Study on thermal properties of recycled aggregate concrete and recycled concrete blocks

This paper investigated the thermal properties of recycled aggregate concrete (RAC) and recycled concrete block. Considering the effect of four factors, an orthogonal test was conducted to study the thermal conductivity of RAC. The thermal conductivities of large particle recycled aggregate concrete (LRC) and recycled brick concrete (RbC) were also tested at different replacement ratio of recycled aggregate. By defining an influence coefficient c, the effect of recycled concrete aggregate (RCA) on thermal conductivity of RAC was better explained. A modified formula was also proposed to calculate the thermal conductivity of RAC based on that of normal concrete. The thermal resistance of recycled concrete block was calculated, and an experiment on the heat transfer coefficient of recycled concrete block wall in practical engineering was conducted. The study shows that the recycled coarse aggregate has the greatest influence on thermal conductivity of RAC. There is a significant linear relationship between the influence coefficient c and the thermal conductivity of RAC. The results calculated from modified formula for thermal conductivity of RAC agreed basically with the test results.