Influence of sodium and potassium chlorides on the hydration kinetics and its impact on the strength

• 作 者: C.A.A.Rocha[1]G.C.Cordeiro[2]R.D.ToledoFilho[1]
• 机 构: Civil Engeenering Program-PEC, Universidade Federal do Rio de Janeiro-COPPE/UFRJ, Rio de Janeiro,RJ,
• 出 处: The 14th International Congress on the Chemistry of Cement (
• 发表日期: 2015年期

　　In this paper, the hydration process of Portland cement with NaCl and KCl addition was studied by isothermal calorimeter, ultrasonic method and compressive strength.Pastes were designed containing 5%, 10%, 15%, 20% and 36% NaCl by the weight of water (BWOW), and 5%, 10%, 15%, 20% and 34% KCl (BWOW) and water to cement ratio of 0.44.The results of these tests were correlated with the amount of the formed hydration products obtained by thermogravimetfic analysis and the compressive strength.The addition of NaCl up to 15% accelerated the hydration reactions at the first ages.On the other hand, 20 and 36% of NaCl addition delayed the hydration reactions.At older ages, all pastes with NaCl addition had their reactions delayed;it directly influenced the amount of formed products and the compressive strength.The KCl addition accelerated the hydration reactions at the first ages, with exception of paste containing 34% KCl.The addition of KCl have not significantly influenced the amount of the formed products and mechanical properties at long periods.