Experimental study and empirical modeling of lithium nitrate for alkali-silica reactivity

The influence of various dosages of lithium nitrate salt to inhibit the ASR-induced expansions of six reactive aggregates was studied. ASTM C 1260 (commonly known as Accelerated Mortar Bar Test (AMBT)), and modified AMBT were used to measure linear expansions of control mortar bars containing no lithium content and those of the mortar bars treated with up to six dosages of lithium-to-alkali molar ratios of 0.59, 0.74, 0.89, 1.04, 1.19 and 1.33, respectively. An empirical model to predict the minimums dosages of lithium salt required to suppress the excess mortar expansion below the prescribed failure limits at 14, 28 and 56 days was developed. The study revealed that a good correlation existed between the optimum lithium content obtained by the experimental procedures and that evaluated by the proposed model. It was also found that the amount of lithium nitrate salt needed to suppress ASR-induced mortar expansion varied depending upon the extent of aggregate reactivity, the mineralogy of the aggregates, and the test duration.