Montana Department of Transportation

Malcolm “Mack” Long, Director


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Alkali-Silica Reactivity in the State of Montana

ASR cracking observed on bridge over Belt Creek Montana

Concrete can be susceptible to expansive reactions between alkalis in the Portland cement and the silicas in the aggregates, which can ultimately reduce the lifespan of the concrete resulting in costly repairs or even replacement. The primary objective of this project is to evaluate the history of and potential for deleterious alkali-silica reactivity (ASR) in the state of Montana.

The primary objectives of the proposed research are to evaluate the potential for deleterious ASR in the state of Montana, and to develop a testing protocol for identifying potential reactive aggregates. This research will also identify/document existing ASR damage in the state, and investigate the potential underlying geological features that may contribute to the presence of reactive aggregates. Finally, this research will explore the efficacy of potential mitigation techniques employed to limit the effect of ASR.


  • Final Report
  • Final Presentation (pending)
  • Project Summary Report (pending)
  • Implementation Report (pending)
  • Performance Measures Report (pending)
  • Poster (pending)

Supplemental Material