Recommendation of RILEM TC 258-AAA: RILEM AAR-8: determination of potential releasable alkalis by aggregates in concrete

The test method AAR-8 is intended to be used for assessing the potential amount of alkalis released by aggregates in field concrete in the long-term. This is done by measuring the amounts of sodium and potassium ions released from the fine graded (< 4 mm) aggregate immersed in (0.7 M) KOH and NaOH solutions, respectively, at elevated temperature when in contact with excess calcium hydroxide. It is of great importance to realise that this accelerated test method must be considered as a mere indication of potential (maximum) alkali release by the aggregates, rather than a quantification used for the alkali inventory calculations.

Automated summary

The AAR-8 test method is used to assess the potential amount of alkalis released by aggregates in concrete by measuring the sodium and potassium ions released from fine graded aggregate immersed in KOH and NaOH solutions. It is important to note that this accelerated test method is only an indication of potential alkali release by the aggregates, rather than a quantification for alkali inventory calculations.