Partial replacement of coarse aggregate by scrap rubber tire in concrete construction

Abstract

Concrete is one of the most widely used construction materials in the world. Cement and aggregate, which are the most important constituents used in concrete production, are the vital materials needed for the construction industry. This inevitably led to a continuous and increasing demand of natural materials used for their production. Parallel to the need for the utilization of the natural resources emerges a growing concern for protecting the environment and a need to preserve natural resources (such as aggregate) by using alternative materials which are recycled or waste materials. In this research, a study was carried out on the use of recycled rubber tires as a partial replacement for coarse aggregates in concrete construction using locally available waste tires. In the first part of this thesis, the background of the study and the extent of the problem were discussed. The research was carried out by conducting tests on the raw materials to determine their properties and suitability for the experiment. Concrete mix designs are prepared using the Indian standard method and a total of 9 mixes were prepared consisting of three concrete grades (M15, M25 and M30). The specimens were produced with percentage replacements of the coarse aggregate by 10%, and 25% of rubber aggregate. Moreover, a control mix with no replacement of the coarse aggregate was produced to make a comparative analysis. The prepared samples consist of concrete cubes, cylinders and beams. Laboratory tests were carried out on the prepared concrete samples. The lists of tests conducted are; slump, unit weight, compressive strength, splitting tensile strength, and flexural strength tests. The data collection was mainly based on the tests conducted on the prepared specimens in the laboratory. The test results were compared with the respective conventional concrete properties and show that there replacement should be limited to a specified amount and the application should be restricted to particular cases where the improved properties due to the rubber aggregates are desirable and when the corresponding demerits of the rubber aggregates don't affect the use of the structure.