MEASUREMENTS OF STEEL POTENTIAL FOR CONTROLLING CORROSION OF REINFORCEMENT

This paper presents the results of laboratory tests the object of which was to ascertain the applicability of direct, long term measurements of electrochemical potential and anodic current using simple electrodes as a means to predict or continuously control the state, as well as the rate of corrosion, of reinforcing steel in concrete. The tests included concrete specimens made of two different kinds of cement (Portland and high furnace) with different amounts of chlorides added to the mixtures which had been cured at laboratory conditions (20 degrees C, 80% relative humidity). The tests themselves took place in a solution of saturated Calcium Hydroxide Ca(OH)2 + 3% Cl- at 20 degrees C, the reference electrode being kept in a different vessel. Well-known electrochemical half- cells as well as simple rods of special stainless steel were used for reference. Thus, the tests may give some answer to the influence of the type of cement, the appearance of chlorides in the boundary layer steel/concrete, the type of reference electrode and the testing time - each on the suitability of this measuring technique. (A) For the covering abstract of the conference see IRRD 858602.