• TANVEER AHMAD
• Mohd Zeeshan Khan
• Er A.A. Masoodi

: Based on ACI 306R-10, the minimum temperature necessary for maintaining concrete hydration and strength gaining is 5 °C. If the temperature becomes lower than 5 °C, special measures should be taken in order to prevent decrease in the rate of hydration and to prevent fresh concrete from freezing. Concreting in winter conditions is very difficult. The reason is that concrete can harden and develop high strength in a relatively short time only within a certain range of above-zero temperatures. It is possible to create favorable conditions for concrete to harden when the ambient air temperature is below zero but that requires additional energy, materials and labour. During cold weather, preparations are made to protect the concrete; enclosures, windbreaks, portable heaters, insulated forms, and blankets are used to maintain the concrete temperature. As an alternative, antifreeze additives can be used in cold weather. These chemical additives suppress the freezing point of water under 0 °C degrees and accelerate the hydration of cement. However, the long term effects of these additives remain unknown. The selection of an antifreeze admixture will depend on the type of structure, the operating conditions and whether the admixture will be used with other protective methods of winter concreting. It is important therefore to determine through laboratory mix trials both the operating range and the particular dosage of the admixture required for the intended application. Cold-weather concreting with antifreeze admixtures does not exclude the use of other admixtures such as air-entraining agents, water reducers, retarders and super plasticizers. However, the dosage of the specific admixture to be used in combination with the antifreeze admixture should be established experimentally, because higher than normal amounts may be required. Concrete antifreeze additives are an indispensable component of concrete, particularly in winter and in areas with a cold climate. The overall effects of these additives, which are thought to have overall positive effects, should be determined and these effects should be taken into account in the design process. This study is conducted to study the effects of antifreeze (Sodium Nitrite plus Potassium Carbonate) on the strength properties of the concrete produced in cold weather. The concrete samples will be prepared with different percentages of admixtures (0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5% by weight of cement). Prepared concrete samples are to be placed in a formwork and exposed to the sub-zero temperatures (exterior winter conditions) and compressive strength & tensile strength of the concrete samples will be determined after the curing. In conclusion, the effect of antifreeze agents on the properties of concrete will be determined.

- Ant freezing Concrete, Sodium Nitrite, Potassium Carbonate

"OBTAINING THE OPTIMAL PERCENTAGE OF ANTIFREEZING ADMIXTURES (SODIUM NITRITE AND POTASSIUM CARBONATE) EFFECTING THE STRENGTH PROPERTIES OF CONCRETE ", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.5, Issue 7, page no.592-598, July-2018, Available :http://www.jetir.org/papers/JETIR1807093.pdf

"OBTAINING THE OPTIMAL PERCENTAGE OF ANTIFREEZING ADMIXTURES (SODIUM NITRITE AND POTASSIUM CARBONATE) EFFECTING THE STRENGTH PROPERTIES OF CONCRETE ", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.5, Issue 7, page no. pp592-598, July-2018, Available at : http://www.jetir.org/papers/JETIR1807093.pdf