Study on Physical Properties of Mortar for Section Restoration Using Calcium Nitrite and CO(2) Nano-Bubble Water

This study investigated the physical properties of section-restoration mortar with calcium nitrite (Ca(NO(2))(2)) and carbon dioxide (CO(2)) nanobubble mixing water to develop materials and methods for the repair and reinforcement of cracks in reinforced concrete (RC) structures. As the calcium nitrite content increased, the generation rate and generated amount of nitrite-based hydration products also increased, owing to the rapid reaction between NO(2)(−) ions in calcium nitrite and C(3)A(Al(2)O(3)). Further, the reaction with C(3)S and C(2)S was accelerated, thereby increasing the generation rates of Ca(OH)(2) and C-S-H. The large amount of Ca(2+) ions in these hydration products reacted with CO(3)(2−) ions in CO(2) nanobubble water, thereby increasing the generation of calcite-based CaCO(3) in the cement matrix. This appears to have affected strength development and durability improvement via the densification of the structure. These results suggest that the performance of polymer cement mortar for repairing concrete structures can be improved if calcium nitrite and CO(2) nanobubble water are properly combined and applied.