Heavyweight concrete has been used for different types of radiation shielding applications. Research studies have been performed to determine the mechanical properties of heavyweight concrete. However, relatively little information is available on the fire performance of heavyweight concrete after exposure to elevated temperatures. This study investigates the effects of elevated temperatures (25, 300, 500, 600 and 800 °C) on the residual density, compressive strength and water sorptivity of heavyweight barite concrete. A control mix of normal granite concrete was produced for comparison. The influence of using treated cathode ray tube (CRT) funnel glass cullets as a fine aggregate replacement in the barite concrete was also examined. The results show that the type of aggregate used had a significant influence on the residual properties of concrete mainly because of their physical and mineralogical transformation upon heating. Incorporation of CRT glass in barite concrete seemed to increase the risk of explosive spalling after exposure to 500 °C. However, as the temperature was increased from 600 to 800 °C, the loss of mechanical properties of the concrete containing CRT glass was smaller because of the molten glass being able to fill the pores/cracks, which was followed by resolidification upon cooling. Copyright © 2013 John Wiley & Sons, Ltd.