Mechanical and durability properties of concretes produced by two-step CO₂ mineralization

^a Department of Civil Engineering, National Institute of Technology Silchar, Assam - 788 010, India
^b Corrosion and Materials Protection Division, CSIR – Central Electrochemical Research Institute, Karaikudi, Tamil Nadu - 630 003, India

^* Corresponding author: mlvprasad@civil.nits.ac.in

Published online: 19 December 2025

Abstract

The current ways of using CO₂ in concrete include carbonation conditioning of recycled aggregates and carbonation curing alone. These procedures have several drawbacks, including the need for a large carbonation chamber and the low diffusion rate applied to the outer surfaces only. CO₂ mineralization during concrete mixing is an innovative CO₂ utilization method; in this process, CO₂ reacts with calcium-rich cementitious materials and beneficially impacts cement hydration, producing more hydration products and forming nano-scale calcium carbonate, thus filling the minute pore. Hence, utilizing CO₂, a major greenhouse gas, in manufacturing concrete provides a two-fold benefit. The characteristics of CO2-mineralizing concrete are investigated in this work; a two-step CO₂ mineralization process in concrete was used. The outcome of the work reveals that incorporating a small proportion of CO₂ into concrete substantially improves its performance. There was a considerable increase in mechanical characteristics at a CO₂ dosage of 0.2% of cement utilized; an 18.7%, 8.3%, and 7.4% increase in compressive, tensile and flexural strength was observed at 28 days of testing. Additionally, CO₂ mineralization significantly improves the long-term durability of concrete. Hence, the present approach improves concrete performance and helps reduce CO₂ emissions.