Title:
Using X-Ray CT to Understand Greenhouse Gas and Water Migration in Cement-Based Materials
Author(s):
Laura Dalton
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
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DOI:
Date:
10/29/2020
Abstract:
From previous analysis on water sorption kinetics in air-entrained mortar specimens purged with different gas phases (CO2, CH4, and N2), results showed the higher the gas solubility, the faster cement-based materials reached saturation. CO2-purged specimens absorbed water 200 times faster than N2- and CH4-purged specimens. These tests revealed the gas type present in the void space plays an integral role in the rate of water movement through cement-based materials. In a recent follow-up study, how the CO2 state (gas, liquid or supercritical) and different degrees of saturation (0, 50, or 100%) influence the transport properties in cement-based materials was studied using a high temperature and high-pressure system housed in a micro-computed tomography scanner. Preliminary findings show the degree of saturation is an integral factor in the rate of carbonation and transport through cement-based materials. The CO2 state also affects the rate of transport with supercritical CO2 carbonating more rapidly than other states at low degrees of saturation. These findings have implications for predicting mass transport in cement-based materials for the long-term safety of carbon storage structures.