The effects of production parameters on properties of single and 3-layer cement-bonded composites made from oil palm empty fruit bunch and tropical hardwood sawmill residue Available to Purchase

Cement bonded composites of 1250 kg/m³ were made in the laboratory either as single layer composed of exclusively oil palm empty fruit bunch (EFB); Tropical hardwood sawmill residue (THSR) or randomly mixed particles (40% of EFB and 60% of THSR oven dry wt/wt) OR of 3-layer composed of 1:2:1 ratio (for face layer of THSR; core layer of EFB and back layer of THSR particles, wt/wt, respectively). Composites were produced at 4 levels of CaCl₂ addition (0, 1, 2 and 3% wt/wt based on cement wt) and 6 levels of initial water content of the cement/aggregate mixture (2.5:1:0.5; 2.5:1:1; 2.5:1:1.5; 2.5:1:2; 2.5:1:2.5 and 2.5:1:3; ratio wt/wt based on cement wt plus oven dry wt of particles). Proximate chemical analysis of representative samples reveal hollocellulose content (77.35 and 74.11%); a-cellulose (43.51 and 52.01%); Hemicellulose (22.9 and 20.2%). Lignin (17.8 and 22.5%); Ash (0.91 and 1.85%) and solubility in Alcohol-benzene (1.6 and 3.98%); cold water (2.42 and 3.15%); Hot water (2.93 and 5.06%); and 1% NaOH (23.4 and 26.11%) respectively for EFB and THSR. Also Morphological studies reveal mean fiber length (1.06 and 1.18mm); Fiber diameter (11.75 and 17.40μm), slenderness ratio (55.79 and 35.98) and Rigidity co-efficient (0.38 and 0.47) respectively for EFB and THSR. The above make both particle sources suitable substitutes for virgin fiber/particles from hardwoods. A total of 192 composites were made representing two panels per production mix. Composites were sampled and tested in accordance with provisions of ASTM D1037-2007. Composite properties ranges are MOR (2.61–20.81 MPa); MOE (2180–5764 MPa); IB (0.28–0.75 MPa). WA (16.41–28.11%) and TS (1.26–5.98%). Properties were evaluated and only production mix that met both the requirements of International Organization for Standardization (10S 8335–1987) and Malaysian Standard Institute (MS 934–1984) were recommended. Acceptable composites were produced from production mix of initial water content ≥1.5 or 30% (based on cement wt + oven dry wt of particles, wt/wt) and 2 or 3% CaCl₂ additive in case of single layer composites while ≥ 2 or 36.36% of initial water content is required in 3-layer composite using same additive level. The effects of furnish type and composition, additive level and initial water content on properties were all found significant (P > 0.01) in factorial analysis.