American Society for Testing and Materials (ASTM). Current edition approved May 15, 2005. Published June 2005. Originally approved in 1966. Last previous edition approved in 1999 as C 586 – 99. 5 p. This test method covers the determination of the expansion of a specimen of carbonate rock while immersed in a solution of sodium hydroxide (NaOH) at room temperature. The length changes occurring during such immersion indicate the general level of reactivity of the rock and whether tests should be made to determine the effect of aggregate prepared from the rock upon the volume change in concrete.