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

这项发现拨款提案支持达尔豪西大学的一项长期研究计划，通过将评估探地雷达(GPR)数据的技术从裸露的表面(未铺设)的钢筋混凝土甲板扩展到更复杂的沥青铺装甲板，从而支持民用基础设施的无损评估(NDE)。钢筋混凝土桥面往往是准确诊断腐蚀损伤的最有问题的元素之一，特别是当沥青混凝土存在磨损表面时。拟议的研究将扩大我们对探地雷达信号传播如何通过多层路面系统(桥面)及其不同程度的损坏和氯离子污染的基本理解。具体地说，研究将集中在两个领域：模拟和量化由沥青混凝土的状况和厚度引起的信号衰减；以及覆盖层内不同的氯浓度分布对用于预测腐蚀损伤的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调整到更常见和更复杂的沥青铺装桥面破损的情况，将极大地提高准确性和可靠性，从而可以在网络一级估计腐蚀引起的损坏的修复并确定其优先次序。对当今工业中使用的各种普通和高性能混凝土混合料进行建模和校准，将把它的应用扩展到更广泛的服务材料范围。评价沥青混凝土状况的能力也将对公路路面系统的评价产生重大影响。一名博士和两名应用科学硕士学生将通过拟议的研究接受培训，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学术研究人员，他们将继续推进这一领域的研究。学生将通过与国际同行、当地行业和在相关国际会议上的研究报告合作，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.