Abstract




 
   

IJE TRANSACTIONS C: Aspects Vol. 32, No. 3 (March 2019) 366-372   

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  EFFECT OF ANTIFREEZE ADMIXTURES ON COLD WEATHER CONCRETE
 
P. Narasimha Reddya and J. Ahmed Naqash
 
( Received: February 05, 2019 – Accepted in Revised Form: March 07, 2019 )
 
 

Abstract    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.

 

Keywords    Cold Weather Concrete; Elastic Properties; Mechanical Properties; Antifreeze Admixtures

 

چکیده   

کشمیر در منطقه‌ای است که دمای زمستان بسیار کم است. در طول ماه‌های زمستان، دما در کشمیر اغلب کمتر از 0 درجه سانتی‌گراد است. بتن عموماً در مناطق سرد با اشکال‌های عایق و همچنین بخاری‌ها برای محافظت از بتن تازه مخلوط در برابر انجماد قرار می‌گیرد. این شیوه‌ها کربن غیر ضروری را به کار می‌اندازند و منجر به پدیده کربن ناخوشایند می‌شود. هدف از این مطالعه ارزیابی قرار دادن بتن در دماهای سرد با استفاده از افزودنی‌های ضد یخ به جای اشکال یا بخاری‌های عایق است. هدف از این مطالعه، به منظور بهینه‌سازی نسبت دو افزودنی (نیتریت سدیم، کربنات پتاسیم) برای استفاده در بتن‌سازی آب و هوای سرد است. نمونه‌های بتنی برای ارزیابی خواص مانند مقاومت و خواص کششی مورد آزمایش قرار گرفتند. نمونه‌ها در دو مرحله به عنوان مثال در شرایط زمستانی بیرونی و تحت شرایط کنترل -5 درجه سانتی‌گراد با درصد متنوعی از افزودنی‌ها مورد بررسی قرار گرفتند. در مقایسه با مخلوط بدون افزودنی ضد یخ، نتایج افزایش مقاومت مصالح بتن با افزودن 3٪ کربنات پتاسیم و همچنین 5/3٪ نیتریت سدیم به ازای وزن سیمان به دست می‌آید که برای محدوده دما مطلوب است.

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