Review of deterioration mechanisms and durability performance mapping of sustainable SCM concrete in wastewater environments

The concrete industry contributes significantly to global CO₂ emissions, with ordinary Portland cement (OPC) being a major source. Reducing the proportion of OPC through the incorporation of supplementary cementitious materials (SCMs) has emerged as a critical sustainability strategy for lowering the carbon footprint of concrete production. This is particularly important in large-scale infrastructure, such as wastewater and sewage treatment plants, where biogenic sulphuric acid and external sulphate attack shorten service life. In such cases, OPC replacement strategies must be sustainable and durable. Despite the demonstrated benefits of SCMs in reducing embodied carbon, durability performance varies widely depending on SCM type, reactivity, and substitution level, necessitating systematic evaluation. This review consolidates current knowledge on deterioration mechanisms and benchmarks OPC-SCM binders through bibliometric analysis and composition-performance mapping. Results show that SCMs such as fly ash (used at replacement levels of 10-60%), ground granulated blast furnace slag (used as replacement levels up to 75%), silica fume (3-30%), metakaolin (5-30%), and waste glass powder (5-30%) improve resistance to sulphuric acid and sulphate attack by reducing Ca(OH)₂ availability, refining pore structure, and limiting secondary gypsum and ettringite formation. Materials-phase emissions compiled in this review indicates that fly ash and silica fume have the lowest values (∼0.01 kg CO_2-eq/kg), followed by waste glass powder (∼0.02 kg CO_2-eq/kg), with biomass fuel ash, calcined clay, and GGBS also substantially lower than OPC. By linking binder chemistry to durability performance, this review provides a mechanistic screening framework which will aid in selecting durable, low-carbon binders for wastewater infrastructure, and identifies priority research directions for emerging SCMs and optimised multicomponent blends.