CO2 sequestration in cement-based materials during mixing process using carbonated water and gaseous CO2

Jacek Kwasny, P. A.Muhammed Basheer, Mark I. Russell, William Doherty, Kieran Owens, Neil Ward

    Research output: Contribution to conferencePaperpeer-review

    6 Citations (Scopus)

    Abstract

    This paper presents selected findings from a recently completed research project, aimed at the investigation of CO2 sequestration in cement-based materials during the early stages of hydration when the cement paste is being mixed. Portland cement pastes were carbonated during the mixing process, using both carbonated water and gaseous CO2, and their properties were compared to the control non-carbonated mix. All mixes were prepared in a purpose-designed chamber that permitted carbonated water and gaseous CO2 to be mixed with the cementbased materials during the mixing process, without losses of CO2 to the external environment. Temperature measurements taken of the samples during mixing were used to evaluate the influence of carbonation on the properties of fresh pastes and their early hydration. Changes in the composition of the hardened pastes, due to the above-mentioned processes, were studied using thermogravimetric (TG) analysis, X ray diffractometry (XRD), and Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDXS) were used to investigate physical (morphological) and chemical differences between non-carbonated and carbonated samples. It was found that, when compared to the non-carbonated mixes, the rate of the initial hydration of carbonated pastes increased, but the later hydration rate was decreased dramatically. TG, XRD, and FTIR spectroscopy revealed a substantial increase in the CaCO3 content and decrease in the Ca(OH)2 content in carbonated pastes. SEM showed substantial differences in the microstructure of the carbonated mixes when compared to the noncarbonated ones; needle- and lichen-like hydrates, with a high content of CO2, covered the surface of the fractured carbonated samples.

    Original languageEnglish
    Pages72-79
    Number of pages8
    Publication statusPublished - 01 Jan 2014
    Event4th International Conference on the Durability of Concrete Structures, ICDCS 2014 - Indiana, West Lafayette, United States
    Duration: 24 Jul 201426 Jul 2014

    Conference

    Conference4th International Conference on the Durability of Concrete Structures, ICDCS 2014
    CountryUnited States
    CityWest Lafayette
    Period24/07/201426/07/2014

    Keywords

    • Carbonated water
    • Carbonation
    • Cement hydration
    • FTIR
    • SEM
    • TG
    • XRD

    ASJC Scopus subject areas

    • Civil and Structural Engineering
    • Building and Construction

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