Work Item
ASTM WK88785
Revision of C1778-22 Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete
Rationale
Work Item: Remove Fig 1 (Flow Chart) and revise Section 6 Procedure and Section 7 Determining Aggregate Reactivity
Rationale:
The inclusion of the flow chart helps to preclude and excuse users from reading the document. Without reviewing the text of the document, the user can leave without an understanding of the context within, that has been carefully developed through a discussion of the methods for assessment of the ASR potential of an aggregate, levels of risk assessment, and mitigation approaches. When this occurs the role of this document as a guidance document fails. In reviewing current ASR specifications in practice, and working to meet these, it is apparent that this happens all too frequently. The document while meant as a guide is being inserted as a must follow specification into project contract documents without proper understanding of the text within.
The practice of using this guide without understanding the context and details within, has produced published project specifications that have resulted in serious issues including:
• Sole reliance on ASTM C1260 test results. This has allowed aggregates with false negatives to be put in service, resulting in significant expense to replace pavements and structures within a few years following their construction.
• Specifications that preclude the use of aggregates classified as moderately reactive from being used into non-exposed or non-critical applications where the mitigation measures noted would be effective.
• Mitigation requirements over and above what is recommended in this guide for the appropriate level of risk or exposure of the concrete construction element. This has resulted in scaling and other durability issues.
There is a habit within our industry to rely on a single recent laboratory test to provide a quick yes or no, good or bad, pass or fail result to qualify our construction materials. The complex nature of determining the potential for deleterious ASR and if required, proper mitigation is challenging enough utilizing the currently approved laboratory tests. The flow chart further encourages this short-sighted practice.
ASTM C1778 is recognized as the source for the most current state of knowledge on ASR, and to be used as a reference for preparation of construction specifications. The removal of the flow chart will benefit users and industry at large by helping to promote a wider understanding of the complex issue of assessing the potential for deleterious ASR by requiring users to read the guide, and therefore specify appropriate mitigation measures with respect to risk and constructability concerns.
Work Item Status
Date Initiated: 12-01-2023
Technical Contact: JAMES CASILIO
Item: 000
Ballot:
Status: