Identification of Reactive Aggregates Using Neutron Diffraction and Development of Methods to Reduce the Alkali-silica Reaction Expansion

利用中子衍射识别反应聚集体并开发减少碱硅反应膨胀的方法

• 批准号: 0624764
• 负责人: Paulo Jose Monteiro
• 金额: $ 22万
• 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: 2006
• 资助国家: 美国
• 起止时间: 2006-10-01 至 2010-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0624764&HistoricalAwards=false
• 关键词: Identification; Reactive; Aggregates; Using; Neutron

Abstract The alkali-silica reaction (ASR) involves reactive siliceous aggregates and highly alkaline concrete pore solution producing an expansive alkalisilicate gel, which can imbibe water and then expand. Many dams, reinforced concrete bridges, and pavements require continuous repair or replacement because of cracks caused by this deleterious reaction. Concrete deterioration caused by the ASR has been investigated for many years, however, an understanding of the mechanisms underlying this expansion is still limited. The objective of this proposal is to establish a holistic study of the rocks that causes ASR and then develop chemical admixtures that reduce this expansion. The investigation will be done at various scales, from the molecular to the engineering level. The theoretical model will be validated through rigorous experimental research to quantitatively characterize rock aggregates, their microstructure, and the resulting gel. An important technique to study the bulk deformation properties of mineral components in rocks will be the time-of-flight neutron diffraction facilities at Los Alamos National Laboratory. We will also perform chemical and physical tests on these rocks and on concrete samples to establish a comprehensive and reliable methodology to identify reactive rocks for concrete structures. New chemical admixtures will be studied to reduce or eliminate the expansion in concrete. The results of this research will provide critical information for the aggregate and concrete science and industry.

摘要碱-硅酸反应(ASR)涉及活性硅质骨料和高碱性混凝土孔隙溶液，生成可膨胀的碱硅酸盐凝胶，该凝胶可以吸水然后膨胀。由于这种有害反应造成的裂缝，许多大坝、钢筋混凝土桥梁和人行道需要持续维修或更换。多年来，人们对ASR引起的混凝土劣化进行了调查，然而，对这种膨胀背后的机理的了解仍然有限。这项建议的目标是对导致ASR的岩石进行全面研究，然后开发减少这种膨胀的化学混合物。这项研究将在不同的尺度上进行，从分子到工程水平。理论模型将通过严格的实验研究进行验证，以定量表征岩石集合体、其微观结构和生成的凝胶。洛斯阿拉莫斯国家实验室的飞行时间中子衍射设备将是研究岩石中矿物组分整体变形特性的一项重要技术。我们也会对这些岩石和混凝土样本进行化学和物理测试，以建立一套全面和可靠的方法来识别混凝土结构中的活性岩石。将研究新的化学外加剂以减少或消除混凝土中的膨胀。这项研究的结果将为骨料和混凝土科学和工业提供关键信息。