石膏对石灰石粉水泥基材料水化及硬化性能的影响

发布时间：2018-02-10 15:48

本文关键词： 石灰石粉石膏胶凝材料水化硬化体微结构　出处：《材料导报》2017年04期 　论文类型：期刊论文

【摘要】：针对我国目前非荷载作用下混凝土严重开裂的问题,以"比表面积较低的水泥熟料-比表面积较高的掺合料-足够掺量的石膏"构成的胶凝材料体系为研究对象,通过水化热速率、X射线衍射(XRD)、扫描电子显微镜(SEM)、压汞法(MIP)及热重-差示扫描量热法(TG-DSC)等手段,研究石膏对石灰石粉水泥基材料水化及硬化体微结构的影响。结果表明,石灰石粉能够加速C3A与石膏作用生成钙矾石相,在足量石膏存在的条件下,能够阻碍钙矾石向低硫型硫铝酸钙转变;石灰石粉的掺入与石膏一起延缓了C3A的水化;在石灰石粉和足够石膏同时存在的情况下,C3A水化生成具有膨胀性的水化碳铝酸钙和高硫型硫铝酸钙,补偿了收缩,提高了水泥基材料的抗裂性能;熟料粗磨、掺合料细磨及较高石膏掺量的胶凝材料体系配制的C30和C50等级混凝土,强度能持续增大,从28d到180d,强度分别提高了36.7%和33.3%,混凝土结构紧密、孔隙率低、有害孔含量少。
[Abstract]:In order to solve the problem of serious cracking of concrete under non-load in our country, the cementing material system composed of "cement clinker with low specific surface area, admixture with high specific surface area and sufficient amount of gypsum" is taken as the research object. The effects of gypsum on the hydration and hardening microstructure of limestone cement based materials were studied by means of X-ray diffraction of hydration heat rate, scanning electron microscope (SEM), mercury injection (MIP) and thermogravimetric differential scanning calorimetry (TG-DSC). Limestone powder can accelerate the interaction between C3A and gypsum to form ettringite phase, which can hinder the transformation of ettringite to low-sulfur calcium sulphoaluminate under the condition of sufficient gypsum, and the incorporation of limestone powder and gypsum can delay the hydration of C3A. In the presence of limestone powder and enough gypsum at the same time, C3A hydrates to form expansive calcium carbonate hydrate and high sulfur calcium sulphoaluminate, which compensates shrinkage and improves the crack resistance of cement-based materials. The strength of C _ (30) and C _ (50) grade concrete prepared by fine grinding and high gypsum cementitious material system increases continuously, from 28 days to 180 days, the strength increases by 36.7% and 33.3 respectively. The concrete structure is compact, the porosity is low, and the harmful pore content is less.
【作者单位】：北京科技大学土木与环境工程学院;北京建筑大学土木与交通工程学院;
【基金】：国家自然科学基金(51578039)
【分类号】：TU528

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