Reimagining sustainable sulfur concrete: A systematic review of sulfur, waste integration, and durability

Sulfur concrete (SC) - a thermoplastic, waterless composite in which molten sulfur-based binder replaces Portland cement - is attracting growing research attention as a sustainable construction alternative capable of superior performance in chemically aggressive environments. This systematic literature review synthesises evidence from 127 sources (2000-2025), examining three interlinked dimensions: (i) the role of waste and industrial by-product materials as aggregate and filler substitutes; (ii) the influence of aggregate type, morphology, and grading on mechanical and microstructural performance; and (iii) durability under acid, saline, and freeze-thaw exposures. A transparent, PRISMA-aligned screening and classification protocol - here used as a structured review design rather than a statistical Design of Experiments - guided the identification, screening, and thematic grouping of 51 primary experimental studies. Industrial by-products - including ground-granulated blast-furnace slag (GGBFS), waste marble powder (WMP), fly ash, rubberised crumb rubber, ceramic powder, and electrolytic manganese residue (EMR) - can match or exceed conventional sand in mechanical strength and chemical resistance when the mix is appropriately designed for the intended service environment; however, the magnitude and even the direction of this benefit depend on binder modification, aggregate grading, and cooling conditions, and should not be assumed to hold across all SC systems or exposures. Compressive strengths across the reviewed literature span from approximately 14 MPa to 86 MPa, a range driven primarily by system design rather than any single variable. In acidic and chloride environments, SC mixes with waste fillers lose 90-95% less mass than Portland cement concrete. Freeze-thaw performance, however, remains contested: low water absorption does not guarantee frost stability, and binder-aggregate thermal mismatch can generate internal microcracks even in seemingly impermeable systems. Four critical research gaps emerge: absence of field-scale validation data; insufficient study of mixed waste streams; unresolved fire and flame safety in structural applications; and lack of standardized mix design protocols for waste aggregate variability. Future research priorities are proposed with a structured research agenda.