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首页> 外文期刊>Construction and Building Materials >How sulfates and increased temperature affect delayed ettringite formation (DEF) in white cement mortars.
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How sulfates and increased temperature affect delayed ettringite formation (DEF) in white cement mortars.

机译：硫酸盐和温度升高如何影响白水泥砂浆中延迟的钙矾石形成（DEF）。

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摘要

In this study, white cement CEM I and white limestone cement CEM Il-LL A and hi with 15%, 25% and 35% limestone substitution were studied. The way delayed ettringite is forming due to exposure to increased temperature (50 ℃) and external sulfate attack was examined in mortar samples which were immersed for 90 days in three different solutions: (a) saturated solution Ca(OH)_2 at 50 ℃, (b) saturated solution of Ca(OH)_2 at 20 ℃ and (c) 5% w/w Na_2SO_4 solution at 50 °C. During this period mortar samples were visually observed regularly while their expansion was estimated on a weekly basis by measuring the change of length with a micrometer. At the end of the 90-days period the compressive strength of the mortars was determined and the deterioration products were identified through means of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and thermogravimetric analysis (DTG). The results of this study show that DEF occurred in two forms. Samples cured at increased temperature contained DEF type I, which caused mediocre expansion and damage. Samples cured at increased temperature in the presence of sulfates produced DEF type Ⅱ, which caused significant damage on the surface and exhibited high expansion.
机译：在这项研究中，研究了石灰石替代率为15％，25％和35％的白水泥CEM I和白石灰石水泥CEM II-LL A和hi。由于暴露于升高的温度（50℃）中而形成延迟的钙矾石的形成方式，并在将砂浆样品浸入三种不同溶液中90天的砂浆样品中检查了外部硫酸盐的侵蚀：（a）50℃的饱和Ca（OH）_2溶液， （b）20℃时的Ca（OH）_2饱和溶液和（c）50℃时的5％w / w Na_2SO_4溶液。在此期间，定期目视观察砂浆样品，同时每周用千分尺测量其长度变化来估算其膨胀。在90天的最后阶段，确定了砂浆的抗压强度，并通过X射线衍射（XRD），扫描电子显微镜（SEM）和热重分析（DTG）鉴定了劣化产物。这项研究的结果表明DEF以两种形式出现。在升高的温度下固化的样品包含DEF I型，导致中等程度的膨胀和损坏。在硫酸盐的存在下，在高温下固化的样品产生Ⅱ型DEF，这对表面造成了明显的破坏并表现出高膨胀性。

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  • 来源
    《Construction and Building Materials》 |2011年第8期|p.3583-3590|共8页
  • 作者

    E. Adamopoulou; P. Pipilikaki; M.S. Katsiotis; M. Chaniotakis; M. Katsioti;

  • 作者单位

    School of Chemical Engineering, Laboratory of Inorganic and Analytical chemistry. National Technical University of Athens, 9 Heroon Polytecniou St. Zografou, Athens 15780, Greece;

    TITAN Cement Co. S.A., Croup R&-D and Quality Department, 18-19200 Eleusina, Greece;

    School of Chemical Engineering, Laboratory of Inorganic and Analytical chemistry. National Technical University of Athens, 9 Heroon Polytecniou St. Zografou, Athens 15780, Greece;

    TITAN Cement Co. S.A., Croup R&-D and Quality Department, 18-19200 Eleusina, Greece;

    School of Chemical Engineering, Laboratory of Inorganic and Analytical chemistry. National Technical University of Athens, 9 Heroon Polytecniou St. Zografou, Athens 15780, Greece;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    def; limestone; sulfates; white cement; mortar;

    机译：def;石灰石;硫酸盐;白水泥;砂浆;

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