Physical and mechanical properties of lightweight concrete with incorporation of ceramic mold casting waste

Abstract

In the lost-wax foundry industry large amounts of ceramic mold casting waste (CMCW) are disposed of in landfills, which not only pollutes the environment but also leads to the loss of secondary resources. On the other hand, with the improvement of building style and performance, the demand for lightweight concrete is also increasing. Therefore, we recycle CMCW into lightweight concrete for environmental and economic reasons. In this study, two types of expanded clay with different sizes (2–10 mm and 10–20 mm) were used as reference aggregates. From the results, it can be seen that the density of CMCW is about four times higher than that of expanded clay, and the water absorption in 24 h is 1/4 of expanded clay. Then, expanded clay was replaced with three different weight percentages (30%, 60%, and 80%) of CMCW to prepare new lightweight concrete, which was tested for workability. After curing for 28 days at 90% humidity, four compositions were tested for their physical and mechanical properties. Finally, the results showed that with increasing CMCW content, mechanical performance also increased. With 80% CMCW in the lightweight concrete, a density of 1998 kg/m3 and compressive strength of 36 MPa were achieved.