Corrosion Cracking Performance of Corrosion Resistant Steel Bars and Carbon Reinforced Concrete Columns under Axial Compression

Abstract

In order to study the difference in the development of corrosion expansion cracks between corrosion-resistant steel bars and carbon reinforced concrete columns, the accelerated corrosion method of dry-wet cycle and constant current energization was used to study the distribution, shape and crack width of corrosion expansion cracks over time. The research results show that: under the coupling action of axial compression load and chloride salt, the initial corrosion cracks of 5Cr corrosion-resistant reinforced concrete columns appear later than carbon reinforced concrete columns, and the direction of corrosion cracks is along the direction of the main reinforcement. There is nearly no rust expansion crack of stirrup. In the early stage of corrosion (theoretical corrosion rate less than 5%), 5Cr corrosion-resistant reinforced concrete columns are dominated by single-sided cracking, and the total length and expansion width of cracks are less than that of carbon reinforced concrete columns; the later period of corrosion (theoretical corrosion rate between 5% and 15%) Two types of reinforced concrete columns have obvious double-sided cracking. After a long period of corrosion by chloride salt, the total length and corrosion expansion width of cracks of 5Cr corrosion-resistant reinforced concrete columns increase faster than that of carbon reinforced concrete columns. The corrosion resistance “reversed” in the later stage of corrosion.