Examination of the permeability of rubberized concrete with different water/cement ratios and their resistance against acid and sulfate attack

This study aims to examine the permeability and acid and sulfate attack of waste rubber-substituted concrete containing recycled rubber in three different grain size classes (chips, crumb and powder) with two different water/cement (w/c) ratios (0.4 and 0.5). Waste rubber at different ratios (0%, 4%, 8%, 12%, 16%, 20%, and 24%) was used in concrete by replacing fine and coarse aggregates. Sorptivity, electrical resistivity, and acid and sulfate attack tests were conducted on concrete cured for 90 days. Although the capillarity coefficient values increased with the waste rubber replacement ratio increase, a decrease occurred after the 20% waste rubber replacement ratio. In 12% waste rubber-substituted concrete (0.4WR12) with a water/cement ratio of 0.4, the electrical resistivity value (8.3 kΩ.cm) was the highest, and concretes with low permeability could be produced. As a result of the use of 16% waste rubber in the concrete, 75% less compressive strength loss was observed after the acid attack compared to the control concrete. In concrete with a water/cement ratio of 0.5, when the waste rubber ratio increased by up to 16%, the compressive strength losses caused by the sulfate attack decreased dramatically (95.76% less) compared to the control concrete. The rubberized concrete with a water/cement ratio of 0.5 showed high resistance to acid and sulfate attacks. The experiment results showed that 12% to 16% waste rubbers are ideal ratios. In this study, the water/cement ratio was a valuable parameter for the waste rubber ratio in rubberized concrete.