Properties of Coconut Shell Aggregate Concrete: A Review

The demand for concrete has increased since it became an unavoidable construction material worldwide. Coarse aggregate is one of the main ingredients of concrete. Depletion of aggregate deposits occurs due to continuous extraction of aggregates, which leads to environmental degradation and thus ecological imbalance. Therefore, trends in concrete technology are currently directed toward searching for alternative sustainable materials for aggregate in order to minimize over reliance on natural resources. Many substitute materials such as aggregates from industrial wastes and byproducts are used for production of concrete. Coconut shell is a waste material from agricultural industries and available in plenty throughout the tropical regions worldwide. Coconut shells are used for many useful purposes, but most of the coconut shell wastes are yet to be utilized commercially. A promising solution to the challenges in coconut waste management involves coconut shell as aggregate in concrete. Many researches were conducted on coconut shell aggregate concrete in the last decade. This paper presents an overview of physical, mechanical and chemical properties of coconut shells, followed by a discussion on the physical, mechanical, bond and durability properties of coconut shell aggregate concrete. Structural behaviors such as shear, flexure and torsion of coconut shell aggregate concrete are also discussed. Some applications of the coconut shell aggregate concrete are also highlighted. The current understanding of coconut shell aggregate concrete provides basis for further research in this field.