volumetric properties on each specimen were computed. Based on the laboratory result, the optimum plastic content was selected at the specimens that have high stability; high bulk density and minimum air void values are 20.66 KN, 2.59gm/cm3 and 3.25% respectively. The optimum plastic content is selected at 4% of plastic bottle by weight of aggregate. Lastly, this study concluded that partial replacement of aggregate by the waste plastic bottle can increase the overall performance of the bitumen concrete mix. Finally, this study recommends it is better to apply this new construction technology on the ground and to adopt it. It is better to know the cost benefit analysis on partial replacement of aggregate by waste plastic bottles in flexible pavements.
Improvement of water-stability of clay aggregates admixed with aqueous polymer soil stabilizers
Abstract Aqueous soil stabilizers improve soil properties. Water-stability of soil aggregates was determined using two different soil stabilizers: S-type and E-type. Various concentrations of the two soil stabilizers were tested in soil aggregates that were bigger than 5 mm but smaller than 10 mm. Testing the aggregates using the static water-measure method showed that the water-stability index, K , increased with the concentrations of soil stabilizers. S-type soil stabilizer in concentrations ranging between 20% and 40% resulted in K -values between 64.0% and 83.8%, and E-type polymer emulsions in concentrations between 3% and 7% resulted in K -values between 90.1% and 99.7% respectively. The soil aggregates admixed with water resulted in a K -value of 11.5%, which was tested as a control. Two aggregate collapse models were found and discussed based on the collapse characteristics of the modified aggregates: S-type soil stabilizer in low concentrations follows a gradual collapse pattern, while S-type stabilizer in high concentrations and E-type stabilizer in low concentrations follow an explosive collapse pattern. These patterns depend on the formation of a membrane structure on the surface of the aggregates through physicochemical bonding. By identifying the mechanisms of the membrane structure and calculating the K -values, significant information on the improvement of soil properties can be determined.