Susceptibility to stress corrosion cracking of prestressing steel in NaHCO3

Abstract

The most important failure able to occur in a prestressing concrete structure are those due to steel corrosion cracking (SCC). The phenomenon, although it is not a very common one, is charactericed by its sudden and fast appeareance but the basic mechanism is still unknown. At the present, the effect when the steel is surrounded by a carbonated concrete has not been considered in SCC studies in prestressing steel. In this work the problem has been studied stressing in carbonated solutions which simulate the carbonate pore solution. It has been used electrochemical and slow strain rate techniques. The results show that prestressing steel is susceptible to suffer SCC failures in bicarbonated media. The failure depends on the NaHCO3 dependent. The appeareance of the fracture indicates that the growth of the crack is due to Hydrogen embrittlement but the mechanism of crack iniciation aremains unknown.