This sensor for existing structures measures the most important parameters for assessing the corrosion risk of the reinforcement. It consists of a segmented stainless steel tube for moisture measurement, 2 reinforcing steel sensors for corrosion current measurements and 2 PT 1000 temperature elements. The sensor is placed in a Ø 22 mm borehole and the narrow annular gap is pressed with a special mortar. The thin layer of mortar takes up the surrounding conditions of the concrete quickly (experience value approx. 2 weeks). By measuring the electrical concrete resistance (impedance measurement at 1 kHz) between the segment and the surrounding reinforcement, the specific concrete resistance (reciprocal value of the conductivity) can be calculated taking into account the cell constant. With the help of the measured concrete temperatures a temperature compensation of the concrete resistances can be carried out. The corrosion current (macro element current) to the surrounding passive reinforcement is measured with the two reinforcing steel sensors. This current can be converted directly into an ablation current. [Data sheets]

This sensor, which is an early warning system for corrosion, measures the progress of the front of the critical chloride content for triggering pitting. The sensor consists of 4 normal concrete steels, which sit at a certain distance (variable concrete cover) from the sensor beam. The sensor with the 4 reinforcing steels is attached to the existing reinforcement by means of a special, movable bracket. The first 2 to 3 reinforcing steel sensors are located in front of the first reinforcement layer. At the same time, this bracket ensures the connection to the general reinforcement. The corrosion current (macro element current) between the reinforcing steel sensor and the surrounding reinforcement is monitored. When the corrosion is activated (initiated), the corrosion current increases exponentially, which is due to the triggering of pitting corrosion. Since the chloride front has not yet reached the static reinforcement, measures can be taken to slow down or stop further chloride input. Instead of the corrosion current, the potential of the reinforcing steel can also be measured. However, for this purpose a suitable reference electrode must be embedded in concrete.  [Data sheets]

This sensor is used to monitor the moisture equilibriurm in concrete and can, for example, be used to monitor the effectiveness of a surface protection system (hydrophobization or coating).

The sensor consists of 4 regularly spaced thin stainless steel rods and 2 Pt1000 temperature measurement points. It is used analogous to the CS-040 sensor attached to the reinforcement. By measuring the electrical resistance of the concrete (impedance measurement at 1 kHz) between the sensor rods and the reinforcement and taking the cell constant into account, the specific concrete resistance (resistivity) can be determined at the respective rod depths. The measured concrete temperature allows for a temperature compensation of the impedance values.

The concrete resistivity correlates inversely to the moisture content. Using an appropriate calibration curve, the concrete moisture profile can be found.