Title: Influence of Alkali-Silica Reaction Reactivity on Corrosion in Reinforced Concrete
Author(s): David Trejo, Vandad Mazarei, Jason H. Ideker, and O. Burkan Isgor
Publication: Materials Journal
Appears on pages(s): 723-731
Keywords: alkali-silica reaction (ASR); ASR gel; corrosion; critical chloride threshold; diffusivity; interfacial transition zone
Alkali-silica reaction (ASR) and reinforcement corrosion are wellknown deterioration mechanisms in concrete structures. This research investigates how ASR affects corrosion in reinforced concrete specimens. Concrete specimens containing aggregate susceptible to ASR (reactive) and aggregate not susceptible to ASR (nonreactive) were cast. Expansion of the specimens, corrosion potential, macrocell current, and chloride diffusivity were measured for each specimen until the embedded reinforcement began to actively corrode. Scanning electron microscopy (SEM) results indicate that ASR gel can fill the interfacial transition zone (ITZ) and cracks, which can reduce the transport of the chlorides in concrete. The presence of ASR gel at the HCP-steel interface likely reduces the pH at the interface, which can reduce the critical chloride threshold level (CT). The results indicate that ASR expansion does not significantly influence the time to corrosion initiation of reinforced concrete systems for laboratory specimens exposed to wetting/drying cycles at 100°F (38°C).