InterPore2025

Mechanical Performance of Accelerated Carbonated Concrete

21 May 2025, 10:05

1h 30m

Poster Presentation (MS25) Advances in Carbon Mineralization: Unveiling Multiscale Geo-processes and Coupled Mechanisms Poster

Speaker

Geng Niu (Duke University)

Description

As the global demand to limit the heating of the planet to 1.5 to 2.0 °C by 2050 becomes increasingly urgent, the CO${}_2$ mineralization reactions of Portland cement concrete (i.e., carbonation) have emerged as a large-scale CO${}_2$ capture and sequestration solution. Portland cement, the primary ingredient in concrete and the second most widely used material after water, has the potential to mineralize CO${}_2$ into stable calcium (and magnesium) carbonates. While carbonation is reported to refine pore structure and enhance its mechanical performance, its effect on the relationship among deviatoric stress, material deformation, and failure mechanisms of the concrete remains insufficiently understood. In this study, we investigate the coupled effects of accelerated carbonation on the mechanical performance of concrete using both an Environmental Triaxial Automated System (ETAS) and a TESCAN UniTOM XL X-ray micro-computed tomography (X-CT) scanner.
To analyze mechanical performance, ETAS (triaxial tests) were conducted, and results were used to construct P-Q stress state diagrams to reveal the relationship between mean normal and deviatoric stresses. Further analysis using the Mohr-Coulomb failure criterion was used to quantify critical parameters, providing detailed insights into the failure mechanisms and stress behavior of carbonated concrete. X-CT was used to both monitor the evolution of carbonation depth before ETAS testing and failure cracks on the same samples after ETAS. This non-destructive, high-resolution technique facilitated continuous monitoring of the spatial and temporal progression of carbonation, including the pore structure alterations and the distribution of carbonation products. Additionally, X-CT was used to capture and analyze the interplay between carbonation and fracture propagation, offering a comprehensive understanding of these coupled processes. This research advances the fundamental understanding of accelerated carbonation in concrete in support of the transition toward carbon-neutral solutions in the built environment.