Abstract:
This project focused on a possibility of using industrial wastes as raw materials in gypsum-based building materials, which mainly consisted of 75-90 wt% flue-gas desulfurization, FGD gypsum, and other wastes. This work also aimed to improve their properties, including strength, durability, water absorption and water resistance. There were 4 more wastes employed in the gypsum mixtures: ladle furnace slag from steel recycling, glass cullet powder from safety glass finishing process, diatomite from brewery production and rooftile sludge from roof tile manufacturing process. The work found that the mixture between FGD gypsum and other wastes resulted in the gypsum-based bodies with various properties, depending on the degree of hydration and pozzolanic reactions as well as type, content and natures of the combined wastes. A mixture containing rooftile sludge gained higher strength due to its fibrous nature. Ladle furnace slag developed strength in the beginning and became poorer later due to water swelling. Meanwhile, glass cullet and diatomite led to superior strength and durability. Low water absorption and water resistance were also achieved. In comparison, glass cullet waste provided superior water resistance to the diatomite one.