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Fiber Optics for Evaluation of Pavement Reinforcement Materials in Resisting Reflection Cracking

A major maintenance problem of pavement is the reflection cracking of pavement overlays at the location of joints and cracks in the underlayers. Pavement reinforcement materials (PRM) are used to reinforce the asphalt concrete (AC) overlay to delay reflection cracking. Assessing the effectiveness of PRM in limiting reflection cracking can be achieved by direct measurement of strain distribution within the PRM and AC overlay. A fiber-optic sensor is the only alternative that is compatible with the fiberglass structure of the PRM used in this study and, therefore, is used to measure strain within the PRM. A program of investigation, developed at the Institute for Research in Construction of the National Research Council Canada, aims at studying the state of stress leading to joint opening in pavement layers and assessing the effectiveness of PRM in reducing such cracks through monitoring the performance of PRM using embedded fiber-optic strain sensors. The investigation involves both laboratory testing and long-term field monitoring of instrumented road section. The instrumentation aspect of the laboratory evaluation of PRM effectiveness using embedded fiber-optic sensors is described. An instrumentation procedure is developed that includes sensor mounting and embedding, mechanical protection, calibration, and data acquisition system. The performance of the developed monitoring system in asphalt concrete pavement specimens is assessed in controlled laboratory conditions.