Grizzly Model of Fully Coupled Heat Transfer, Moisture Diffusion, Alkali-Silica Reaction and Fracturing Processes in Concrete

Abstract

Idaho National Laboratory (INL) has been developing a fully coupled thermo-hydromechanical-chemical (THMC) concrete model, referred as Grizzly, with the ultimate goal of reliably simulating and predicting the long-term performance of concrete structures subjected to various aging and degradation mechanisms. In this paper, we present a fully coupled concrete model implemented in our Grizzly code for simulating coupled moisture/heat transfer, stressdependent ASR swelling and elastic/inelastic mechanics. Example simulation results and preliminary model validation results against experimental data reported in the literature will be provided also in this paper. The close matches between the simulation results and experiments clearly reveal the potential of the fully coupled solution strategy for solving tightly coupled THMC concrete models. We also present simulation results of using a rate-dependent damaging mechanics model for simulating the ASR swelling induced degradation of concrete structures and its feedback to moisture and heat transport processes.

Modular system for probabilistic fracture mechanics analysis of embrittled reactor pressure vessels in the Grizzly code

“…In prioritizing research needs for Grizzly development, initial emphasis has been placed on RPV and concrete structure degradation [2] because issues with either could potentially limit the life of a nuclear power plant due to the extreme difficulty of their replacement.…”

Enhancements to Concrete Modeling Capabilities in Grizzly 2.0

“…Subsequent refinements and applications of this capability are presented in [4,5,6]. The initial implementation of a concrete capability in Grizzly was quite limited, and [6] identified several key missing features needed for realistic modeling of reinforced concrete structures: creep and damage models for concrete, a unified approach for modeling volumetric expansion due to ASR and radiation-induced volumetric expansion (RIVE), and a capability for modeling reinforcing bars.…”