International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 7, Issue 1, pp: (103-110), Month: April 2019 - September 2019, Available at: www.researchpublish.com
Waste/Recycled Plastics in Concrete Yoon-Si Lee Associate Professor, Civil Engineering and Construction, Bradley University, Peoria, IL, USA
Abstract: While the use of plastics has gradually increased in our daily lives due to its user-friendly features, lightness and cost-effectiveness, scientific and engineering communities have raised their concerns in recent decades regarding the harmful effects caused from the usage and disposal of plastics on our environment. Also, from an environmental point of view, concrete production heavily contributes to greenhouse gas emissions and the majority of construction materials are produced from natural resources. Therefore, there exists a need for developing sustainable concrete that leaves less carbon footprint and requires fewer natural resources. In this regard, utilizing waste/recycled plastics in concrete can be a viable alternative that offers obvious ecological and environmental benefits. Numerous researchers and engineers have investigated the feasibility of using various types of plastics in concrete production. Since different types of plastics possess engineering properties that are different from conventional constituents of concrete, it is important to understand how adding plastics would alter the characteristics and behavior of concrete. This paper presents a methodical review on recent researches that used waste/recycled plastics as an additive or a partial replacement of aggregates in concrete, and discussed their effects on various properties of concrete. Keywords: Waste Plastic; Recycled Plastics; Concrete; Compressive Strength; Flexural Strength.
I. INTRODUCTION With the rapid technological advances and improvement in standard living, the quantity of plastic consumed throughout the world has gradually increased in various fields for domestic, industrial and commercial purposes such as packaging, manufacturing, building and construction, and automotive and industrial applications. The usage of plastic is so wide spread that it nowadays seems as if plastics have become integral part of our daily lives. This is due to a numerous advantages of plastic over other materials including its user-friendly features, lightness, flexibility, and cost-effectiveness. While the use of plastics provides a wide range of benefits to our society, scientific and engineering communities have begun to raise their concerns in recent decades regarding potential harmful effects of plastic usage on our environment. These increased concerns have prompted numerous engineers searching for ways to recycle and reuse these waste plastics. Construction industry has been also facing a few issues associated with the global carbon footprint and limited natural resources. Concrete production heavily contributes to greenhouse gas emissions and the majority of construction materials are produced from natural resources. Therefore, there exists a need for developing sustainable concrete that causes less greenhouse gas emissions and requires fewer natural resources. In this regard, the use of waste/recycled plastics as aggregate in concrete production may be a viable alternative that offers obvious ecological and environmental benefits. It would not only reduce the exploitation of natural resources but address the environmental concerns such as a disposal of non-biodegradable waste plastics, a limited landfill space, and emission of harmful chemicals. A recent study estimated that over 20 billion tons of concrete are annually produced worldwide, which makes it the second most consumed substance following fresh water [1]. In a typical concrete production, aggregates occupy approximately ¾ of concrete volume and 25% to 35% of aggregates are comprised of sand. Some researchers predict that more than 800 million tons of sand could be saved per year in the US by replacing 10% of the sand used in concrete with finely ground plastic particles [1]. Concrete production contributes approximately 4.5% of the world’s human-induced carbon dioxide emissions. Scientists and engineers believe that a substantial amount of carbon emission and global carbon footprint can be prevented if natural aggregates are replaced by recycled materials such as plastics in concrete production [2]. Different types of plastics have their unique engineering properties that are different from conventional constituents of concrete mix. Therefore, before the use of plastics in concrete is considered, it is important to understand how adding
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