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

本发现奖助金提案支持达尔豪西大学的一项长期研究计划，通过将用于评估地面穿透雷达（GPR）数据的技术从暴露表面（未铺装）钢筋混凝土桥面扩展到沥青铺装桥面的更复杂情况，对民用基础设施进行无损评估（NDE）。 钢筋混凝土桥面往往是最有问题的元素之一，以准确诊断腐蚀损坏，特别是当沥青混凝土磨损表面存在。拟议的研究将扩大我们的基本理解如何通过多层路面系统（桥面）和他们的不同程度的损害和氯化物污染的影响GPR信号传播。 具体而言，研究将集中在两个领域：建模和量化信号衰减的条件和厚度的沥青混凝土;和，不同的氯离子浓度分布覆盖层内的信号损失阈值的影响，用于预测腐蚀损坏。 申请人目前评估未铺装钢筋混凝土桥面的方法成功地适用于更常见和复杂的沥青铺装桥面恶化的情况，将大大提高准确性和可靠性，通过这种方法，可以在网络级别上估计和优先考虑腐蚀引起的损坏的修复。 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，将其应用扩展到更广泛的服务材料。 对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。 一个博士和两名应用科学硕士学生将通过拟议的研究进行培训，培养两名擅长基础设施GPR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。 学生将通过与国际同事，当地行业的合作以及在相关国际会议上的研究报告获得强大的研究技能和工业经验的基础。

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.