关键词: 缓凝剂;膨胀剂;水化温峰;水化热

Abstract: The effects of retarder on the hydration heat process of cement paste mixed with expansive agent were studied using a differential calorimeter, two types of retarders were used as followings:tartaric acid and boric acid, two types of expansive agents were used as followings: calcium hydroxide expansive agent and calcium sulphoaluminate hydrate-calcium hydroxide expansive agent.The terminal time of induction period, the time of the appearance of the temperature peak and maximum rate of hydration heat evolution, the heat of hydration at different ages were investigated.The results show that the two retarders can postpone the terminal time of induction period and the time of the appearance of the temperature peak in cement paste mixed with expansive agent, reduce the maximum rate of hydration heat evolution and the total hydration heat of 24 h, the total hydration heat of 72 h is slightly low, compared with cement mortar mixed with expansive agent.The retarding effect of boric acid is better than tartaric acid in cement paste mixed with calcium hydroxide expansive agent.

Key words: retarder;expansive agent;temperature peak of hydration;hydration heat