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首页> 外文期刊>Materials and structures >Decalcification of alkali-activated slag pastes. Effect of the chemical composition of the slag
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Decalcification of alkali-activated slag pastes. Effect of the chemical composition of the slag

机译：碱活化渣浆的脱钙。炉渣化学成分的影响

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摘要

Portland cement decalcification and its effects on paste microstructure and mechanical strength have been widely studied. Decalcification in alkali activated slag (AAS) pastes is still not fully understood, however. The present study therefore explored the process in AAS cement pastes, accelerated by submerging specimens in concentrated ammonium nitrate solutions (NH_4NO_3) for 3-21 days to induce leaching. Two AAS pastes were prepared with slag of different origins (Spanish and Colombian) and chemical compositions. OPC pastes were used as a reference. The findings showed that decalcification has a more adverse impact on OPC than AAS pastes strength. BSEM/EDX and ~(29)Si MAS NMR data nonetheless confirmed that Ca leaches out of C-A-S-H gels (formed in AAS pastes) to an extent that depends on the nature of the prime material. OPC pastes were shown to generate more silica gel with a very low Ca content (Q~3 and Q~4 units). Moreover, the higher the percentage of such units, the lower was mechanical strength. Decalcification in slag with lower MgO and higher Al_2O_3 contents leads to the formation of smaller amounts of silica gel. The resulting gel was more compact and stable due to more intense chain cross-linking a possible tri-dimen-sional structure.
机译：硅酸盐水泥的脱钙及其对糊状组织和机械强度的影响已得到广泛研究。但是，碱活化炉渣（AAS）浆料中的脱钙仍未完全了解。因此，本研究探讨了将AAS水泥浆浸入浓硝酸铵溶液（NH_4NO_3）中3-21天以诱导浸出而加速的过程。制备了两种AAS浆料，其渣料来自不同的来源（西班牙和哥伦比亚），并且具有不同的化学成分。 OPC糊剂用作参考。研究结果表明，脱钙比AAS糊剂强度对OPC的不利影响更大。然而，BSEM / EDX和〜（29）Si MAS NMR数据证实，Ca浸出C-A-S-H凝胶（形成于AAS糊剂中）的程度取决于原始材料的性质。 OPC糊剂显示出可以产生更多的硅胶，且钙含量非常低（Q〜3和Q〜4单位）。此外，这些单元的百分比越高，机械强度越低。 MgO含量较低且Al_2O_3含量较高的炉渣中的脱钙作用导致形成较少量的硅胶。由于更紧密的链交联可能的三维结构，所得凝胶更致密和稳定。

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  • 来源
    《Materials and structures》 |2015年第3期|541-555|共15页
  • 作者

    C. Varga; M. M. Alonso; R. Mejia de Gutierrez; J. Mejia; F. Puertas;

  • 作者单位

    Eduardo Torroja Institute for Construction Science (IETcc-CSIC), Madrid, Spain;

    Eduardo Torroja Institute for Construction Science (IETcc-CSIC), Madrid, Spain;

    School of Materials Engineering, Composite Materials Group (CENM), Universidad del Valle, Santiago de Cali, Colombia;

    School of Materials Engineering, Composite Materials Group (CENM), Universidad del Valle, Santiago de Cali, Colombia;

    Eduardo Torroja Institute for Construction Science (IETcc-CSIC), Madrid, Spain;

  • 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

    Decalcification; Leaching; Alkaliactivated slag (AAS) cements; Mechanical strength; C-A-S-H gel;

    机译：脱钙;浸出碱活性矿渣（AAS）水泥;机械强度;C-A-S-H凝胶;

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