Dr. Michael Berry, Associate Professor-Civil Engineering Department-Montana State University–Bozeman
The Montana Department of Transportation (MDT) has released a report that identifies existing Alkali-Silica Reactivity (ASR) damage in Montana. It also investigates the potential underlying geological features that may contribute to the presence of reactive aggregates. ASR is a harmful reaction that takes place in concrete between alkalis and reactive forms of silica in aggregates, which leads to reduced life span, costly repairs, and/or the replacement of the concrete.
Alkali-Silica Reactivity (ASR) is a deleterious reaction that takes place in concrete between alkalis present in the portland cement and reactive forms of silica in the aggregates. ASR can cause significant damage leading to reduced life span, costly repairs, and/or the replacement of the concrete. This damage is caused by the swelling (in the presence of water) of a gel that forms on the surface of the reactive aggregates, and typically results in map cracking. While ASR has been documented as an issue in many states, little work has been conducted to determine the presence/potential of ASR in 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.
The specific tasks associated with this research are as follows:
Task 1 – Literature Review
Task 2 – Determination of ASR Testing Protocol
Task 3 – Identify and Document Cases of ASR Damage in the State
Task 4 – Analysis of Results and Reporting
This report documents the work completed as part of Task 1 – Literature Review. It should be noted, that this literature review will continue to be updated as new research on this subject becomes available. This report first provides some background on ASR, and then discusses the ASR practices in surrounding states and within several federal agencies. It concludes with a brief summary of existing and newly developed ASR testing methods.
Reactive aggregates and the associated damage resulting from their use are known to be an issue in the region. Specifically, damage to hardened concrete due to ASR has been observed in all states adjacent to Montana [5], as can be seen in Figure 2.
For the full report PDF, please go to: https://www.mdt.mt.gov/Other/Webdata/External/Research/Docs/Research_Proj/Alkali/Task_1_Report.Pdf