Improvement in Impact Resisting Capacity of Concrete Using Tyre Rubber Dust

In concrete, the most voluminous constituent is aggregate and depleting resources of aggregate compels us to think about its substitute which may be a recycled or waste material. On the other hand, huge quantity of used tyres from vehicles, are causing problems in their disposal. Therefore, in present study, an effort has been made on the use of waste rubber dust as partial replacement of fine aggregate in concrete for improving its impact resistance. Four concrete designs were prepared for M20, M25, M30 and M35 using IS: 10262-2009 guidelines. Specimens were produced control mixes and %, 10 and 15% replacement of fine aggregates by rubber dust. The specimens were concrete cubes of 150 mm size for compressive strength tests and circular disc for impact tests. The rubber surface was pre treated with sodium hydroxide (NaOH) of 1N solution for 20 minute and then left to surface dry prior to mixing in concrete. This treatment modified the rubber surface, allowing the rubber to better adhere with cement paste. Various tests were carried out and results were compared between control concrete and concrete prepared with various percentage of fine aggregates replaced with rubber dust. Results show that as the replacement percentage of fine aggregate increases, compressive strength of concrete decreases and a maximum reduction of 42% in compressive strength is found in concrete, made with 15% replacement of fine aggregate by rubber dust. Also, the workability of fresh concrete diminishes drastically. However, with the increase in rubber dust percentage, impact resisting capacity of the concrete improved.