Wood ash as a supplementary cementing material in foams for thermal and acoustic insulation

This study characterizes a Portland cement based cellular system prepared with a preformed foam. Wood ash, locally sourced from pulp and paper mills, was first characterized and later, blended at up to 20% of the binder. The resulting mixtures were cast at three densities between 1000 and 1400 kg/m(3) and examined for mechanical, thermal and acoustic properties. A phase analysis was performed using X-ray diffraction to identify the components of the wood ash and again, in the hydrated system. The thermal constants were measured using the Transient Plane Heat Source (TPS) technique per ISO 22007-2. Sound absorption and noise reduction coefficients were evaluated using the impedance tube method per ASTM C384-04. The results show that although blending wood ash led to lower compressive strength and elastic modulus, the drop in strength was within 20%. While not as effective in reducing noise, the wood ash led to 20% lower thermal conductivity. These findings offer wood ash as a viable, replenishable and sustainable substitute for Portland cement in insulating foams. (C) 2019 Elsevier Ltd. All rights reserved.