Kirchheim A P, Fernàndez-Altable V, Monteiro P J M, Dal Molin D C C, Casanova I
Department of Civil Engineering, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
Department of Civil and Environmental Engineering, University of California, Berkeley, CA USA.
J Mater Sci. 2009;44(8):2038-2045. doi: 10.1007/s10853-009-3292-3. Epub 2009 Apr 1.
Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to study the microstructural changes and phase development that take place during the hydration of cubic (pure) and orthorhombic (Na-doped) tricalcium aluminate (CA) and gypsum in the absence and presence of lime. The results demonstrate that important differences occur in the hydration of each CA polymorph and gypsum when no lime is added; orthorhombic CA reacts faster with gypsum than the cubic phase, forming longer ettringite needles; however, the presence of lime slows down the formation of ettringite in the orthorhombic sample. Additional rheometric tests showed the possible effects on the setting time in these cementitious mixes.
场发射扫描电子显微镜（FE-SEM）和X射线衍射（XRD）已被用于研究在有无石灰存在的情况下，立方（纯）和正交（钠掺杂）铝酸三钙（CA）与石膏水化过程中发生的微观结构变化和相发展。结果表明，在不添加石灰时，每种CA多晶型物与石膏的水化过程存在重要差异；正交CA与石膏的反应比立方相更快，形成更长的钙矾石针状晶体；然而，石灰的存在减缓了正交样品中钙矾石的形成。额外的流变测试显示了这些水泥混合料对凝结时间可能产生的影响。
