ASTM C289

Potential Alkali-Silica Reactivity of Aggregates (Chemical Method)

Applicability: Historically applied to fine aggregates and crushed coarse aggregates (ground to fine size) used in portland cement concrete, covering natural and manufactured mineral aggregates from any geological source. This standard was formally withdrawn by ASTM in 2016 and is no longer maintained or sold as an active method; users are directed to ASTM C1260 (accelerated mortar bar) or ASTM C1293 (concrete prism) for current alkali-silica reactivity testing. The method was used as a rapid screening tool but had documented risks of both false positive and false negative results.

Purpose: Immersed a crushed aggregate sample in 1N NaOH solution at 80°C for 24 hours, then measured dissolved silica (Sc) and reduction in alkalinity (Rc) to classify aggregates as innocuous, potentially deleterious, or deleterious for use in concrete. The test was valued for its speed (24-hour turnaround compared to weeks or months for mortar bar or prism tests) but was withdrawn due to poor correlation with long-term field performance, particularly for slowly reactive aggregates such as certain granitic rocks and quartzites.