Influences of cement brands and mixing ratios on the physico-mechanical properties of cement bonded particleboards made of wood particles of Gmelina arborea, Afzelia africana and Triplochiton scleroxylon

Cement bonded particleboards (CBPs) were produced of wood particles of Gmelina arborea, Afzelia africana and Triplochiton scleroxylon using two brands of ordinary portland cement manufactured by two different domestic cement companies operating in Nigeria known as Dangote PLC and Lafarge Company. The admixture of wood particles and cement for production of the CBPs were done at mixing ratios of 1:1, 1:1.5 and 1:2 (weight to weight basis). The properties such as water absorption and thickness swelling at 24 hours, density, modulus of rupture (MOR), modulus of elasticity (MOE) and impact bending strength were determined. The results of the study reveal that the density ranged from 0.61 to 0.92 g/cm3. Meanwhile, water absorption and thickness swelling were found to be 30.34 to 72.44 % and 11.43 to 10.77 % at 24 hours, respectively. The bending properties obtained from the laboratory tests ranged from 115.77 to 826.55 N/mm2 and from 1157.70 to 4773.38 N/mm2 for MOR and MOE, respectively, while impact bending strength ranged from 41.70 to 238.49 N/mm2, respectively. As the cementious content increases from 50 % to 66.3 % and wood content decreases from 50 % to 33.4 %, the properties such as density, MOR, MOE and impact bending strength increased, while water absorption and thickness swelling decreases. The statistical results showed that such factors as wood species, cement type and mixing ratio had significant influence on the physical and mechanical properties of CBPs. The study reveals that CBPs made of wood particles of Triplochiton scleroxylon and Dangote cement brand at the ratio of 1:2 were more dimensionally stable, denser and stronger while CBPs of wood particles of Afzelia africana were stiffest and most rigid. As concluded, cement brand had significant importance in qualities of CBPs, which can be attributed to chemical compositions found in materials used. Keywords: cement, physical, mechanical, wood, particleboards, mixing ratio