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Use of the accelerated mortar bar test to evaluate the effectiveness of LiNO3 against alkali-silica reaction? Part 2: comparison with results from the concrete prism test

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1520/JAI101352
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FormatText, Article
SubjectMasonry walls; accelerated mortar bar test; alkali-aggregate reaction; lithium nitrate; pore solution
Abstract
For the time being, the concrete prism test (CPT) CSA A23.2-14A or ASTM C1293 remains the most reliable test method to evaluate the effectiveness of lithium nitrate against alkali-silica reaction (ASR) in concrete; however, the extended testing period of two years has often limited its acceptance by practitioners. In its actual form, the popular accelerated mortar bar test (AMBT) CSA A23.2-25A or ASTM C1260 cannot be used to predict this effectiveness, thus it needs to be modified accordingly. Part I of this study looked at the influence of a number of parameters on the effectiveness of lithium to control expansion of mortar bars incorporating a variety of reactive aggregates from Canada and the United States. The second part of this study (Part II) compares the results obtained in modified versions of the AMBT with those from the CPT performed on the same aggregates, with the objective of proposing the best accelerated test procedure for determining the minimum amount of lithium nitrate necessary to counteract ASR expansion in concrete. The results obtained in this study have shown that the effectiveness of lithium nitrate greatly varies from one reactive aggregate to another while not being correlated with the degree of reactivity or the petrographic nature of the reactive aggregates to counteract. A safe method of predicting the effective [Li]/[Na+K] to used in concrete is proposed which uses two AMBTs, one of which involves adding lithium to both the mortar bar and the soak solution. It allows the prediction of an effective [Li]/[Na+K] for aggregates that respond relatively well to lithium. The method allows the identification of aggregates that respond particularly badly to the lithium, for which the concrete prism test is recommended for evaluating the minimum lithium dosage to use for ASR control.
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  • Journal of ASTM International 5, no. 8 (1 September 2008).
LanguageEnglish
NRC numberNRCC 52704
NRC-IRC-20738
NPARC number15750137
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Record identifier1a555592-dc7b-4df1-b90e-cf648d172cb6
Record created2010-06-25
Record modified2022-07-22
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