The feasibility study of stabilizing the automotive paint sludge by recycling, to produce green concrete blocks, considering environmental and mechanical factors

Managing hazardous waste generated by the industrial sector is a major environmental issue worldwide. In the automotive industry, a considerable amount of paint sludge waste is produced annually, and its mismanagement can adversely affect public health and the environment. Regarding the sustainable waste management hierarchy, recycling is a high priority among waste management strategies; hence, this study investigates the feasibility of recycling automotive paint sludge for producing environmentally friendly concrete, considering technical and environmental criteria. Therefore, the automotive paint sludge was analyzed, and its density and moisture content were determined. Accordingly, X-ray fluorescence, heavy metals, and gas chromatography–mass spectrometry analyses were conducted for each concrete sample. Moreover, the mechanical, structural, and physical characteristics were determined. The concrete samples were also analyzed using the toxicity characteristic leaching procedure. Results demonstrated that the concrete samples containing below 10 weight percent for paint sludge to cement ratio met the standards for construction purposes. Besides reasonable strength, concrete samples were identified as non-hazardous according to the toxicity characteristic leaching procedure results, showing the successful stabilization of hazardous contaminants of paint sludge. Using paint sludge in concrete production generally prevents resource loss and positive economic consequences, confirming its alignment with the circular economy action plan.