Unique response of LiNO3 as an alkali silica reaction-preventive admixture

Abstract Lithium hydroxide and various lithium salts have been known to ameliorate the effects of alkali silica reaction for many years. The use of lithium hydroxide is not without risk. A significant increase in the pore solution OH− ion concentration (and pH) by lithium hydroxide and inadequate dosages are known to result in increased, rather than decreased expansion. Almost insoluble lithium salts (such as lithium fluoride and lithium carbonate) are effective at large dose levels, but generate lithium hydroxide in solution, and are thus subject to the same difficulty as LiOH. It is shown that lithium nitrate, a fully soluble neutral salt, does not generate significant increases in hydroxide ion concentration, and thus does not undergo the risk of accelerating the alkali silica reaction at the same time that it is attempting to ameliorate its effects. Lithium nitrate is, however, subject to the same extensive sorption by newly forming cement hydration products as other forms of lithium treatment, and a high dosage level is needed to indefinitely maintain the requisite concentration in solution.