石灰石粉对水泥石抗酸性侵蚀机理的影响研究

Study on influence of limestone powder on acid resistance mechanism of cement paste

采用石灰石粉制备了不同的水泥浆试件,将其浸泡在醋酸和硫酸溶液中,通过强度试验、XRD和SEM等测试方法,观测不同侵蚀时间下水泥浆试件强度和微结构的变化,揭示石灰石粉对水泥石抗酸性侵蚀机制的影响。试验结果表明:在酸性侵蚀条件下,水泥石的强度随水胶比和石灰石粉掺量的增加而降低;在醋酸侵蚀溶液中,主要表现为与氢氧化钙和碳酸钙的反应,侵蚀劣化过程由表及里;在硫酸侵蚀溶液中,硫酸不仅会与氢氧化钙和碳酸钙反应,还会生成石膏,进而可延缓侵蚀进程。

Different cement hardening-slurry pieces containing limestone powder were prepared and soaked respectively in acetic acid solution and sulfuric acid solution. The strength and microstructure of the cement hardening-slurry pieces under different acid attack periods were studied by using strength test, X -ray Diffraction （ XRD ） and scanning electron microscopy （ SEM） techniques, which reveals the effect of limestone powder on acid resistance mechanism of the cement hardening-slurry pieces. The testing results show that the strength of the cement hardening-slurry pieces suffered acid attack decreases with the increase of the water binder ratio and the content of limestone powder. Reactions between calcium hydroxide and calcium carbonate in acetic acid solution make the pastes deteriorate from the exterior to the interior. While in sulfuric acid solution, both calcium hydroxide and calcium carbonate could react with sulfuric acid and gypsum was generated, which can delay the acid attack process.