Title: Alkali-Silica Reaction for Concrete Confined with Carbon Fiber-Reinforced Polymer Sheet
Author(s): Yail J. Kim, Yongcheng Ji, and Wei Li
Publication: Structural Journal
Appears on pages(s): 15-27
Keywords: alkali-silica reaction (ASR); carbon fiber-reinforced polymer (CFRP); damage; rehabilitation; strengthening
This paper presents a comparative experimental study on the axial behavior of concrete subjected to alkali-silica reaction (ASR) with and without confinement by carbon fiber-reinforced polymer (CFRP) sheets. A total of 120 cylinders are cast using two types of coarse aggregates to represent variable levels of ASR: rhyolite (reactive) and substitutes granite (non-reactive) at a replacement ratio ranging from 0 to 100%. As per a test standard, the cylinders are conditioned in a sodium hydroxide (NaOH) solution. The physical properties of the concrete and the solution are measured over time to examine the reciprocal action between the NaOH and rhyolite, followed by microscopic observations on the progression of ASR through the concrete. Sixty cylinders are confined and all specimens are monotonically loaded to failure. The load-carrying capacity of the confined cylinders noticeably increases compared with that of the plain concrete, while the degree of improvement is controlled by the ASR-damaged concrete core. The average toughness of the cylinders decays with ASR, accompanied by irreversible energy dissipation and degraded CFRP-concrete interaction. The failure characteristics of both plain and confined cylinders are also influenced by ASR, dependent on the replacement ratio, particularly for the integrity of the core. An analytical model is
formulated to understand the implications of ASR, including an assessment of an existing design approach, and is further used for design recommendations.