Improving ground penetrating radar evaluation of corrosion in reinforced concrete bridge decks

这项发现基金提案支持达尔豪斯大学的一项民用基础设施无损评估（NDE）的长期研究项目，该项目通过扩展评估探地雷达（GPR）数据的技术，从暴露的表面（未铺砌的）钢筋混凝土甲板到更复杂的沥青铺砌甲板。钢筋混凝土桥面往往是最难以准确诊断腐蚀损伤的因素之一，特别是当沥青混凝土磨损面存在时。拟议的研究将扩展我们对多层路面系统（桥面）及其不同程度的损坏和氯化物污染如何影响探地雷达信号传播的基本理解。具体而言，研究将集中在两个方面：建模和量化由沥青混凝土状况和厚度引起的信号衰减；研究了覆盖层内不同氯离子浓度分布对预测腐蚀损伤信号损失阈值的影响。将申请人目前评估未铺装钢筋混凝土桥面的方法成功地应用于更常见和更复杂的沥青铺装桥面的恶化情况，将极大地提高准确性和可靠性，从而可以在网络层面上对腐蚀引起的损坏的修复进行评估和优先排序。对当今工业中使用的各种普通和高性能混凝土混合物的现象进行建模和校准，将其应用范围扩展到更广泛的服务材料中。沥青混凝土状况的评价能力也将对公路路面系统的评价产生重大影响。通过拟议的研究，将培养一名博士和两名应用科学硕士学生，培养两名精通基础设施探地雷达调查的咨询工程师和一名将继续推进该领域研究的学术研究员。通过与国际同行、本地行业的合作，以及在相关国际会议上的研究报告，学生将获得强大的研究技能和行业经验的基础。

This Discovery grant proposal supports a long term research program at Dalhousie University in Non-Destructive Evaluation (NDE) of civil infrastructure by extending techniques for evaluating Ground Penetrating Radar (GPR) data from exposed surface (unpaved) reinforced concrete decks to the more complicated case of asphalt paved decks. Reinforced concrete bridge decks tend to be one of the most problematic elements to accurately diagnose corrosion damage, particularly when asphalt concrete wearing surfaces are present. The proposed research will extend our fundamental understanding of how GPR signal propagation is affected through multilayered pavement systems (bridge decks) and their various degrees of damage and chloride contamination. Specifically, the research will focus on two areas: modeling and quantifying signal attenuation resulting from the condition and thickness of the asphalt concrete; and, the effect of different chloride concentration profiles within the cover layer on the signal loss threshold used to predict corrosion damage. Successful adaptation of the applicant's current approach for evaluating unpaved reinforced concrete bridge decks to the more common and complex case of deteriorated asphalt-paved decks will greatly improve the accuracy and reliability by which repairs of corrosion-induced damage can be estimated and prioritized on a network level. Modeling and calibrating the phenomena over a broad range of normal and high performance concrete mixtures used in industry today will extend its application to a broader range of materials used in service. The ability to evaluate the condition of the asphalt concrete will also have significant impact in highway pavement systems evaluation. One Ph.D. and two Master of Applied Science students will be trained through the proposed research, developing two consulting engineers who are skilled in GPR investigations of infrastructure and one academic researcher who will continue to advance research in this field. The students will gain a foundation of strong research skills and industrial experience through collaboration with international colleagues, local industry, and research presentations at relevant international conferences.