Rights statement: This is the author’s version of a work that was accepted for publication in Cement and Concrete Composites. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Cement and Concrete Composites, 126, 2022 DOI: 10.1016/j.cemconcomp.2021.104336
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Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Evolution of ITZ and its effect on the carbonation depth of concrete under supercritical CO2 condition
AU - Bao, H.
AU - Xu, G.
AU - Yu, M.
AU - Wang, Q.
AU - Li, R.
AU - Saafi, M.
AU - Ye, J.
N1 - This is the author’s version of a work that was accepted for publication in Cement and Concrete Composites. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Cement and Concrete Composites, 126, 2022 DOI: 10.1016/j.cemconcomp.2021.104336
PY - 2022/2/28
Y1 - 2022/2/28
N2 - In this paper, supercritical carbonation tests of concrete specimens with different water-to-cement ratios are carried out. In the test, the thickness of interfacial transition zone (ITZ) of the concrete is determined by the distribution of Ca/Si ratio across the interface between the coarse aggregate and cement paste. The microhardness distribution, microstructure and porosity of the ITZ before and after supercritical carbonation are analyzed. A geometrical and physical model considering the distribution of porosity, coarse aggregates, ITZ, and the supercritical carbonation of concrete is proposed, by which cracks, pores, calcium carbonates, and C-S-H gel at the interface of coarse aggregates and cement paste can be studied. The overall microstructures are relatively compacted after supercritical carbonation. The thickness of ITZ of concrete is reduced from 47-79 μm to 35–51 μm after supercritical carbonation. The average value and variance of carbonation depth of concrete increase with the increase of the thickness and porosity of ITZ. Comparing the carbonation results of concrete with different thicknesses and porosity of ITZ, it appears that porosity of ITZ has greater impact on the carbonation depth of concrete.
AB - In this paper, supercritical carbonation tests of concrete specimens with different water-to-cement ratios are carried out. In the test, the thickness of interfacial transition zone (ITZ) of the concrete is determined by the distribution of Ca/Si ratio across the interface between the coarse aggregate and cement paste. The microhardness distribution, microstructure and porosity of the ITZ before and after supercritical carbonation are analyzed. A geometrical and physical model considering the distribution of porosity, coarse aggregates, ITZ, and the supercritical carbonation of concrete is proposed, by which cracks, pores, calcium carbonates, and C-S-H gel at the interface of coarse aggregates and cement paste can be studied. The overall microstructures are relatively compacted after supercritical carbonation. The thickness of ITZ of concrete is reduced from 47-79 μm to 35–51 μm after supercritical carbonation. The average value and variance of carbonation depth of concrete increase with the increase of the thickness and porosity of ITZ. Comparing the carbonation results of concrete with different thicknesses and porosity of ITZ, it appears that porosity of ITZ has greater impact on the carbonation depth of concrete.
KW - Carbonation depth
KW - Concrete
KW - Geometrical and physical model
KW - Interfacial transition zone
KW - Supercritical carbonation
KW - Calcium carbonate
KW - Cements
KW - Concrete aggregates
KW - Concrete testing
KW - Microstructure
KW - Porosity
KW - Silicon
KW - Testing
KW - Cement paste
KW - Coarse aggregates
KW - Condition
KW - Geometrical models
KW - Physical modelling
KW - Supercritical
KW - Supercritical CO 2
KW - Carbonation
U2 - 10.1016/j.cemconcomp.2021.104336
DO - 10.1016/j.cemconcomp.2021.104336
M3 - Journal article
VL - 126
JO - Cement and Concrete Composites
JF - Cement and Concrete Composites
SN - 0958-9465
M1 - 104336
ER -