INVESTIGATION MECHANICAL & DURABILITY PROPERTIES OF CRUMBED RUBBER CONCRETE CONTAINING RECYCLED CONCRETE AGGREGATE

Abstract

The concrete construction industry requires huge amount of natural resources. Currently natural resources are depleting while demand for concrete is increasing. Several studies are focused to solve this issue. The waste rubber has become a huge environmental issue worldwide. Researchers identified a sustainable way of reusing waste rubber by recycling it to Crumbed Rubber and partially replacing that for fine aggregate in concrete. However, with introduction of this crumbed rubber to concrete, the compressive strength of developed concrete was decreased. Therefore, the main aim of this research is to improve compressive strength in Crumbed Rubber Concrete using recycle concrete aggregate. Other than that, some fresh properties, mechanical & durability properties were investigated. 15 percent of replacement of fine aggregate by rubber has been identified as an optimum replacement level by other studies. Therefore, this study was conducted for 15% volume based fine aggregate replacement. As recycle aggregate act as a cementitious binder, it was added in 10,15,20,30 percent of weight basis for cement. The w/c ratio was kept constant at 0.57. Maximum 10 mm aggregate was used in the study. The crumbed rubber replacement resulted in 60 percent decrement in compressive strength and recycled aggregate in all levels resulted in a higher compressive strength than rubber-only concrete but got optimum increment in 20 percent and starts to decrease. Same as compressive strength, splitting tensile, flexural strength increased to optimum values with 20 percent of recycled aggregate. The available design codes were used to calculate theoretical values using experimental values to investigate adequacy of these mixes. The investigate revealed that available standard guidelines cannot be used to predict the behavior of crumbed rubber concrete containing recycled concrete aggregate. This study proves that addition of recycle aggregate to crumbed rubber concrete improves its strength. However, the durability and dynamic properties of this developed concrete needs to be investigated.