Designing sustainable partition wall blocks using secondary materials: A life cycle assessment approach

As considerable amount of waste materials and by-products are generated from the urban and industrial production systems, efforts to utilize such materials resourcefully have received increasing attention in order to increase the use of recycled materials and reduce landfill disposal. In addition, construction products often induce significant environmental burden due to the use of emission-intensive materials. Therefore, continuous scientific efforts have been devoted in resource-efficient design with the incorporation of such secondary materials to help save the primary resources and reduce the environmental impacts. In this study, cement-free partition wall block is developed through a number of strategies, whereby emission-intensive Ordinary Portland cement is completely substituted by waste materials and supplementary cementitious materials, and this together with the use of recycled aggregates can make the blocks produced entirely based on secondary materials. The required mechanical performance of the blocks produced under different strategies is verified through laboratory tests. The carbon reduction potentials for such strategies are evaluated through the life cycle assessment (LCA) technique. The LCA results show that partition wall blocks produced with concrete slurry waste (CSW), fly ash and fine recycled concrete aggregates can reduce up to 82% of the total carbon emissions than other strategies. On the other hand, the reuse of CSW in the production of partition wall blocks can potentially save 80,000 m³ of landfill space and US$4 million of costs associated with landfill disposal in Hong Kong annually. To maximize the advantages of such secondary resources in partition wall blocks production, it is imperative to establish industrial symbiosis networks with relevant supply chain and to adopt the developed partition wall blocks widely in practice.