Effectiveness of Lithium Nitrate in Mitigating Alkali-Silica Reaction in the Presence of Fly Ashes of Varying Chemical Compositions

Abstract

In this study, quantitative analysis of the combined effects of fly ash and lithium admixture in mitigating alkali-silica reaction (ASR) in portland cement mortars prepared with Spratt limestone was investigated. The results from this investigation suggested that mortar bar expansions could be correlated with specific oxide(s) content in the fly ash through exponential relationships. The dosage of lithium nitrate required for ASR mitigation in mortars containing fly ashes having CaO content less than 23.50% was found to be less than that in the control mortars. Since lithium nitrate was found to be effective in reducing the expansions of control (no fly ash) mortars and mortars containing fly ashes, economic solutions can be obtained in both. However, the use of lithium nitrate was not needed for mortars containing fly ashes having CaO content less than 14.40%. A linear relationship between the oxide content of fly ash and the lithium dosage was found to exist, that can be used to optimize the lithium dosage as a function of fly ash composition to provide an economic solution for ASR mitigation.