Title:
Early Detection of Alkali-silica Reactivity in Laboratory Concrete Prisms Using Ultrasonic Coda Wave Monitoring
Author(s):
Sina Mehdinia
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
Current standardized monitoring methods for detecting alkali-silica reaction (ASR) in laboratory concrete prisms rely on manual measurements and are time consuming. Active and passive stress wave-based methods such as ultrasonic and acoustic emission monitoring, respectively, represent promising tools to not only automate the process but also detect the onset of ASR much earlier. In this research, a simple but reliable monitoring method for early detection of ASR in laboratory concrete prisms was developed and evaluated. The approach takes advantage of the highly sensitive coda wave eld of recorded ultrasonic signals. A robust laboratory setup was developed following a year of experimentation. Three concrete mixtures with different target reactivity levels containing various dosages of lithium nitrate were monitored over 84 days. The results were compared to expansion measurements based on ASTM C1293. The proposed approach, based on ultrasonic coda wave elds, correlates well with expansion data, shows to be highly sensitive, and can detect the onset of ASR much earlier than the 1-to-2-year ASTM C1293. A further bene t of this approach is that the measurements are directly relatable to the physical process occurring in the material and can be captured with mathematical prediction models.