Application of recycled aggregates generated from waste materials towards improvement in acoustical and thermal conductivity of concrete

Abstract

The construction sector, in addition to being very important for the economy of several countries, also creates a large amount of construction waste which has a significant impact on the environment. Usage of alternative coarse aggregates (ACA) materials for partial replacement or complete replacement of coarse aggregates can be identified from multiple sustainable sources including solid waste generated on a regular basis. There are limited studies that have explored the utility of waste materials for coarse aggregate (WMCA) in improving concrete qualities like compressive strength, thermal conductivity, and acoustic properties. Previous researchers have conducted several feasibility studies of using construction-and-demolition-waste (CDW) in engineering works, which lead economic and environmental sustainability in the construction sector. Studies show that the thermal transmittance (U-Value) of concrete, which varies between 0.62 to 3.33 W/m2K, is affected by the type of aggregates being used. It has also been demonstrated that concrete to be a good sound insulator due to its high density, but a poor sound absorber with a reflection of up to 99% of sound energy. Opportunities for usage of waste materials like coconut shells, crumb rubber aggregate (CRA) from scrap tyres, glass, plastic wastes. e-waste, construction and demolition waste (CDW), polystyrene, styrofoam and polystyrene as partial replacement of CA need investigation in depth. Some previous studies, that examined the utility of alternate materials like scarp tyres, broken bricks, CDW etc. used as partial replacement of CA, have shown promising results. This article presents a literature review on the production and utilization of waste materials for coarse aggregate in concrete for improving the acoustical and thermal properties. Summarily, this review may help in alleviating concerns of consumers and further promote the use of recycled aggregate on a larger scale in civil engineering.