Volume 38, Issue 5 (September 2010)

    The Application of Various Indicators for the Estimation of Carbonation and pH of Cement Based Materials

    (Received 17 February 2009; accepted 12 February 2010)

    Published Online: 2010

    CODEN: JTEOAD

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    Abstract

    Carbonation decreases the pH of the concrete and breaks the passivity of reinforcing steel. Therefore, carbonation is related to potential rebar corrosion even though carbonation itself does not directly damage the integrity of the concrete. The phenolphthalein method, which is the most often used method of determining carbonation, however, has a reliability problem. Therefore, this research mainly focuses on the use of various indicators to find the possible substitutes for phenolphthalein. The early carbonation and pH of the carbonated specimen was also investigated using various indicators. It was found from the results that thymolphthalein was the best substitute for phenolphthalein, and a combination of phenolphthalein and thymolphthalein, tropaeolin O, and indigo carmine enabled us to estimate the early carbonation. This research also reported the successful application of various indicators which can be extended for the pH estimation of solid mortar specimen.


    Author Information:

    Yu, Myoung-Youl
    Research Professor, Research Institute of Biotechnology, Dongguk Univ., Seoul,

    Lee, Jae-Yong
    Associate Professor, Division of Architecture, Pukyung National Univ., Busan,

    Chung, Chul-Woo
    Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana Champaign, Urbana, IL


    Stock #: JTE102382

    ISSN: 0090-3973

    DOI: 10.1520/JTE102382

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    Author
    Title The Application of Various Indicators for the Estimation of Carbonation and pH of Cement Based Materials
    Symposium , 0000-00-00
    Committee C01