Understanding the Mechanism and Kinetics of Pyrrhotite-induced Damage in Concrete

了解磁黄铁矿引起混凝土损伤的机制和动力学

• 批准号: 1825386
• 负责人: Aleksandra Radlinska
• 金额: $ 32.47万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1825386&HistoricalAwards=false
• 关键词: Understanding; Mechanism; Kinetics; Pyrrhotite; induced

This research will deliver fundamental knowledge necessary to rapidly and reliably distinguish durable from deleterious aggregates for concrete. Specifically, it will focus on mechanisms and kinetics of pyrrhotite-induced damage in concrete, a situation that has devastated some residential communities in the northern United States. Challenges in identifying and procuring high quality and durable construction aggregate are on the rise, as good quality virgin aggregates are being depleted. Sustainable management of natural resources requires a well-thought-out philosophy of using the remaining supplies. This project will lead to identifying optimal protocols for detection and quantification of pyrrhotite reactivity in concrete. By enabling science-driven selection of the aggregates, the costs of remediating premature deterioration and concrete degradation can be reduced. As such, societal and economic benefits are high and translate into new knowledge and technology to design sustainable built environment. The outcomes of this project will ensure safety, serviceability and continued use of concrete buildings and structures, along with protecting health and financial livelihood of their owners and occupants.The pyrrhotite damage in concrete is a result of deleterious expansions taking place when pyrrhotite (an abundant sulfide mineral in aggregates) oxidizes in contact with moisture and atmospheric oxygen, forming expansive iron hydroxides and sulfuric acid inside concrete. The latter subsequently leads to secondary damages, including acid attack, sulfate attack, and rebar corrosion. To date, pyrrhotite oxidation has been analyzed only in the context of acid mine drainage (low pH). The novelty of this research is in thorough investigation of pyrrhotite oxidation in concrete environment. Specifically, the effects of pH, temperature, RH, and oxygen level on the magnitude and rate of reaction and damage evolution in concrete will be quantified. Selective dissolution of Fe-oxide phases will be conducted and geochemical calculations executed to calculate volumetric changes resulting from pyrrhotite reactivity. Integrated oxygen transport and thermodynamic models will be created for rapid and reliable assessment and prediction of damage. While developed for pyrrhotite-related degradation, this transformative approach will be applicable to a wide array of aggregate-induced damages in concrete.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这项研究将提供必要的基础知识，以快速可靠地区分混凝土的耐久骨料和有害骨料。具体地说，它将专注于磁黄铁矿导致混凝土破坏的机制和动力学，这种情况已经摧毁了美国北部的一些居民区。由于高质量的原始骨料正在耗尽，在确定和采购高质量和耐用建筑骨料方面的挑战正在增加。自然资源的可持续管理需要一个深思熟虑的使用剩余供应的哲学。该项目将导致确定检测和量化混凝土中磁黄铁矿活性的最佳方案。通过实现科学驱动的骨料选择，可以降低补救过早退化和混凝土退化的成本。因此，社会和经济效益很高，并转化为新的知识和技术，以设计可持续的建筑环境。该项目的成果将确保混凝土建筑物和构筑物的安全、适用性和持续使用，并保护其所有者和居住者的健康和经济生活。混凝土中的磁黄铁矿损坏是磁黄铁矿(集料中丰富的硫化物矿物)在与水分和大气氧气接触时发生有害膨胀的结果，在混凝土中形成膨胀的氢氧化铁和硫酸。后者随后导致二次破坏，包括酸侵蚀、硫酸盐侵蚀和钢筋腐蚀。到目前为止，磁黄铁矿氧化只在酸性矿山废水(低pH值)的背景下进行分析。本研究的创新之处在于对磁黄铁矿在具体环境中的氧化进行了深入的研究。具体地说，将量化pH、温度、相对湿度和氧气水平对混凝土中反应和损伤演化的大小和速度的影响。将进行铁氧化物相的选择性溶解，并进行地球化学计算，以计算磁黄铁矿反应性引起的体积变化。将建立综合的氧气传输和热力学模型，以快速可靠地评估和预测损害。虽然这种变革性的方法是为与磁黄铁矿相关的退化而开发的，但它将适用于大量混凝土聚集体诱导的损害。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

On the performance-based approaches to evaluate the oxidation potential of iron sulfide-bearing aggregates in concrete

基于性能的方法评估混凝土中含硫化铁骨料的氧化电位

• DOI: 10.1016/j.cement.2023.100059
• 发表时间: 2023
• 期刊: CEMENT
• 作者: Li, Zhanzhao;Kaladharan, Gopakumar;Bentivegna, Anthony;Radlińska, Aleksandra
• 通讯作者: Radlińska, Aleksandra