A study into flexural, compressive and tensile strength of coir-concrete as sustainable building material

Abstract

Coir has been known as a potential natural fiber for many sustainable construction material developments due to its wide availability and sustainable resource of coconut tree. This research study aims to investigate the flexural, compressive and tensile properties of concrete incorporating coir fiber and to find the fiber content which gives optimum results. In this study, coir concrete specimens were cast and tested with variations of fiber content of 0%, 0.25%, 0.5%, 0.75%, and 1% by weight of aggregates. Flexural test was conducted based on SNI 4431:2011, compressive test was conducted based on SNI 1974:2011 and tensile test was conducted based on SNI 2491:2014. Slump tests and unit weight showed reduced values when fiber content was increased. Flexural, compressive and tensile strengths of coir-concrete at a 28-day curing were optimum for the variation with 0.25% fiber content. Compressive strength of control concrete at 28 days was approximately 23 MPa while BS-0.25 was 27.5 MPa. Flexural strength of control concrete was 5 MPa while BS-0.25 was 6 MPa. Tensile strength of control concrete was 3 MPa while BS-0.25 was 2.5 MPa. Results from the study showed that the presence of 0.25% fiber (by total weight of aggregate) in the concrete gives approximately 19% improvement in 28 days compressive strength and flexural strength.