STUDY ON MODULUS OF RUST APPLIED IN STEEL CORROSION INDUCED CONCRETE CRACKING MODEL

After steel corrosion initiates, the volume of rust is larger than the original steel, inducing an internal pressure on the surrounding confining concrete to crack the cover. Therefore, the rust is one of the most influential factors during the concrete cracking process due to corrosion. Five natural rust and one electrochemical steel corrosion were investigated in this study. The oedometer tests were used to analyze the mechanical behavior of the powder rust samples, the modulus of these six types of rusts were then deduced according to Hertz' contact theory. The experimental results show that the modulus of rust increased with the load increasing, the rust is not a linear elastic material behavior. The natural rust and the electrochemical steel corrosion have different mechanical properties; therefore, the investigation of natural rust can not be replaced by that of the electrochemical corrosion products. The rust samples with different sizes have different mechanical properties, the modulus of rust decreases with the increase of its volume and tends to be a constant, 10(2) MPa, which can be referred to when analyzing the concrete cover cracking due to reinforcement corrosion.