Effect of High Temperature Exposure on Bond Properties of Steel Deformed Rebar Embedded in Self-Consolidating Concrete Containing Copper Slag as Fine Aggregate

Despite the extensive studies in the literature on using copper slag (CS) as fine aggregate within normal concrete to alleviate the thermal cracking of samples exposed to high temperatures, very limited investigations concentrated on self-consolidating concrete (SCC). Moreover, there is no precise study to determine the effect of CS on thermal damage mitigation at the rebar/SCC interface. Hence, the present study intends to experimentally determine the residual bond properties of steel rebar embedded in SCC specimens exposed to high temperatures. Accordingly, three different percentages of 35%, 70%, and 100% of normal fine aggregate replacement by CS were considered. Also, different high-temperature exposures of 350 degrees C, 550 degrees C, and 750 degrees C were selected for simulating thermal damage. Bond parameters were extracted from the bond-slip envelope curves to compare the results, including average bond stress, maximum bond stress (or bond strength), residual bond stress, and bond energy. Generally, findings revealed that using CS causes an increase in bond properties in undamaged specimens at ambient temperature and that a 53.6% bond strength improvement was observed for 100% CS replacement as compared to the reference SCC mixture. However, in thermally-damaged SCC specimens, the optimal dosage of 35% was found for fine aggregate replacement by CS.