Cement-bonded composites made from tropical woods: Compatibility of wood and cement

Compatibility and hydration of Ordinary Portland Cement (OPC) with 15 commercially available tropical wood species were investigated by studying the heat release during cement hydration in various wood species, chemical compositions and microstructure of the hydrated products, and the effects of various solution treatments of wood particles on the compatibility of wood-OPC composites. It was found that (1) low molecular weight carbohydrates and hemicelluloses directly contributed to the inhibition of hydration of cement in wood–cement composites; (2) wood–cement compatibility reduced as the wood content of the mixture increased but the rate of change varying considerably from one to another species; (3) overall ranking order of the wood–cement compatibility at 5% by weight wood content was mouvingui > nkanang > ngollon > sapel > tali > padouk > bibolo > ayous > eyong > frake > bête > bilinga > doussie > iroko > moabi, with movingui having an average compatibility factor 96% even the wood content is greater than 5% while doussie reaching a compatibility factor only 7.7% at 1.8% by weight wood content; (4) X-ray diffractogram analysis indicated that the presence of Ca(OH)2 reduced by 50% for the hydration product in wood–cement composites compared to that in pure cement paste, suggesting the change of structure of hydrated products due to inhibition of wood; (5) wood–cement compatibility was improved significantly by pre-treating wood in solutions with the saturated lime (Ca(OH)2) solution being most efficient and CaCl2 least efficient; and (6) the untreated wood inhibited cement setting by dissolving extractives shortly after the dormant period. The findings of this study provide fundamental and essential database and technologies for exploiting tropical wood species and correctly utilising the 15 tropical wood species with cement as value added commercial products in construction.

► 15 tropical wood species were examined for manufacturing cementitious composites.
► Paper determined key parameters for hydration and bonding of 15 species with OPC.
► Low molecular weight carbohydrates varied considerably among 15 tropical species.
► Compatibility factor of wood-OPC decreased with the increase of solubility content.
► Extracting in H2O, CaCl2, MeO and Ca(OH)2 significantly increased the compatibility.