Advances in Test Methods to Evaluate Alkali-Aggregate Reactivity in Job Concrete Mixtures-Limitations to Current AAR Testing Methods and Proposed Solutions (Recorded presentation)

Limitations to Current AAR Testing Methods and Proposed Solutions (Recorded presentation)

Video Transcription

Video Summary

The presentation discusses the challenges associated with testing methods for Alkali Aggregate Reaction (AAR), specifically Alkali Silica Reaction (ASR) in concrete. Current standardized methods, such as those established by ASTM, are criticized for their unreliability and issues with alkali leaching, which can compromise test accuracy for certain aggregates. Examples are given from the Mactaquac Generating Station, where ASR has caused significant structural issues and led to costly maintenance. The speaker highlights the need for reliable tests that accurately evaluate reactive aggregates and the effectiveness of mitigation measures like fly ash. Alternative test methods, including field exposure blocks and new proposals like the concrete prism test with adjusted conditions, are explored. The presentation stresses the importance of developing more effective, reliable testing methods to determine optimal aggregate and mix combinations, ideally capable of rapid and comprehensive performance assessments.

Keywords

Alkali Aggregate Reaction

Alkali Silica Reaction

concrete testing

ASTM standards

Mactaquac Generating Station

mitigation measures