Prediction of Temperature in Ultra High-Strength Concrete Based on Temperature Dependent Hydration Model

摘要

High strength concrete, which is characterized by a low water to cement ratio, has a greater cement content than ordinary concrete. Even if the cross sectional area of reinforced concrete member is reduced on account of high strength, significant temperature rise at an early age can be observed because of the higher cement content per unit mass of concrete. This can jeopardize durability and the appearance of concrete members due to early age cracking. Regarding this problem, it is of vital importance to be able to predict the temperature history in concrete members. This is especially true in the case of small section members where the temperature dependency of cement hydration is difficult to predict. In this study, temperature distribution in concrete members made of ultra high-strength concrete with water to cement ratio of 0.15 is investigated. In order to predict the temperature distribution, a cement hydration model which takes into account temperature effect on the rate of cement hydration is proposed. Also, a finite element analysis considering temperature dependent heat production is conducted for evaluating temperature history and distribution in concrete. The proposed hydration model and analysis method are discussed along with experimental results.