The Carbonation of Calcium-Silicate-Hydrate C-S-H in Cement Mortar Studied Using Thermal Analysis and Gas Pycnometer: Determination of the Quantity of Calcium Carbonate Produced and the Increase in Molar Volume

Abstract:

The objective of this work was to examine the microstructural changes caused by the carbonation of normalised cement mortar. Samples were prepared and subjected to accelerated carbonation at 20°C, 65% relative humidity and 20% CO₂ concentration. The main contributions of this study were: 1) a new way to determine separately the amount of calcium carbonate CaCO₃ produced by the carbonation of portlandite Ca (OH)₂ and that associated with the carbonation of calcium-silicate-hydrate C-S-H using only thermal analysis; 2) determination of the increase in the molar volume of the calcium-silicate-hydrate C-S-H due to carbonation using gas pycnometer, which indicated an increase of about 39 cm³ for 1 mole of C₃S₂H₃ carbonated. The results indicated that the amount of CaCO₃ produced by the carbonation of C-S-H is higher than that produced by the carbonation of portlandite.

• Periodical: Advanced Materials Research (Volumes 931-932)
• Pages: 411-415
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.931-932.411
• Online since: May 2014
• Authors: Son Tung Pham*, William Prince
• Keywords: Calcium-Silicate-Hydrate, Carbonation, Cement Mortar, Gas Pycnometer, Thermal Analysis

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