Abstract: The experiment was carried out to study the effect of wood extractives, chamotte and CaCl2 on hydration and hardening of cement paste. It also allowed study of the effects of these additives on mechanical and physical properties of Cement-bonded Particle Board (CBPB). Homogeneous cement-bonded particleboards 12 mm in thickness were made from poplar flake with Portland cement, calcium chloride and chamotte. The CBPB was manufactured with; a wood/cement (w/c) ratio of 0.3:1 giving a specific gravity of 1.2 kg m-3; CaCl2 content as cement replacement of 3, 5 and 7%; chamotte content as cement replacement of 5, 10 and 15%. The CBPB was tested for Modulus Of Rupture (MOR), Internal Bond (IB), Thickness Swelling (TS) and Water Absorption (WA). The results showed that water-soluble wood extractive increases the hydration time of cement. It was observed that different amounts of chamotte and CaCl2 in neat cement can significantly affect the setting and hardening time. Replacement of cement with 10% of CaCl2 and 10% chamotte in boards increased the MOR and IB. It also decreased WA and TS but most importantly eliminated the inhibitory effect of wood on cement setting and hardening.