Quantifying CO2 Mineralization in Cement-Based Materials: Measurement Methods and Challenges

This presentation was given at the Oct 2025 American Concrete Institute Convention in the technical session Low-Carbon Cement and Concrete Technologies, Measurements, and Standards that took place on Oct 26, 2025.Carbonation of cement-based materials is both a natural process that offsets emissions and an emerging route for deliberate CO₂ utilization, yet accurately quantifying mineralized CO₂ remains a challenge. This presentation reviews the principles, limitations and comparative performance of key methods: quantitative X-ray diffraction (QXRD), thermogravimetric analysis with mass spectrometry (TGA+MS), scanning electron microscopy (SEM), pressure calcimetry, and carbon/sulfur combustion-infrared absorption. Case examples show how different techniques handle amorphous carbonate phases, leading to systematic variation in reported values. A comparison outlines trade-offs in accuracy, speed, and applicability, offering guidance for selecting appropriate approaches and integrating results into carbon accounting frameworks.