Long-term mitigating effect of lithium nitrate on delayed ettringite formation and ASR in concrete - Microscopic analysis

In the present study, microstructural features associated with microcracking and ettringite infilling showed relatively reduced intensity of internal distress and damage when lithium nitrate was admixed in DEF expansive concrete. Microanalyses plotted as Al/Ca versus S/Ca shows that, the use of lithium nitrate leads to formation of non-expansive delayed ettringite similar to normal early-age ettringite formed in moist-cured concretes. These observations give some insights into the mechanism responsible for mitigation of DEF by lithium nitrate.