Compressive and Flexural Strength Development of Oil Palm Frond Fibre-Reinforced Sandcrete Blocks: ANOVA, Tukey and Regression Analysis

Abstract

Oil palm frond fibre (OPFF) offers a potential agricultural-waste reinforcement for sandcrete, but its influence on compressive and flexural strength may differ with fibre dosage and curing age. This study evaluated the strength development of sandcrete containing 0, 0.5, 1.0, 1.5 and 2.0% OPFF by mass of cement. Forty-five 150mm cube specimens and 30 beam specimens were produced, with three replicate specimens for each dosage and curing condition. Compressive strength was measured at 7, 14 and 28 days, while flexural strength was measured at 7 and 28 days. Mean strength, standard deviation, percentage change relative to the control, one-way analysis of variance (ANOVA), Tukey HSD and linear regression were used to characterise dosage effects. At 28 days, compressive strength was 5.711 N/mm² for the control and 3.644, 4.069, 2.992 and 1.613 N/mm² for 0.5, 1.0, 1.5 and 2.0% OPFF, respectively. OPFF content significantly affected compressive strength at 7, 14 and 28 days (p < .001), with significant negative regression relationships at all ages (R² = .933, .934 and .870, respectively). Flexural strength increased numerically with OPFF content, reaching 2.078 N/mm² at 7 days and 3.243 N/mm² at 28 days for C2.0, compared with 1.100 and 1.689 N/mm² for the control. However, the flexural regression relationships were not statistically significant (p = .065 and .057). The findings demonstrate that OPFF dosage produced contrasting compressive and flexural responses, supporting the need to evaluate both properties when characterising fibre-reinforced sandcrete.