Strength Development of Cement Paste Using Nitrite Below Freezing Point

Abstract

Anti-freezing agents are commonly used in cold-weather concreting, in which the ambient temperature is generally maintained at +5 °C or more for 24 h after casting in the mold. Consequently, the freezing inhibition effect and strength development of cementitious materials exposed to a low temperature (below the freezing point) immediately after mixing with an anti-freezing agent, remain unclear. In this study, several physicochemical reviews were performed to clarify this relationship between the strength development and hydrate formation behavior at the freezing point immediately after mixing, resulting from the addition of different amounts of anti-freezing agents to cement paste. Lithium nitrite and calcium nitrite were used as the anti-freezing agents. The freeze temperature of the cement paste with lithium nitrite was lower than that of the cement paste with calcium nitrite when cured at -10 °C immediately after mixing. An increase in the amount of lithium nitrite prevented the freezing of cement paste and promoted the hydration reaction even below the freezing point, thereby contributing to strength development.