SGER: An Exploratory Study of a Test Device for Concrete Permeability

SGER：混凝土渗透率测试装置的探索性研究

• 批准号: 0243451
• 负责人: Paul Zia
• 金额: $ 6万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-03-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0243451&HistoricalAwards=false
• 关键词: SGER; Exploratory; Study; Test; Device

Concrete is the most widely used material for the civil infrastructure.Deterioration of concrete is a major worldwide problem. An important factor thataffects the durability of concrete structure is the permeability of concrete. Lowpermeability reduces the entry of moisture and aggressive substances into concrete, thus provides better protection for the steel reinforcement and limits deterioration of concrete due to freezing-thawing. However, for lack of a suitable test method and device, the permeability of concrete is not routinely measured as a means of quality assessment and control.In a recent study, the PI and his co-worker conceived an innovative method tomeasure concrete permeability by using a simple and economical test device. The method makes use of an axi-symmetric surface air flow model to determine the concrete permeability index. Their work provided the proof of the concept and demonstrated that the test device was capable of making consistent measurements for concrete with different water-cement ratios at different ages. They also verified that air flow within one-half inch from the concrete surface was achievable. In addition, they found satisfactory correlations between the permeability index with the results of rapid chloride permeability tests and chloride penetrations from 90-day ponding tests.The objectives of this exploratory research are to further develop and refine thetest method and device. More specifically, the research will address four critical issues: (1) determine the effect of the moisture content of concrete on permeability, (2) explore techniques to dry the concrete surface to a sufficient depth to eliminate the effect of moisture content, (3) improve the test device so as to increase the depth of air flow into the concrete, and (4) establish an appropriate procedure for the concrete surface preparation in the field so that the test device can be applied successfully

混凝土是民用基础设施中应用最广泛的材料，混凝土的劣化是一个世界性的重大问题。影响混凝土结构耐久性的一个重要因素是混凝土的渗透性。低渗透性减少了水分和侵蚀性物质进入混凝土，从而为钢筋提供更好的保护，并限制了混凝土因冻融而劣化。然而，由于缺乏合适的测试方法和设备，混凝土的渗透性并没有常规地作为质量评估和控制的手段来测量。在最近的一项研究中，PI和他的同事构思了一种创新的方法，通过使用简单而经济的测试设备来测量混凝土的渗透性。该方法利用轴对称表面空气流动模型来确定混凝土的渗透性指标。他们的工作证明了这一概念，并证明了该测试设备能够在不同年龄对不同水灰比的混凝土进行一致的测量。他们还证实，空气流动在半英寸从混凝土表面是可以实现的。此外，他们发现渗透指数与快速氯离子渗透试验结果和90天积水试验的氯离子渗透率之间存在令人满意的相关性。更具体地说，研究将解决四个关键问题：（1）确定混凝土含水量对渗透性的影响，（2）探索将混凝土表面干燥到足够深度以消除含水量影响的技术，（3）改进测试装置以增加空气流入混凝土的深度，建立了现场混凝土表面处理的程序，使试验装置能够成功应用