Influence of crumb rubber on the response of concrete beams against low velocity impact

Abstract

High impact resistance and energy absorption capacity are desirable characteristics of concrete for several structural applications such as roadside barriers, bridge columns, rockfall protection barriers, and industrial buildings. Crumb rubber has been proven to enhance these characteristics of concrete. In past, numerous experimental investigations have been performed to study the mechanical properties of rubberized concrete. However, a detailed inspection of rubberized concrete under low velocity impact is still lacking. Also, the design guidelines for the employment of crumb rubber in concrete have not been explored. In the current study, the influence of partial replacement of sand with crumb rubber on the impact response of concrete has been studied. Concrete mixes with different proportions of sand replacement (5–30% by volume) have been prepared. The impact tests are conducted using drop impact test setup on concrete beams of dimension 500 mm × 100 mm × 100 mm. The specimens are subjected to an impact of 6 kg mass from an elevation of 500 mm. The results reveal that the replacement of sand with crumb rubber enhances the flexibility, energy absorption capacity, and peak impact force. Although, a curtailment in the compressive strength, elastic modulus, and split tensile strength is observed. Moreover, the microstructural properties of rubberized concrete are also investigated using SEM (Scanning Electron Microscopy), and tentative design guidelines are proposed for selecting an optimum percentage of crumb rubber in concrete.