Evaluation of the Properties and Field Applicability of Non-shrink Mortar Containing Lithium Nitrite under Freezing Conditions

This study aims to develop a non-shrink mortar that cures properly under freezing conditions around −10°C without requiring heating or insulation. Mortars containing lithium nitrite (LN) were evaluated for strength development and expansion-shrinkage behavior when cured at −10°C immediately after mixing. Aluminum powder was also added to enhance non-shrink performance. To assess field applicability, outdoor exposure tests using specimens simulating bridge bearing mortar under freezing conditions were conducted. The results showed that adding LN at 4% or more prevented initial frost damage and allowed adequate strength development despite temperature fluctuations. Aluminum powder effectively induced slight expansion, compensating for shrinkage and ensuring dimensional stability. Even when temporarily exposed to temperatures below −10°C shortly after placement, the mortar exceeded the required compressive strength after 28 days and maintained dimensional stability. These findings suggest that the developed non-shrink mortar can be applied in cold environments without costly heating or insulation, offering a practical solution for cold weather construction.