Effect of Antifreeze Admixtures on Cold Weather Concrete

Kashmir is located in a region where winter temperatures are very low. During the winter months, the temperature in Kashmir is often below 0⁰ C. Generally concrete placed in colder regions with the help of insulated forms as well as heaters to protect freshly mixed concrete against freezing. These practices try to incorporate unnecessary carbon and leads to an disagreeable carbon footprint. The aim of this study was to evaluate the placing of concrete in colder temperatures with the help of antifreeze admixtures rather than insulated forms or heaters. The objective of this study was to optimize the proportions of two admixtures (Sodium nitrite, Potassium carbonate) to be used in cold weather concreting. Concrete specimens were tested to evaluate the properties such as Strength and elastic properties. The samples were cast in two phases i.e. in exterior winter conditions and under controlled conditions of -5°C with varying proportions of the admixtures. When compared to mixes without antifreeze admixtures the results showed increase in the strength of the concrete samples with addition of 3% Potassium carbonate as well as 3.5% Sodium nitrite by weight of cement was found to be optimum for the temperature range in consideration.