Subcritical Crack Growth Induced by Stress Corrosion in Hardened Cement Paste

Abstract

For concrete structures a primary driver of deterioration shortening their lifespans is the damage growth resulting from coupled chemo-mechanical attack. Under sustained service load coupled with corrosion, stress corrosion cracking will happen and lead to subcritical crack growth (SCG) in concrete members. In this study, the kinetics of crack growth in cement paste under concurrent mechanical and chemical attacks will be investigated experimentally. To obtain the complete crack velocity versus stress intensity factor (K-v) curve, tests will be designed for experimental characterization to track the subcritical crack growth. In the test the specimens, which are immersed in a corrosive solution of high concentration, will be subject to sustained loading. To record the crack propagation as well as strain/stress distribution around crack tip, a high-resolution microscopic system and a non-contact digital image correlation (DIC) system will be used to scan the specimen surface. The recorded (K-v) curves show that the proposed specimens, which are of a negative geometry, are capable of capturing the subcritical crack growth by using load control, and thus provide a novel alternative for characterizing the stress corrosion cracking in cementitious materials.