| 摘要: |
| 采用氦流法真密度仪测定了水泥水化过程中水泥浆体的绝对体积变化,并根据水泥浆体绝对体积变化曲线将水泥水化过程划分为极速收缩期、收缩暂停期、快速收缩期和收缩趋缓期4个阶段.结果表明：水泥浆体极速收缩期和快速收缩期发生的绝对体积变化最为明显,且变化幅度较大,其与C3A和C3S的水化密切相关;水泥浆体收缩暂停期的绝对体积通常呈线性规律缓慢减小,但变化幅度较小,其规律与“欠饱和度理论”相符;水泥浆体收缩趋缓期的绝对体积变化曲线通常会出现“膨胀”假象,不能反映水泥浆体绝对体积变化的实际情况,但与水泥浆体孔结构的发展有关,对水泥水化行为的表征仍具有重要的指导意义；水灰比不仅可以影响水泥水化过程,而且可以对水泥浆体各水化阶段的绝对体积变化产生明显影响. |
| 关键词: 氦流法真密度仪 绝对体积变化 水泥 水化过程 |
| DOI：103969/j.issn.1007 9629201904017 |
| 分类号: |
| 基金项目:“十三五”国家重点专项项目(2016YFC0701004); 国家自然科学联合基金资助项目(U1534207);国家自然科学基金资助项目(51678441)；上海市建委课题（沪CXY 2016 012）；上海市联盟计划项目（LM2019047） |
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| Study on Hydration Process of Portland Cement by Helium Pycnometry |
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SUN Zhenping1, ZHANG Chengguang1, YANG Xu1, GE Haosheng1, ETZER Max J2
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1.Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Tongji University, Shanghai 201804, China;2.DuisburgEssen University, Essen 45141, Germany
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| Abstract: |
| The absolute volume change of cement paste in cement hydration process was measured by helium pycnometry. Based on the absolute volume change curve of cement paste, hydration process of Portland cement can be divided into 4 stages, i.e. flash shrinkage stage, shrinkage suspension stage, fast shrinkage stage and shrinkage slowdown stage. Obvious absolute volume change of cement paste occurred in flash shrinkage stage and fast shrinkage stage, and the change ranges were huge, due to the hydration of C3A and C3S. The absolute volume change of cement paste kept decreasing linearly with a very slow rate in shrinkage suspension stage, and its mechanism seems to fit the saturation theory. Differently, there came up “inflation” illusion on the absolute volume change curve of cement paste in shrinkage slowdown stage, and the curve can not reflect the real absolute volume change of cement paste any more. However, this phenomenon was closely related to the development of the pore structure of cement paste, which was important for the characterization of cement hydration behavior. Water cement ratio can affect not only the hydration process of Portland cement, but also the absolute volume change of cement paste in each hydration stage. |
| Key words: helium pycnometry absolute volume change cement hydration process |
