Concrete Durability: Linking Material Properties and Field Performance

混凝土耐久性：将材料特性与现场性能联系起来

• 批准号: RGPIN-2016-04873
• 负责人: Thomas, Michael
• 金额: $ 2.26万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615352
• 关键词: Concrete; Durability; Linking; Material; Properties

Concrete is the most widely-used construction material in the world but is often poorly understood and inadequately designed leading to premature deterioration in many aggressive exposure conditions. The applicant's research program is aimed at developing a fundamental understanding of the deterioration processes that can occur in different environments, determining the appropriate material properties to resist the destructive forces, quantifying and predicting rates of deterioration, and validating experimental observations with field performance studies. The main focus of the ongoing research program is to continue the development and improvement of appropriate test methods and predictive models for evaluating concrete's resistance to some of the more prevalent forms of deterioration; these are: (i) chloride ingress and corrosion of steel, (ii) alkali-silica reaction, (iii) sulfate attack, and (iv) combined ASR and freeze-thaw. The main objectives of the research program are: 1. Validation of existing models for predicting chloride penetration, including models developed by the applicant and various collaborators. Validation will be conducted through ongoing long-term laboratory and field-exposure testing, and sampling of structures. A two-phase model will be developed to include the impact of carbonation as it penetrates from the surface. 2. Development of improved test methods for alkali-silica reaction (ASR) with exposure conditions designed to provide sufficient moisture without allowing the ingress or egress of alkalis from the concrete. Validation and calibration will be performed using data from numerous long-term exposure sites that have been established by the applicant and collaborators, and through the use of data from existing structures that have been monitored for decades. 3. Synergy between ASR and freeze-thaw attack. ASR results in expansion and cracking of concrete which may not in itself result in the end of the life of a structure but which may render it more vulnerable to other processes. Concretes with a range of ASR-damage levels and various degrees of saturation will be exposed to freeze-thaw cycles. This component of the research program (ASR-freeze/thaw) will conducted in collaboration with Jason Weiss of Oregon State University (previously with Purdue University). 4. Development of an improved test for evaluating sulfate resistance of concrete. The test will be benchmarked using data from a sulfate exposure site.

混凝土是世界上使用最广泛的建筑材料，但往往是不了解和设计不当，导致过早恶化，在许多积极的暴露条件。申请人的研究计划旨在对不同环境中可能发生的劣化过程进行基本了解，确定适当的材料特性以抵抗破坏力，量化和预测劣化速率，并通过现场性能研究验证实验观察结果。正在进行的研究计划的主要重点是继续开发和改进适当的测试方法和预测模型，以评估混凝土对一些更普遍的劣化形式的抵抗力;这些劣化形式是：（i）氯化物侵入和钢筋腐蚀，（ii）碱-硅反应，（iii）硫酸盐侵蚀，以及（iv）ASR和冻融相结合。该研究计划的主要目标是： 1.验证用于预测氯化物渗透的现有模型，包括由申请人和各种合作者开发的模型。将通过持续的长期实验室和现场暴露测试以及结构取样进行验证。将开发一个两相模型，以包括碳酸化从地表渗透的影响。 2.开发改进的碱-硅反应（ASR）试验方法，暴露条件旨在提供足够的水分，而不允许碱从混凝土中进出。验证和校准将使用申请人和合作者建立的许多长期接触地点的数据，并通过使用已监测数十年的现有结构的数据进行。 3. ASR和冻融侵蚀之间的协同作用。ASR导致混凝土的膨胀和开裂，其本身可能不会导致结构寿命的终止，但可能使其更容易受到其他过程的影响。具有一系列ASR损伤水平和各种饱和度的混凝土将暴露于冻融循环。这项研究计划的组成部分（ASR冷冻/解冻）将与俄勒冈州州立大学的Jason韦斯（以前与普渡大学合作）合作进行。 4.改进的混凝土抗硫酸盐侵蚀性试验方法的研究。将使用硫酸盐暴露部位的数据对测试进行基准测试。