Potential monitoring system for corrosion of steel in concrete

Corrosion of steel in concrete reduces the life and durability of concrete structures. It is a worldwide problem, which causes heavy losses to the economy and industry. The corrosion of steel is inevitable. The durability of concrete structures primarily depends on the condition of the embedded steel in concrete, apart from any deterioration that the concrete may undergo. To determine the condition of the embedded steel, potential surveys are carried out on concrete structures and this is one of the most important monitoring techniques. Most of these measurements in the field are manually carried out and the data obtained are analyzed. Automation is the best solution where repeated measurements have to be made. This eliminates the human errors in the measurement and improves the accuracy of the data measured from humanly inaccessible regions of a structure. With the advent of computer-based I/O cards and faster chips for data processing, the measurement of data such as voltage, current, etc. from a large number of points simultaneously is possible. In the present work, simultaneous measurement of potential of steel from different points in a concrete slab, using NI-DAQ card (AT-MIO-16E-10), has been made. Suitable software was developed for interpreting the measured data based on ASTM C-876, to assess the condition of the embedded steel. More number of data was acquired in each channel and averaged as the data acquisition device can acquire 100 kS/s. Software was developed using Visual Basic 6.0 and NI-DAQ driver software. Data acquisition system developed is a user-friendly one.