Stress corrosion of prestressed steel in alkaline media with sulphates

Abstract

In this paper, the influence of the presence of sulphates in alkaline media simulating the pore concrete solution has been considered. The tests were carried out on cylindric speciments submitted to axial stress at a constant strain rate. The aggressive condition employed were saturated Ca(OH)2 solutions with 0.2 M K2SO4 (pH = 12.8) and aerated. The vairables studied were the strain rate and the electrochemical potential. The results indicate that tehre are two potential regions susceptible to brittle fracture due to a stress corrosion phenomenom. One at potentials more negative than -900 mV and other between -200 to +200 mV, this last having also a heavy local attack.