Effect of partial replacement of aggregate with oil palm shell on compressive and flexural strength of fiber concrete

Considerable innovation has been applied to concrete material to achieve specific properties such as density, strength, environmental sustainability, cost-effectiveness, among others. This study focused on the replacement of a portion of the aggregate with oil palm shell (OPS) to utilize previously underutilized waste. Concrete containing OPS typically exhibits reduced compressive strength compared to standard concrete. To enhance the compressive and flexural strength of OPS-infused concrete, the introduction of fibers was explored as an innovative measure. A particular focus was placed on using fibers from discarded masks due to the Covid-19 outbreak in Indonesia and globally. The non-biodegradable nature of polypropylene fibers in these masks necessitates further measures to minimize waste. Different proportions of OPS were incorporated into the concrete mix: 0%, 25%, 50%, 75%, and 100%, with each mix incorporating 0.20% mask fiber and 0.25% superplasticizer. Compressive strength testing employed cylindrical specimens with a diameter of 75 mm and a height of 150 mm, while flexural strength was assessed using beam specimens measuring 100 x 100 x 500 mm. The baseline compressive strength for concrete without OPS measured 17.76 MPa. The results of flexural strength testing revealed the highest value of 1.67 MPa for the 0% OPS mix and the lowest, 0.49 MPa, for the 100% OPS mix. Statistical analysis via analysis of variance (ANOVA) highlighted a notably significant correlation between the treatment combinations involving compressive strength and the replacement of OPS as coarse aggregate.