The alkali-silica reaction (ASR) is an important mechanism for time-dependent degradation in a variety of reinforced concrete (RC) structures worldwide. Nuclear structures are also susceptible to ASR, as evidenced by a containment vessel at an operating commercial reactor in the United States being actively monitored for the progression of its identified ASR. The ability to simulate the progression and effects of
ASR is an important component of an ASR management program. Because ASR is affected by the local temperature, moisture, and stress conditions, this situation calls for coupled physics modeling. We applied a coupled thermo-hygro-mechanical model that uses existing models for ASR expansion, transport of humidity and temperature, and concrete creep to examine the progression and effects of ASR degradation in a 3D continuum model of a representative RC nuclear containment vessel structure.
This model accounts for the temporal and spatial variation of temperature and the effects of moisture in the soil and air on the boundaries of the model. This simulation methodology is validated using existing experimental studies on RC beams subjected to varying environmental conditions and rebar confinement. The results show how the model captures the significant effects of local temperature and moisture and
rebar confinement.