Impact of atmospheric corrosion on the mechanical properties of B235 steel rods

Abstract

It is well known that atmospheric corrosion greatly affects the stress-strain properties of reinforcing steel. To be able to assess and forecast the remaining service life of constructions which have been subjected to atmospheric corrosion, it is necessary to have good knowledge of this effect. Research is often complicated to do due to the lack of accurate information on the initial dimensions of the steel parts and the properties of the material of which those parts are made. In this paper an attempt is made to overcome this obstacle. Reinforcing steel rods are tested. Those rods have been subjected to natural atmospheric conditions in a temperate climate zone for 25 years, in vertical orientation. To determine the initial stress-percentage extension curve of those rods test pieces have been made by machining on a lathe – to remove the corrosion layer and to set a standard diameter. The chemical composition and the density of the material are determined by appropriate experiments. The yield strength, the ultimate strength, the percentage elongation after fracture are determined by standard tensile testing. To determine the final stress-percentage extension curve, tensile tests are carried out with the corroded rods without any treatment. A comparison of both curves and analysis of the atmospheric corrosion effect on the stress-strain behavior is made.