混凝土凝结过程中水分变化规律研究

发布时间：2018-05-04 03:02

本文选题：水工混凝土 + 低场核磁共振　；参考：《水力发电学报》2017年07期

【摘要】：分层浇筑混凝土层间性能与下层新拌合混凝土凝结过程中的水分状态息息相关,因此本研究主要探究水分变化规律及机理以指导层间混凝土施工。研究采用低场核磁共振技术,并进行相应开发,对不同组成成分、不同水灰比新拌混凝土试样在环境影响下的水分含量及分布进行测试。研究结果表明:凝结过程中水分变化主要由水化耗水、蒸发失水和内部水分迁移三部分组成,在这几种作用的影响下,凝结过程中水分含量及分布随着环境的变化而呈现出相应的规律,表层尤为突出。通过对内部水分迁移的机理及规律进一步研究,研究发现混凝土凝结前期水分迁移主要是密度差异导致的近似层流运动,而凝结后期主要是水分含量梯度导致的扩散运动。研究结果可对分层浇筑混凝土施工提供相应的参考价值。
[Abstract]:The interlayer performance of layered concrete is closely related to the moisture state in the condensation process of the new mixing concrete. Therefore, this study mainly explores the law and mechanism of water change in order to guide the construction of interlayer concrete. The low field NMR technique was used to test the moisture content and distribution of fresh concrete samples with different composition and water / cement ratio under the influence of environment. The results show that the water change in the condensation process is mainly composed of three parts: hydration water consumption, evaporation water loss and internal water migration. The water content and distribution in the condensation process show the corresponding law with the change of environment, especially in the surface layer. Through the further study on the mechanism and law of internal water migration, it is found that the water migration in the early stage of concrete condensation is mainly caused by the approximate laminar flow movement caused by the difference in density, while in the late stage of condensation it is mainly caused by the diffusion movement caused by the gradient of water content. The results can provide reference value for layered concrete construction.
【作者单位】：清华大学水沙科学与水利水电工程国家重点实验室;
【基金】：国家重点基础研究发展计划(973计划)(2013CB035902) 国家自然科学基金(51279087) 水沙科学与水利水电工程国家重点实验室科研课题(2015-KY-04)
【分类号】：TV431

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