Mineral additives from Ukrainian industrial waste in cement concrete: a critical review of fly ash, metakaolin, and microsilica for circular-economy and reconstruction applications

Abstract

This critical review summarizes the current knowledge regarding supplementary cementitious materials (SCMs) with a focus on the specific context of these raw materials and production conditions in Ukraine. Based on screening using PRISMA guidelines, a structured literature search in Scopus, Web of Science, and Google Scholar (2014–2025; final search date 30 April 2025) was performed, and 312 records were screened, 87 records were retained after eligibility screening, and 33 primary studies were included in the final synthesis (supported by 9 standards and policy documents cited as context; the inclusion count has been corrected after a re-audit of the screening log). Chemical-composition data measured by the authors for clinker from the four main cement plants in Ukraine and for fly ash from Kyiv TPP-5 are added to the review. When ordered by reported pozzolanic activity determined by the 28-day saturated-lime absorption test (CaO uptake at 28 days), the three SCMs are ranked as microsilica (≈330 mg CaO/g) > metakaolin (≈190 mg CaO/g) > fly ash (≈45 mg CaO/g). Literature show the compressive strength gains from 25–30 % fly ash replacement are negative at 1–7 days but positive (+10–15 %) after 28–90 days due to pozzolanic reaction.