Digital and Intelligent Technologies for Construction and Demolition Waste Sorting: A Systematic Mapping Review of Research Maturity, Circularity Outcomes, and Industry Gaps

Construction and demolition waste (CDW) sorting is increasingly supported by digital and intelligent technologies, yet their functional coverage, maturity, circular economy (CE) contribution and alignment with industrial practice remain fragmented. This review systematically mapped the field using a PRISMA-based search, with 396 publications forming the broader bibliometric corpus. Within this corpus, 204 publications were retained for the scoped review, comprising 185 primary technical studies and 19 review articles. An illustrative ZenRobotics/Kuljetusrinki case was examined separately within a case-bounded academic-industry comparison. Artificial intelligence, computer vision, and sensing dominated the technical literature, particularly for identification, classification, localisation, and segmentation, while fewer studies progressed to robotic handling, physical separation, and integrated system functions. Among the 185 primary technical studies, validation remained concentrated at lower maturity levels, with 54.1% at laboratory maturity, 6.5% testing fully realistic CDW conditions, 18.9% reporting external or independent validation, and 3.2% reporting industrial deployment. Although 94.1% of these studies had a direct CE link, specific CE and sustainability outcome-related evidence such as recovered material quality, reuse, and landfill diversion was reported less consistently than technical performance. The case-bounded comparison showed that several capabilities investigated separately across the academic literature were integrated within the selected operational case, while independently verified operational and CE outcomes remained limited. These findings highlight the need for robust, integrated and operationally validated CDW sorting systems that connect emerging technologies with measurable recovery, material quality and circular outcomes under practical operating conditions.