Expansion behavior of two kinds of typical alkali reactive rocks specimen in alkaline solutions

Expansion behaviors of Spratt siliceous(SL)limestone and Pittsburg argillaceous dolomite-bearing(PL) limestone from Canada in Accelerated Mortar Bar Test(AMBT), Concrete Prism Test(CPT) and Concrete Microbar Test were studied. There are significant differences between the two rocks in the expansion behavior in different tests and in responses to the addition of sufficient amount of fly ash and LiOH, which are effective measures in controlling ASR expansion. SL limestone shows high expansion in both the AMBT and the CPT. By 30% replacement of cement with fly ash and LiOH the expansion of concrete microbar with SL limestone is reduced significantly. SL limestone is a high alkali-silica reactive limestone although the small amount of dolomite it contains might involve in reaction with alkali. PL limestone shows high and rapid expansion in the CPT, but little expansion in the AMBT. Fly ash and LiOH have no significant effect on controlling expansion of concrete microbar with PL limestone. ACR (alkali-carbonate reaction), which is very different from ASR(alkali-silica reaction), is the determining factor leading to the high expansion of PL limestone although the small amount of quartz it contains might involve in reaction with alkali and possibly contributes to the final expansion. It is critically important to use coarse particles that can maintain its original texture characteristics for proper evaluation of the alkali reactivity of PL limestone. The ASR and ACR in dolomite-bearing limestones could be classified in laboratory by using the different responses of ASR and ACR to fly ash and lithium chemicals, especially the duplex effect of LiOH on ASR and ACR.