Corrosion monitoring in reinforced concrete structures with an innovative rf-based sensor

The research-project carried out at the Institute for Building Materials, Concrete Construction and Fire Protection (iBMB) at Technische Universitht Braunschweig, Germany and at HertzSystemtechnik, Germany focuses on the development of a wireless measurement system for corrosion monitoring. The measurement system detects the initiation of corrosion of reinforcement. The main goal is to develop a small and robust sensor that can be integrated into the cover-layer of reinforced concrete. Due to the chosen geometry of the sensor it is possible to detect the progress of the depassivation-front in staggered intervals of depth Ie. g. carbonation/critical chloride concentrationI. The sensor can be applied to new-built and existing structures. There is a vast field of applications concerning new-built and existing structures such as car parks and bridges. Therefore the development of the sensor is high in demand to the national economy. For the subsequent installation of the sensor it is necessary to carry out a core drilling to place the sensor in the final location. Afterwards it is indispensable to bind the sensor physically with the help of a grouting mortar to the perimeter of the drilling hole. Especially, the properties of the grouting mortar are extremely relevant since it is supposed to bridge the gap between the sensor and perimeter of the bore hole. In this context it needs to be considered that there might be voids in the grouting mortar which falsify the transport of harmful substances and consequently bias the measurement result. In order to prevent from this error it is necessary to provide methods to check on voids in-situ. Finally, the application of the sensor in an existing structure is presented.