Compatibility of some tropical hardwoods species with portland cement using isothermal calorimetry

Ten Mozambican hardwood species were tested for their compatibility with tw o classes of Portland cement. Instantaneous heat flux of cement hydration w as measured by isothermal calorimetry. A wood-cement compatibility factor w as determined. These tests identified species compatible with cement withou t needing any water treatment (Amblygonocarpus andongensis and Brachystegia speciformis) as well as the species becoming compatible after a simple col d- or hot-water extraction of water-soluble components of wood (Pterocarpus angolensis, Kaya nyasica, Erythrophleum suaveoleuns, Albizia adianthifolia , and Sterculia appendiculata). Millettia stuhlmannii and Julbernadia globi flora showed considerable compatibility improvement following extraction wi th an NaOH solution (10 g/L). Afzelia quanzenzis, however, appeared to requ ire more treatments to make it sufficiently compatible with Portland cement . Special procedures and treatments must be applied in order to make wood-c ement composites from several mixed species.