Research Outputs (Civil and Environmental Engineering)

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Information regarding content on this collection please contact : Salome Potgieter by email : salome.potgieter@wits.ac.za or Tel : 011 717 1961

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Browsing Research Outputs (Civil and Environmental Engineering) by Keyword "Concrete"

Now showing 1 - 3 of 3
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    The effects of supplementary cementing materials in modifying the heat of hydration of concrete.
    (Springer, 2009) Ballim, Y.; Graham, P.C.
    This paper is intended to provide guidance on the form and extent to which supplementary cementing materials, in combination with Portland cement, modifies the rate of heat evolution during the early stages of hydration in concrete. In this investigation, concretes were prepared with fly ash, condensed silica fume and ground granulated blastfurnace slag, blended with Portland cement in proportions ranging from 5% to 80%. These concretes were subjected to heat of hydration tests under adiabatic conditions and the results were used to assess and quantify the effects of the supplementary cementing materials in altering the heat rate profiles of concrete. The paper also proposes a simplified mathematical form of the heat rate curve for blended cement binders in concrete to allow a design stage assessment of the likely early-age time–temperature profiles in large concrete structures. Such an assessment would be essential in the case of concrete structures where the potential for thermally induced cracking is of concern.
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    Modeling the cooling of concrete by piped water.
    (American Society of Civil Engineers., 2009) Myers, T.G.; Fowkes, N.D.; Ballim, Y.
    Piped water is used to remove hydration heat from concrete blocks during construction. In this paper we develop an approximate model for this process. The problem reduces to solving a one-dimensional heat equation in the concrete, coupled with a first order differential equation for the water temperature. Numerical results are presented and the effect of varying model parameters shown. An analytical solution is also provided for a steady-state constant heat generation model. This helps highlight the dependence on certain parameters and can therefore provide an aid in the design of cooling systems.
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    Modelling the cooling of concreate by piped water
    (2009-03-25) Myers, T.G.; Fowkes, N.D.; Ballim, Y.
    Piped water is used to remove hydration heat from concrete blocks during construction. In this paper we develop an approximate model for this process. The problem reduces to solving a one-dimensional heat equation in the concrete, coupled with a first order differential equation for the water temperature. Numerical results are presented and the effect of varying model parameters shown. An analytical solution is also provided for a steady-state constant heat generation model. This helps highlight the dependence on certain parameters and can therefore provide an aid in the design of cooling systems.