Review on Thermal Conductivity of Recycled Concrete

Abstract:

Recycled aggregate concrete （RAC） is different from ordinary concrete in its internal microstructure， mechanical and thermodynamic properties due to the addition of recycled concrete aggregates （RCA）. At present， there have been many studies on the mechanical properties of RAC， but less attention has been paid to its thermodynamic properties. In this paper， effects of several important factors such as physical properties and replacement level of RCA， recycled concrete powders， and service temperature on the thermal conductivity of RAC are reviewed. Based on the experimental data in literature， an empirical equation for predicting the thermal conductivity of RAC is proposed. Existing studies show that the porosity of RCA affects the thermal conductivity of RAC. The incorporation of RCA and recycled concrete powder as well as the increase of ambient temperature can lead to a significant decrease in the thermal conductivity of concrete and with 100% recycled fine aggregate， the reduction of thermal conductivity can reach 48%. Functionalized RAC together with an enhanced mechanical performance would promote a wider industrial application and lead to less CO2 emission of the construction industry.

Key words:recycled concrete;thermal conductivity;recycled aggregate;recycled powder;functionalization