Why do resistivity measurements in a structure provide useful information on the potential corrosion resistance of reinforced concrete?

Concrete resistivity influences the effectiveness and durability of cathodic protection (CP) of concrete structures. Similarly it is important for electrochemical chloride removal and realkalisation. For a large variation in resistivity within a structure it is more difficult to obtain uniform protection (CP) or a well-predicted result (chloride removal, realkalisation). The resistivity measurement is a useful additional measurement to aid in identifying problem areas or confirming concerns about poor quality concrete. Measurements can only be considered along side other measurements. Reinforcing bars will interfere with resistivity measurements.