In a cement board (CB) composite, fibres reinforce the board. It is because the length of the fibres significantly impacts the strength of the CB composite. Nonetheless, the physical properties of the CB are also an important aspect when dealing with the quality control of the final product. This study investigates the effects of various fibre lengths in CB fabrication on its physical properties, including the cement-hydration rate, tensile strength, density stability and thickness swelling (TS). Oil palm empty fruit bunch (OPEFB) fibres at different lengths are used based on the mesh retained size of R7M, R14M, and R30M. The OPEFB-CB mixture used in this research is 3:1 (cement: fibre ratio), with a target density of 1,300 kg/m3. The sample is compressed using a 1000 psi cold-compression load to achieve the desired composite thickness of 12 mm. This research revealed that the longest fibres retained on the R7M mesh with an average length of 5 mm resulted in lower density and the highest TS value. Meanwhile, lower dimensional stability was achieved by OPEFB-CB composites using fibre that retained on the R14M and R30M, having an average length of 3 mm and 1 mm, respectively. Based on the results, the optimum fibre length recommended in the fabrication of OPEFB-CB composites is processed fibres retained on the R14M sieve with an average length of 3 mm. This recommendation is made based on the most stable density and lowest TS results achieved by the R14M retained fibres which is in the range of 1,231–1,309.4 kg/m3 and TS of 0.65 %.

Oil palm empty fruit bunch (OPEFB) fibre has been introduced to replace current materials mainly such as wood fibre that was not encouraged to be used as a construction sourced due to the sustainability of wood fibres and prevents the high demand of forest resources. In Malaysia, the cultivation and use of the oil palm and its products have increased because of high market demand, and this has resulted in the abundant availability of the empty fruit bunch (EFB). The EFB fibre geometry and particle size in the EFB cement bonded boards have their own mechanical and physical properties. The fibre to cement ratios are also different to boards made out of wood fibres. This experimental research work has been conducted by other researchers. The larger the particle size, the better the compaction of EFB-CB effects of cement setting by much larger surface on the board area. Short particles lead to low values of modulus of elasticity (MOE), caused by inadequate of empty fruit bunch (EFB) particles to cement substances. Nevertheless, short particles avoid large void spaces and irregularities towards cement board. Using different Cement-EFB fibre ratio has direct influence on thickness swelling (TS), modulus of rupture (MOR), and modulus of elasticity (MOE). Strength of EFB-CB depends on the bonding between fibre and cement composites. The pre-treatment fibre was indicated where the EFB fibre composite were dimensionally stable for bonding mechanisms and could be used for both interior and exterior building utilizations based on the tested physical and mechanical properties on cement-boards.