Innovative Use of Cement Kiln Dust and Blast Furnace Slag in Cementitious Materials: Assessing Strength and Durability in Harsh Environments

This study examines the mechanical properties and durability of modified cement mortar mixes that include cement kiln dust (CKD) and Ground Granulated Blast Furnace Slag (GBFS) when subjected to different environmental stressors, as salt exposure and radiation.Eleven groups of mixtures comprising 132 samples were generated to assess the impact of incorporating cement kiln dust (CKD) into cement mortar mixes as a weight-based alternative for cement. The substitution percentages were 0% for the control and 50% for all mixtures. Additionally, slag percentages of 10%, 20%, and 30% have been included in three mixtures, designated as (C6),(C7),(C8). The same percentage of slag was included into groups (C9), (C10), and (C11), which consisted of pure cement, to facilitate a comparison with the mixtures including both cement and cement kiln dust. A series of tests was conducted to assess compressive and tensile strength, workability, and resilience to extreme environmental conditions in cementitious materials with varying ratios of CKD and GBFS. Results demonstrate that the use of GBFS significantly enhances the strength and durability of the mortar in the absence of salt exposure, whilst CKD exhibits potential for partial substitution without negatively impacting performance when used at optimal levels. The study indicates that CKD and GBFS combinations have superior resistance to early hydration, higher microstructural density, and greater resilience to radiation exposure. Nevertheless, exposure to elevated salt concentrations significantly decreases strength, highlighting the necessity for optimized mix designs. This research enhances the existing knowledge on sustainable construction materials by illustrating the efficacy of CKD and GBFS in reducing the environmental impact of cement manufacturing while preserving structural integrity under adverse environmental circumstances.