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用X射线衍射、Fourier变换红外光谱、扫描电子显微镜和X射线能量色散谱等方法研究了浸泡在pH值为2的模拟酸雨中硅酸盐水泥石物相组成的变化。结果表明:硬化水泥浆体的破坏主要是酸雨中H+与SO42-共同作用的结果。一方面,H+使硬化水泥石中的Ca(OH)2,水化硅酸钙(C-S-H)凝胶,xCaO.Al2O3.yH2O(CxAHy)等物质发生分解、转化,而引起结构溃散性腐蚀;另一方面,SO24-与水泥石作用,生成膨胀性的物质CaSO4.2H2O,而引起膨胀性腐蚀。在酸雨持续作用下,水泥石由表及里逐渐遭到侵蚀破坏,直至完全溃散,最终转变成由石膏、硅胶和铝胶等组成的一种白色稀泥状混合物。
The changes of the phase compositions of Portland cement in simulated acid rain at pH 2 were studied by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray energy dispersive spectroscopy. The results show that the destruction of hardened cement paste is mainly caused by the interaction of H + and SO42- in acid rain. On the one hand, H + decomposes and converts Ca (OH) 2, CSH gel and xCaO.Al2O3.yH2O (CxAHy) in hardened cement, causing structural corrosion; On the one hand, SO24- works with cement stones to produce an expansible material, CaSO4.2H2O, which causes swelling corrosion. Under the continuous action of acid rain, the cement stone is gradually eroded from the surface to the surface and completely disintegrated, finally turning into a white, squealing mixture composed of gypsum, silica gel and aluminum glue.