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采用流化床—气相沉积法,将Na OH、Na2SO4等改性材料溶液雾化、沉积于粉煤灰颗粒表面。采用扫描电子显微镜(SEM)及傅里叶变换红外光谱仪(FTIR)分析了改性材料结晶特征及对粉煤灰的溶蚀机理,测试并分析了改性粉煤灰—水泥净浆、砂浆强度发展,并通过SEM、X射线衍射(XRD)研究了水泥净浆水化进程。结果表明,Na OH可以与粉煤灰发生溶蚀反应,使其中的Si-O键断裂,水化活性提高。Na2SO4在粉煤灰表面晶粒尺寸更小、分布更均匀,并在水化过程中存留在粉煤灰表面,促进粉煤灰及其附近水泥熟料的水化。两种作用均可提高粉煤灰颗粒与水泥基体的锚固作用,促进强度发展。当改性材料掺量分别为0.23%和1.17%时,水泥净浆、砂浆强度均高于传统的化学激发法。
The fluidized bed - vapor deposition method, Na OH, Na2SO4 and other modified material solution atomized, deposited on the fly ash particle surface. The crystallization characteristics and dissolution mechanism of fly ash were analyzed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The strength of the modified fly ash-cement paste was tested and analyzed. The hydration process of cement paste was studied by SEM and X-ray diffraction (XRD). The results show that Na OH can dissolve with fly ash, causing the Si-O bond to break and the hydration activity to increase. Na2SO4 in the fly ash surface grain size smaller, more evenly distributed, and remained in the hydration process of fly ash surface, to promote the hydration of fly ash and cement clinker nearby. Both of these effects can improve the anchoring effect between fly ash particles and cement matrix and promote the development of strength. When the content of modified materials were 0.23% and 1.17% respectively, the strength of cement paste and mortar were higher than the traditional chemical excitation method.