Investigating equivalency of different element models in discrete mesoscale analysis of ASR-damaged concrete

Abstract

The alkali-silica reaction (ASR) is one of the most serious durability issues affecting the safety of concrete structures. Numerical simulation is useful for monitoring the internal condition of an RC structure with ASR damage and predicting its long-term behavior. A mesoscale three-dimensional rigid body spring model (3D RBSM), a type of discrete analysis model, has previously been developed to simulate ASR expansion by modeling aggregate and mortar separately. The element size in simulations using this model (known as the aggregate model) is 2–3 mm, so the number of elements is huge and computation time correspondingly long. An equivalent model with lower number of elements is required, so in this study a concrete model based on RBSM is proposed. The aggregate is not separately modeled and expansive elements are included to simulate ASR expansion, allowing a larger element size (1–2 cm). The number of elements and computation time are less than 1 % compared with the aggregate model. This proposed model is used to simulate free ASR expansion, ASR expansion under confinement, and the mechanical properties of ASR-damaged concrete, as well as pullout behavior after ASR expansion. The simulation results are compared against previously reported results obtained using the aggregate model, as well as against experimental results. This comparison confirms equivalency between the concrete model and the aggregate model, opening the possibility of simulating ASR damage in RC structures in the future.