This project intends to develop a sensor system that allows in-situ measurement of concretes pore solution resistivity, to supplement existing procedures for durability assessment. The innovation includes one or more sensors that are embedded inside concrete and a mobile measuring device to interrogate the sensor.Phase I project will explore candidate body materials for the sensor, manufacturing techniques, optimum sensor geometry/packaging, and the best methods for reading/measuring the sensor output. Phase I will also explore the costs, material availability, manufacturability, scale-up, marketability, technology transfer, and industry implementation of the proposed sensor system. Phase I output is a proof-of-concept report summarizing the above and offering one or more best prototype designs to be produced and tested in Phase II. The report will offer Phase II plans and estimated timeline for the prototype(s) production, accuracy verification, and evaluation by FHWA and State highway agencies. The report will discuss opportunities and obstacles to implementation of the technology.The project team includes Callentis Consulting Group with extensive experience in analysis and simulation of porous media, electrochemistry measurement techniques and pavement engineering, and Penn State University which brings expertise in cementitious materials, electrical property measurements and sensing of concrete, and materials science and polymer engineering.