Investigation of Lightweight and Green Concrete Characteristics Using Coconut Shell Aggregate as a Replacement for Conventional Aggregates

The production of sustainable and green structural concrete is getting more popular nowadays. The incorporation of agricultural waste is actively advocated in construction industries, as it makes the environment more eco-friendly. This study uses coconut shells as agro-waste as a substitute for coarse aggregate. Most tropical countries produce coconut shells at a hefty volume, but the lack of utilisation results in almost inconsequential waste material. The conventional aggregates (CA, i.e. crushed stone chips) were replaced by coconut shell aggregate (CSA) at 10%, 20%, 30%, 40%, and 50% (by weight), respectively. The rheological characteristics are measured by performing slump, density, and compacting factor tests. Various mechanical characteristics such as compressive, tensile, and flexural strength were investigated after 7, 14, and 28 days of the curing period, and the results were compared with various statistical parameters. The experimental research revealed that the workability as slump values declined gradually as the percentages of CSA increased. The strength values of concrete specimens were slightly reduced for up to 20% of CSA replacements. However, incorporating CSA at 30%, 40%, and 50% replacement provides concrete a lightweight property, and 50% replacement of CSA can still achieve the strength required to be termed as structural concrete. As a result, the replacement of CA at a hefty volume of CSA characterises the green property of concrete production.