Title:
Examining Carbonation of Calcium Silicate-Based Cements in Real Time Using Neutron Radiography
Author(s):
Rita Maria Ghantous, Margaret N. Goodwin, Mehdi Khanzadeh Moradllo, Sean Quinn, Vahit Aktan, O. Burkan Isgor, Steven Reese, and W. Jason Weiss
Publication:
Materials Journal
Volume:
120
Issue:
6
Appears on pages(s):
47-60
Keywords:
calcium silicate cements; carbonation; diffusion coefficients; drying; neutron radiography
DOI:
10.14359/51739146
Date:
12/1/2023
Abstract:
Carbonatable calcium silicate cement (CSC) is a promising
approach to reducing the carbon footprint associated with concrete
production. Carbonatable CSC gains strength by reacting with
carbon dioxide (CO2). While the concept of carbonation is well
known, more information on the curing process is needed. This
study focuses on studying the impact of drying time, carbonation
duration, and degree of saturation (DOS) on the carbonation reaction
of CSC mortar. Samples were exposed to different drying durations
at controlled environmental conditions to reach various DOSs
ranging from 100 to 0%. The samples were then exposed to carbonation under the same environmental conditions for different durations. Neutron radiography (NR) was performed on the samples
during drying to determine the DOS corresponding to various
drying durations. NR was also used during the carbonation period
to determine the degree of carbonation (DOC) in real time. The
impact of carbonation on the diffusivity of water vapor (Dh) and
pore size distribution of CSC-based samples was examined using
dynamic vapor sorption (DVS). It was concluded that the carbonation reaction increased as the DOS decreased from 100 to 40%. The carbonation reaction ceased for samples with DOS values less than 6% DOS. It was also concluded that as the DOC increased,
the pore structure was refined, which led to a decrease in the Dh of
the CSC mortar samples.