Examination of the influence of tensile stress on corrosion rate of reinforcing steel covered with polymeric sulphuric coating
Mariusz Książek Wrocław University of Technology, Faculty of Composite and Special Material Technology, Grunwaldzki 11, 50-377 Wrocław, Poland
Quarterly No. 4, 2008 pages 349-353
DOI:
keywords: corrosion, reinforcing steel, tensile stress, polymeric sulphuric coating, polarization, corrosion, reinforcing steel
abstract In paper presents investigation results of corrosion rate for steel reinforcement bars that have been covered with polymer coating and have been exposed to tensile stresses in a solution simulating pore-liquid of concrete. Experimental investigation of tendencies that occur during corrosion process of reinforcing steel covered with polymer and exposed to tensile stress has been attempted. To determine an effect of tensile stress on corrosion rate for St3S-b steel that has been covered with sulphuric coating and exposed to aqueous environment that was to simulate pore-liquid of concrete contaminated with chloride ions was an aim of the investigation. The samples underwent loading in an one-axial state of the stress including varied values of tensile stress, at the same time corrosion rate was determined potentiostaticaly. Potentiostatic investigation has been carried out in order to determine parameters describing corrosion rate of samples tested. Corrosion rate for the steel has decreased by orders of magnitude when covered with protective coating even though this latest became unseal at load exceeding. A small decrease of corrosion rate has been found for the steel that has not been covered with polymer coating when placed in model pore-liquid of concrete and exposed to tensile stress increasing. The aim of investigation that has been led was to evaluate tendencies of the corrosion process for St3S-b reinforcing steel when covered with polymer sulphuric coating and exposed to tensile stress. Steel samples were loaded in a way that their yield points were much exceeded; in the same time these samples were exposed to an action of the solution the composition of which is similar to that of pore-liquid of concrete is and additionally contaminated with chloride ions (pH = 9.14). The composition said was as follows: 0.015M NaHCO3 + 0.005M Na2CO3 + 0.001M NaCl. Corrosion rate for the steel has decreased by 2-3 orders of magnitude when covered with protective coating even though this latest became unseal at load exceeding 88.5 MPa.