Feasibility study on partial replacement of fine aggregates by recycled plastic waste in concrete

Abstract

Concrete is the most extensively used construction material in the world and is the second only to water as the most heavily consumed substance, with about six billion tons produced every year. It has emerged as the dominant construction material for the infrastructure needs of the 21st century. Concrete is a composite material that consists essential of a binding medium, such as a mixture of Portland cement and water, within which are embedded particles or fragment of aggregate, usually a combination of fine and coarse aggregates. Plastics are a vast group of synthetic or semi-synthetic materials that are often made of polymers. Because of their plasticity, plastics can be moulded, extruded, and pressed into solid objects of different sizes. Its extensive use is due to its flexibility, as well as a number of other properties such as light weight, durability, and low manufacturing costs. The high use of plastics has resulted in an increase in solid waste, with domestic waste accounting for a significant portion of it. Since this waste is not biodegradable and takes up a lot of space, it is considered a serious environmental problem. To overcome these adverse effects, recycling plastic waste and using it in concrete can be an effective way to protect the environment. In this study, an attempt was made to experimentally evaluate the mechanical properties of concrete with recycled HDPE plastic wastes. The control mix was made and the other mix containing 8.8% of plastic waste in order to compare their characteristics, it was observed that the workability of partial replacement mix has decreased, the compressive strength too has decreased by 5.7%, and even the water absorption percentage decreased by 0.1 % compared to the concrete with 0% plastic wastes. The maximum compressive strength of a control mix after 28 days of curing was 29.7 MPa while the other mix with 8.8% of plastic wastes was 28 MPa. The incorporating of plastic waste can slightly reduce compressive strength due to its lower bonding capacity in the mix but this substitution helps reduce plastic pollution.