Effects of some manufacturing factors on the properties of cement bonded particleboards

In this study; the performance features of three-layered cement-bonded particleboards manufactured at 1200 kg/m3 target density and 10 mm thickness from sawmill residues (poplar, spruce and fir) by using two wood-cement ratios (1/3 and 1/2), three hardener types [Al2(SO4)3, CaCl2 ve FeCl3] and silica fume (%10, 15 ve 20) as a substitute for cement, which is residue of ferrochromium factories, were determined. Chemical analyzes were performed to understand the reasons of adverse effects of wood materials on the properties of cement-bonded particleboards. The performances of produced cement boards were evaluated in aspect of physical, mechanical, thermal, flammability, formaldehyde, biological and morphological properties. Among the hardeners, the highest performances were obtained from CaCl2-added boards; while the lowest values were obtained from FeCl3-added boards. Usage of silica fume, up to 15 % as a substitute for cement, improved the overall properties of cement bonded particleboards. While spruce and fir boards showed better performances at physical properties with internal bond strength and modules of elasticity; poplar boards showed better performances at the other properties. The boards with 1/3 wood-cement ratio exhibited better performance than that of 1/2 at the physical properties (excluding thermal conductivity). Moreover, the boards with 1/2 wood-cement ratio at bending strength and the boards with 1/3 wood-cement ratio at other mechanical properties showed better performance. Key Words: Silica fume, Wood species, Wood-cemet ratio, Hardener types, Cement-bonded boards