Work Item
ASTM WK88179
New Test Method for Determination of Alkali Sensitivity of Aggregate using Concrete Prisms
1. Scope
This test method covers the determination of the sensitivity of an aggregate to a range of alkali loadings. It can also be used to determine the combination of an aggregate with supplementary cementitious materials for potentially deleterious alkali-silica reaction by measurement of length change of concrete prisms.
Keywords
alkali-silica reaction; alkali sensitivity; supplementary cementitious materials
Rationale
Recent research has developed a powerful new way to evaluate the potential alkali-silica reactivity of aggregates. Alkali sensitivity of aggregates has been documented in the literature but was never fully explored, perhaps due to the complexity of evaluating individual aggregate sources. This approach relies on determining the alkali sensitivity of aggregates. The aggregate is cast in concrete prisms and exposed to a variety of alkali loadings in an immersion test run at 60 C. This approach has been shown to better predict the potential for alkali-silica reactivity than current methods that suffer from a number of drawbacks including alkali leaching (ASTM C1293), high temperature (ASTM C1260/1567) and crushing of coarse aggregates which leads to false positives (ASTM C1293). The results of this method can be combined with the available alkali from the cementitious blend (e.g. portland limestone cement + candidate supplementary cementitious material) to determine the appropriate replacement level of SCM to prevent deleterious alkali-silica reaction. This represents a paradigm shift in the way we will evaluate the potential for ASR and the prevention of it. Current research efforts show this is a scientifically supported approach that better captures the key factors in alkali-silica reaction compared to our current methods (e.g. C1260/1567/1293).
The title and scope are in draft form and are under development within this ASTM Committee.
Work Item Status
Date Initiated: 10-18-2023
Technical Contact: Jason Ideker
Item: 000
Ballot:
Status: