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Microscopic Study of Ice Formation and Propagation in Concrete

混凝土中冰形成和传播的微观研究

基本信息

批准号：
9713746
负责人：
Paulo Jose Monteiro
金额：
$ 19.26万
依托单位：
University of California-Berkeley
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
1998
资助国家：
美国
起止时间：
1998-02-15 至 2001-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9713746&HistoricalAwards=false
关键词：
Microscopic Study Ice Formation Propagation

项目摘要

Despite the significant progress research has made in mitigating the damage to portland cement concrete from ice formation and propagation, frost action continues to cause serious damage to structures exposed to the elements. P.I.s plan to use a new microscopic technique using `directional cooling` to undertake a comprehensive research program on ice formation and propagation in concrete and its components. This study will characterize the ice morphology and velocity in various concrete pore solutions, it will establish local concentrations of super-cooled water and it will determine the dynamics of ice propagation in concrete as a function of different amounts of air-entrained voids and deicers. The interaction of ice crystals with the concrete microstructure will be characterized at high magnifications using a new-generation field emission low-temperature scanning microscope, which allows the study of ice formation in small voids. The relationship between the ice formation in concrete and the development of microcracks will be established using a recently developed acoustic emission set-up. The test results will create a link between microstructure and microcracking as affected by cooling rate, presence of deicers, and amount of air entrainment in the matrix. The results of this integrated research program will help the development of the next generation of high-performance concretes to be used in the repair of the aging reinforced concrete infrastructure exposed to cold climate.

尽管在减轻冰的形成和传播对波特兰水泥混凝土的损害方面已经取得了重大进展，但霜冻作用继续对暴露于元素的结构造成严重损害。 P.I.计划使用一种新的显微技术，利用“定向冷却”，对混凝土及其构件中冰的形成和传播进行全面的研究。这项研究将表征冰的形态和速度在各种混凝土孔隙解决方案，它将建立局部浓度的过冷水，它将确定冰在混凝土中的传播作为一个功能的不同数量的空气夹带的空隙和除冰剂的动力学。冰晶与混凝土微观结构的相互作用将使用新一代场发射低温扫描显微镜在高放大倍数下进行表征，该显微镜可以研究小空隙中的冰形成。混凝土中的冰的形成和微裂纹的发展之间的关系将建立使用最近开发的声发射装置。试验结果将建立微观结构和微裂纹之间的联系，受冷却速率、除冰剂的存在和基质中空气夹带量的影响。这项综合研究计划的结果将有助于开发下一代高性能混凝土，用于修复暴露在寒冷气候下的老化钢筋混凝土基础设施。