Impact resistance of concrete containing waste rubber fiber and silica fume

• Impact resistance of concrete containing waste rubber fiber and silica fume assessed.
• Drop weight test, flexural loading test and rebound test conducted.
• Relationships established between results of these tests.
• Waste rubber fibers increase the impact resistance and ductility of concrete.
• Silica fume increases the impact resistance of rubberized concrete.

High impact resistance and greater energy absorption capacity are desirable properties for concrete. Innovative and sustainable materials may be used to improve these properties. In the present study, the effect of replacement of fine aggregates by waste rubber fibers on the impact resistance of concrete has been assessed. Silica fume has also been considered as replacement of cement. Six replacement levels of rubber fiber (0%, 5%, 10%, 15%, 20% and 25%) and three replacement levels of silica fume (0%, 5% and 10%) have been considered for three different water cement ratios. Impact tests on concrete have been conducted by three different techniques; drop weight test, flexural loading test and rebound test. Relationships between impact test results of drop weight test, flexural loading test and rebound test have also been established. In view of large variation of impact values, a two-parameter Weibull distribution is adopted to analyze the experimental data of drop weight test. The study demonstrates that the waste rubber fiber can be used as a sustainable material to improve the impact resistance and ductility of concrete. The study also demonstrates that the silica fume improves the impact resistance and reduces the ductility of rubber fiber concrete.