Volume 3, Issue 1

    Comparative Analysis of the Influence of Sodium and Potassium Silicate Solutions on the Kinetics and Products of Slag Activation

    (Received 20 January 2014; accepted 6 May 2014)

    Published Online: 2014

    CODEN: ACEMOAD

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    Abstract

    This paper primarily explores the influence of the alkali cation (Na or K) on the reaction kinetics, product formation, gel structure, and mechanical properties of alkali activated slag systems. For the same activator Ms, i.e., molar SiO2–M2O ratio (M = Na or K), a shorter induction period, a larger acceleration peak, and consequently, a higher amount of total heat release under isothermal conditions is observed for the K-silicate activated slag pastes. The early-age compressive strengths in these systems roughly relate to the heat release response. The later-age (7 days and beyond) compressive strengths are observed to be higher for the Na-silicate activated systems, which is corroborated by: (1) higher amounts of C–(A)–S–H gel in this system indicated by a thermal analysis-based approximate quantification method, and (2) higher combined intensities of Q1 and Q2 structures that point to increased degrees of reaction, and lower amounts of unreacted slag obtained from 29Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra also show evidences of Al-substituted C–S–H gel, with a higher amount of substitution when Na-silicates are used.


    Author Information:

    Dakhane, Akash
    Graduate Student, School of Sustainable Engineering and the Built Environment, Arizona State Univ., Tempe, AZ

    Peng, Zihui
    Graduate Student, Department of Physics, Arizona State Univ., Tempe, AZ

    Marzke, Robert
    Associate Professor, Department of Physics, Arizona State Univ., Tempe, AZ

    Neithalath, Narayanan
    Associate Professor, School of Sustainable Engineering and the Built Environment, Arizona State Univ., Tempe, AZ


    Stock #: ACEM20140005

    ISSN: 2165-3984

    DOI: 10.1520/ACEM20140005

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    Author
    Title Comparative Analysis of the Influence of Sodium and Potassium Silicate Solutions on the Kinetics and Products of Slag Activation
    Symposium , 0000-00-00
    Committee C01