Recycling War-Damaged Structures: Sustainable Use of Waste Aggregates in Concrete Mix Design

Abstract-Waste from construction and demolition—especially in post-conflict reconstruction—had severe implications for resources and the environment. This research used Waste Demolished Aggregate (WDA) as a replacement for natural aggregates to examine its sustainability in concrete mixtures, assessing workability and compressive strength with varying replacement percentages. The study correlated experimental results from three concrete mixing batches to provide a comprehensive overview of the impact of WDA on concrete functionality. Overall, it demonstrated how such a strategy can maximize environmental protection by minimizing landfill waste and the need for virgin aggregates, which brings economic benefits through such reconstruction. Minimal differences in workability were observed across the three batches based on concrete mixing slump test results. The first batch slump ranged from 75mm to 80mm, the second batch from 79mm to 80mm, and the third batch from 79mm to 82mm. However, at higher WDA percentages, there was a slight difference in workability and slump. The trend observed in compressive strength tests for the three batches indicated a declining pattern of strength with higher WDA content, consistent with the literature, which attributed this observation to the porous structure and irregular shape of WDA particles. The statistical testing demonstrated a significant reduction in strength at both the 25% and 50% WDA replacement levels. The findings indicated that 25% WDA and 50% WDA resulted in a reduction of compressive strength of approximately 23% and 31%, respectively, compared to natural aggregates. These results had significant implications for the use of WDA in structural applications. Although non-structural applications for WDA such as drainage systems, pathways or non-load-bearing walls suggest potential, WDA may well have limited application at best in structural concrete without further adjustment of the mix to overcome strength losses.