Induction furnace steel slag is a secondary product obtained when molten steel is separated from the impurities in the steel-producing furnaces. Though numerous studies have been published on the mechanical strength of concrete/mortar made with steel slag as fine aggregate, relatively few studies focus on the shrinkage, durability (i.e., porosity, water absorption, and resistance to chloride penetration) at ambient temperature, and especially the mechanical and durability performances after exposure to elevated temperatures. Within this context, the present study investigates mechanical strength, shrinkage, and durability of mortar made with different contents of steel slag powder (SSP) at two different water-to-cement (w/c) ratios before and after exposure to elevated temperatures (120, 250, 400 and 600 °C). Mortars made with SSP showed significantly higher mechanical strength and better durability than mortar made with 100% natural sand (control mortar). Compressive, tensile, and flexural strength increased by 45%, 72% and 56%, respectively, when SSP entirely replaced natural sand. Porosity, water absorption, and chloride penetration decreased by 42%, 61% and 52%, respectively, for 100% SSP mortar. Furthermore, the shrinkage of the mortar decreased with increasing percentages of SSP. Conversely, residual compressive strength after heat exposure was lower for 100% SSP mortar than for the control mortar. Therefore, this study presents a first step towards the successful utilization of SSP in cementitious mortar.@en

This study evaluates the mechanical, durability, and residual compressive strength (after being exposed to 20, 120, 250, 400 and 600 °C) of mortar that uses recycled iron powder (RIP) as a fine aggregate. Within this context, mechanical strength, shrinkage, durability, and residual strength tests were performed on mortar made with seven different percentages (0%, 5%, 10%, 15%, 20%, 30% and 50%) of replacement of natural sand (NS) by RIP. It was found that the mechanical strength of mortar increased when replaced with up to 30% NS by RIP. In addition, the increase was 30% for compressive, 18% for tensile, and 47% for flexural strength at 28 days, respectively, compared to the reference mortar (mortar made with 100% NS). Shrinkage was observed for the mortar made with 100% NS, while both shrinkage and expansion occurred in the mortar made with RIP, especially for RIP higher than 5%. Furthermore, significantly lower porosity and capillary water absorption were observed for mortar made with up to 30% RIP, compared to that made with 100% NS, which decreased by 36% for porosity and 48% for water absorption. As the temperature increased, the strength decreased for all mixes, and the drop was more pronounced for the temperatures above 250 °C and 50% RIP. This study demonstrates that up to 30% RIP can be utilized as a fine aggregate in mortar due to its better mechanical and durability performances. @en