Concrete change: Exploring future scenarios for the supply of supplementary cementitious materials in the EU

Cement, a crucial material in the construction industry, contributes about 8 % of global greenhouse gas emissions. While substituting clinker with supplementary cementitious materials (SCMs) is a key mitigation measure, SCM availability is expected to decline. In this work, a 2023–2050 scenario analysis predicts a decline in the supply of common SCMs in the EU, with fly ash supply decreasing from 8.5 Mt in 2025 to 1.9–2.7 Mt in 2035 and 0–1.1 Mt in 2045, and granulated blast furnace slag supply decreasing from 18 to 19 Mt in 2025 to 6.9–11.4 Mt in 2035 and 0–3.2 Mt in 2045. Thus, the supply of conventional SCMs will be insufficient to meet demand, even if demand for ordinary Portland cement is assumed to decline significantly in 2025–2045. Efforts to develop the production and logistics of alternatives in order to sustain a lower clinker-to-cement ratio are therefore needed. • Alternative binders key to reduce GHG emissions related to cement and concrete. • We explore future supply trends of fly ash and GBFS as cement clinker alternatives. • Show how supply of fly ash and GBFS is set to decline rapidly in the coming decades. • The results highlight need to scale up efforts to develop the production alternatives.