Trigger-responsive carbonation control in concrete through bio-mineralisation microcapsules and adaptive durability design

Abstract Concrete remains the most widely used mass-produced engineering material, and the carbonation of the calcium hydroxide and calcium silicate hydrate phases of hardened cement paste by reaction with atmospheric carbon dioxide is among the most important factors governing concrete’s durability in service. Over the past decade, a parallel field of research has reconceived carbonation as a controllable process rather than a purely destructive phenomenon, proposing that its rate, depth, and self-healing capacity can be adjusted through chemical, biological, and mechanical “triggers” built into the cementitious matrix itself. This article synthesises three routes to trigger-responsive carbonation control — microbially induced calcium carbonate precipitation (MICP), encapsulated stimulus-responsive chemistries, and adaptive durability design — and proposes a unifying Trigger–Response Transfer Function (TRTF) that maps environmental inputs (relative humidity, pH, CO 2 partial pressure, mechanical strain, temperature, and chloride concentration) to controlled-mineralisation outputs. The synthesis draws on a PRISMA-style systematic search of Scopus, Web of Science, the ASCE Library, and ScienceDirect for the period 2010–2025 (293 records screened, 178 retained) and integrates evidence from accelerated carbonation chambers, MICP column experiments, microcapsule release kinetics, and coupled finite-element transport models. Across ureolytic MICP studies, the reported recovery of CO2-uptake capacity in spore-bearing matrices spans 12–41% of unhealed controls, with a pooled mean of 28 ± 11% (n = 18 studies), the scatter reflecting differences in spore strain, dosage, and curing protocol. Three failure modes — false-positive trigger release, alkalinity collapse, and chloride–carbonation coupling — are identified and reformulated as quantitative design constraints, a prioritised testing roadmap is proposed, and the framework is aligned with United Nations Sustainable Development Goals 9, 11, 12, and 13. The TRTF provides a quantitative basis for future trigger-responsive concrete research and for standardising the reporting of healing-performance claims.