Mesoscopic simulation of crack propagation and bond behavior in ASR damaged concrete with internal/external restraint by 3D RBSM

Abstract

One of the most serious serviceability concerns for reinforced concrete (RC) structures is expansion and cracking resulting from the alkali-silica reaction (ASR), which has a negative effect on material properties as well as the bond between reinforcement and surrounding concrete. In a typical RC member, ASR induced concrete expansion and cracking are restrained by internal reinforcement as well as the boundary conditions. The mechanism is complex and difficult to understand through experimental study, so predicting the residual capacity of a damaged RC structure is not easy. In this study, the authors use a 3D Rigid Body Spring Model (RBSM) comprising mortar, aggregate and steel elements and which is able to simulate ASR expansion in reinforced concrete. To study the complex interactions among multiple parameters and quantify the effect of ASR damage on structural behavior, previously reported experiments on ASR induced expansion under internal and external restraint are simulated, along with experiments on pullout behavior after ASR expansion. The effect of restraints on macroscopic ASR expansion is well modeled in each case, and how the development of internal stresses and concrete cracking influenced by the restraint can be explained from the simulations. The simulations enable discussion of the number of ASR-induced cracks and the internal stress condition in various cases. The peak bond strength of concrete with different ASR damage levels, as reported in pullout experiments, is predicted accurately and the load-displacement curves of ASR damaged concrete are discussed.