The Influence Of Calcium Nitrate On The Compressive Strength Of Concrete Exposed To Freezing Weather

Abstract

Based on ACI 306R-88, the minimum temperature necessary for maintaining concretehydration and strength gaining is 50C. If the atmosphere weather becomes lower than 50Csome preserve measurements should be taken in order to prevent decrease in the rate ofhydration and to prevent fresh concrete from freezing. Most of the cold weather livingcountries spend annually plenty of money in order to facilitate concrete placing in the coldweather and to extend the construction season. It has been tried to carry out the behavior of fresh and hardened concrete contained calcium nitrate at different curing temperatures below freezing temperature of water and compare the results with the both control samples and real Erzurum winter conditions. For this reason, calcium nitrate is used at level of 6% by weightof cement dosage in the mixes. After casting, one group of concrete samples were cured in the different deepfreezes at -5,-10,-15,-200C for 7, and then that same samples were cured inwater for 28 days. With usage of calcium nitrate in the mixes, compressive strength of concrete increased between 96-297% at -50C, -100C, -150C and -200C, when compared tomixes without antifreeze admixtures that 7 days only freezer cured and 28 days water curedafter 7 days freezer cured, respectively. The results showed that it is possible to use calciumnitrate as an antifreeze admixture in concrete placing process in cold weather concreting.