Compositional analysis and quantification of construction waste from residential building projects

Abstract

The increasing construction waste in urban areas poses environmental and economic challenges, necessitating the characterization and valorization of these materials to unlock their economic potential. This study aims to characterize construction waste materials in selected construction building projects in Abuja, Nigeria. Field observation and experimental methods were used to obtain data for the study. Construction waste materials from selected Abuja building projects were sorted and weighed to identify dominant components. Physical and chemical characteristics of these materials (cementitious waste, concrete debris, wood, metal) were determined through tests including specific gravity, XRF, XRD, and SEM-EDS. The research classified and analyzed these materials to inform potential valorization strategies. The specific gravity of construction waste samples varied widely, ranging from 1.0543 to 2.5560, indicating differences in material density and quality. XRF results showed that the dominant oxides identified in the samples are SiO₂ (64.40%), CaO (9.66%), and Al₂O₃ (6.78%), which collectively account for over 80% of the total oxide composition. The XRD analysis confirmed the presence of crystalline phases like quartz, calcite, and feldspar, while SEM micrographs revealed compact microstructures with irregular particle surfaces. The major oxides present in the waste samples are characteristic of materials with significant siliceous and aluminosilicate phases, suggesting strong potential for pozzolanic activity. The mineralogical composition and compact microstructures of the samples support the material’s potential reusability in blended construction materials. Overall, the results show that only certain construction waste fractions, like chiselled concrete and mortar/concrete waste, have densities comparable to natural aggregates, while others need processing or limited use in lower-grade construction. The results of this study can guide government and private sector stakeholders in crafting tailored waste management policies, ultimately helping to mitigate environmental degradation in Abuja and comparable cities.