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The scarceness of virgin resources and sustainable management of waste materials in high-density city arouse heightened focus on new technology development for waste recycling and local utilization. Wood waste recovery from construction activities and upcycling into secondary products allow the substitution of virgin resources and minimize the environmental burdens within the frontier of industrial ecology. This study assessed the technical viability and environmental sustainability of cement-bonded particleboards (CBPs) produced with recycled wood aggregates and alternative binder; and compared the performance of its counterpart produced with virgin wood and ordinary binder using experimental analysis and life cycle assessment (LCA). The experimental results showed acceptable mechanical performance of the developed CBPs in compliance with the required standards. Adoption of carbon dioxide curing technology further enhanced the durability of the developed CBPs. Although similar greenhouse gases (GHGs) emission was observed for imported conventional CBPs and locally produced CBPs with alternative materials, the considerations of direct carbon sequestration and landfill avoidance contributed to a 9% reduction of the total GHGs compared to conventional CBPs. The LCA results also demonstrated that substantial amount of GHGs can be potentially saved depending on the recycling rates of wood waste in Hong Kong. Hence, technological innovation can effectively address problem of wood waste disposal and enhance material utilization and sustainability of the construction industry. [ABSTRACT FROM AUTHOR]

• Evaluated the techno-environmental feasibility of using natural pozzolana in concrete production, • Comparable compressive strength was found for the use of VA against conventional SCMs, • VA significantly reduced environmental impacts of concrete compared to OPC and other SCMs, • 11–30% lower GHG emissions was found for VA concrete compared to other cementitious materials. With increasing environmental sustainability concerns in the construction industry and a demand for producing more durable and sustainable concrete, effort is devoted to producing concrete with Ordinary Portland cement (OPC) being substituted by alternative binder materials. By considering the compressive strength, the comprehensive environmental performance of natural pozzolana in concrete was evaluated comparatively by developing six mix-designs of concrete with OPC, and commonly used industrial by-products as supplementary cementitious materials such as fly ash (FA) and ground granulated blast furnace slag (GGBS) based on the lifecycle assessment (LCA) approach. The results show that comparable compressive strengths can be achieved for the use of 20% and 30% volcanic ash (VA) against conventional SCMs. Using the volume as functional unit, the LCA results have demonstrated that higher environmental savings are associated with VA concrete compared to that of OPC, GGBS (30%) and FA (25%), but almost similar when 50% GGBS is used. For example, 15–24% and 10–19% lower global warming potential are associated with VA concretes compared to that of OPC and FA concretes, respectively, but much higher saving is found when considering the strength of the concrete, as they are about 11–12%, 10–11% and 29–30% compared to that of GGBS, FA and OPC concretes, respectively. The results can be used as valuable guidelines for VA-based in sustainable concrete production, which would further enhance the sustainability of the concrete industry. [ABSTRACT FROM AUTHOR]

Quarry dust, a by-product of stone grinding, cutting, sieving and crushing, is abundantly available and can create many on-site and off-site environmental problems. This paper investigates the feasible utilization of quarry dust as an alternative to river sand in the production of lightweight foamed concrete (LFC). LFC with a density of 1300 ± 50 kg/m 3 and fixed cement/filler ratio of 1:1 were adopted in this study. Quarry dust was used to replace sand at ratios of 75% and 100%, and four different water-to-cement ratios (w/c) of 0.52, 0.54, 0.56 and 0.58 were studied and compared. For a given w/c ratio, it was found that the use of high volume quarry dust could reduce the fluidity and increase the compressive strength and the thermal conductivity of LFC. However, no significant decrease of compressive strength was observed with the increase of w/c ratio, probably due to the reduction of foam volume requirement in the system. Life cycle assessment results indicated that the LFC containing quarry dust possessed less environmental impact in terms of lower energy consumption and lesser amount of greenhouse gases emission. [ABSTRACT FROM AUTHOR]