ASTM C1260-21 PDF Download

The ASTM C1260-21 standard provides a way to determine the potential of aggregates used in concrete to undergo alkali-silica reaction, which can lead to detrimental internal expansion. This test method is based on the NBRI Accelerated Test Method and is particularly applicable to aggregates that exhibit slow reactions or delayed expansion. However, it does not assess the combination of aggregates with cementitious materials, nor does it replicate the conditions experienced by concrete in actual service.

One important aspect of this test method is that the alkali content of the cement does not significantly affect the expansions of the specimens, as they are exposed to a NaOH solution. In cases where excessive expansions are observed, it is recommended to gather supplementary information to confirm that the expansion is indeed due to alkali-silica reaction. This can be achieved through petrographic examination of the aggregate, examination of the specimens after tests to identify alkali reaction products, and the use of field service records to assess performance, if available.

If it is determined, based on the results of tests performed using this method and supplementary information, that an aggregate is potentially deleteriously reactive, mitigative measures such as the use of low-alkali portland cement, mineral admixtures, or ground granulated blast-furnace slag should be evaluated for implementation.