Influence of elevated temperature on properties of radiation shielding concrete with electric arc furnace slag as coarse aggregate

The development of value-added materials from by-product of the steel-making process can promote sustainability in construction to move towards a circular economy. The use of Electric Arc Furnace (EAF) steel slag as heavyweight coarse aggregate to develop sustainable radiation shielding concrete could provide both technical and economic benefits with less environmental impact. This contribution investigates the behaviour at high temperature of a sustainable radiation shielding concrete. Thermal behaviour of EAF slag concrete was compared to another heavyweight concrete made of barite aggregates and to a normal-weight concrete. On one hand, the thermal stability of the three different aggregates was determined via simultaneous Thermogravimetry and Differential Scanning Calorimetry analyses and visual observations after 10 degrees C/min heating. On the other hand, the evolution of thermal conductivity of concretes during heating, the residual mechanical properties and the assessment of potential spalling occurrence were investigated. Stereo-microscope and Scanning Electron Microscope pictures provide additional explanations by showing the paste-aggregate interface after heating at 450 degrees C. The results indicated that EAF concrete displayed less strength reduction at increasing temperature. This improved behaviour is attributed to both the strong bond between the paste and the aggregates, and the better thermal behaviour of the EAF slag aggregates compared to barite aggregates. (C) 2020 Elsevier Ltd. All rights reserved.