ABSTRACT
Rubberized concrete is developed by partially substituting traditional concrete aggregates with shredded rubber sourced from recycled tires. The primary goal of this research was to explore the feasibility of using shredded rubber as a substitute for coarse aggregate in concrete, with the inclusion of an admixture to enhance bonding. A 1:2:4 concrete mix ratio was chosen, keeping the water-cement ratio at 0.5. Shredded rubber was incorporated as a partial substitute for coarse aggregate at varying proportions: 0%, 10%, 20%, and 30% by weight for cubes, and up to 20% for cylinders and beams. SuperLatex and Costamix 200 admixtures were added to the mix to ensure a secure bond between the rubber and concrete and to improve the overall workability and durability of the resulting material. Samples were created, including concrete cubes of 100mm dimensions, cylinders (100mm diameter x 200mm height), and beams (500mm length x 100mm height x 100mm width). These samples were cured using the ponding method for durations of 7, 21, and 28 days, depending on the sample type. The research also involved tests to determine various properties of the fresh and hardened concrete, such as workability, density, compressive strength, and deflection. The results indicated that the workability of rubberized concrete, measured through the slump test, varied between 23mm and 135mm. The compressive strength consistently decreased with increasing rubber content, with 28-day strengths ranging from 27.50 N/mm2 at 0% rubber content to 5.95 N/mm2 at 30%. Similarly, the 7-day strength diminished from 23.52 N/mm2 to 4.36 N/mm2. Furthermore, tests revealed specific gravities for fine aggregate, coarse aggregate, and shredded rubber as 2.61, 2.69, and 1.13, respectively. These findings suggested that replacing coarse aggregate with shredded rubber reduces both compressive strength and beam deflection. To conclude, while rubberized concrete, particularly with a 10% rubber content, offers the advantage of cost savings and improved energy absorption, it exhibits a decline in certain mechanical properties compared to traditional concrete.
