废弃混凝土中硬化水泥浆体的再生实验研究_《混凝土与水泥制品》杂志社

摘要：废弃混凝土中的硬化水泥浆体是资源、能源消耗最大、环境负荷最重、经济成本最高的部分，本文研究了硅酸盐脱水相的制备及其相关表征，研究表明，硬化后的水泥浆体在经过煅烧处理后能得到一种名为硅酸盐脱水相的物质，该物质遇水后能再次发生水化反应而得到具有强度的硬化结构体，其中以650℃煅烧温度下得到的硬化水泥浆体脱水相水化后强度最大。同时，还对硅酸盐脱水相-硅微粉系的性能进行了研究，为改善脱水相的强度，加入硅微粉进行了改性，发现加入硅微粉后有强度增加的趋势。

Abstract: The hardened cement paste in waste concrete is the part of the largest energy and resource consumption, the worst environmental impact and the most economic costs. The preparation of silicate dehydration phase and characterization are studied. The results show that a material called silicate dehydration phase can be obtained from the hardened cement paste after calcination, and rehydration hardening structure is obtained by adding silicate dehydration phase substance and water. The biggest rehydration strength of hardened cement paste dehydration phase is derived at 650℃. The research on performance of silicate dehydration phase-silica powder is studied. In order to improve the strength of dehydration phase, the modification for adding silica powder is carried out, the strength is improved after adding microsilica powder.

关键词:

废弃混凝土；脱水相；硅微粉

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（1）硅酸盐硬化水泥浆的脱水相具有再水化的能力，不同煅烧温度的脱水相具有不同的再水化能力，经450℃煅烧后，硬化水泥浆体中的部分水分脱去，很多物质并没有发生分解，但是由于其含有残存的Ca（OH）₂，会使脱水相具有再水化的特性，进而使硅酸盐脱水相具有一定的强度。在所研究的温度段范围内，650℃处理后脱水相水化产物强度可以达到12MPa，这可以做为确定最佳煅烧硬化水泥浆体的温度。在650℃下回收的水泥浆脱水相再水化强度高于在850℃下的水泥浆脱水相抗压强度。实验表明，脱水相再水化产物的强度与其组成、结构及晶型有关，特别是C3S和β-C2S这两种物相有关。

（2）XRD分析表明，硬化水泥浆体在任何脱水温度下逐渐脱水分解，其脱水相是由多种脱水产物组成的。当它们遇水后会进行再水化，重新生成新的钙矾石、C-S-H凝胶、Ca（OH）₂等物质。

（3）硅粉具有较小的粒径和较强的火山灰活性，硅酸盐脱水相的再水化强度均有所提高，金相分析也证明了这一点。

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废弃混凝土中硬化水泥浆体的再生实验研究

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