The Temperature Field in Mass Concrete with Different Placing Temperatures

Hydration heat of concrete mix has an important role in the process of temperature increase in mass concrete at an early age. Thermal stress caused by the temperature difference between the core and the surface of mass concrete is the main reason in making thermal cracks if the stress is larger than the tensile strength of concrete. The aim of this study is to investigate the effect of placing temperature on temperature distribution and thermal stresses of mass concrete. A proportion of concrete mix of interest is used for the thermal analysis of a mass concrete sample sized 8×6×3 m. The finite element Midas Civil program is used to conduct the three-dimensional thermal simulation. Four typical scenarios of placing temperature in the range of (15-30) ℃ of the concrete mix, which is commonly used in actual construction condition, are presented. The analysis results of temperature distribution and thermal stress indicate that the value of 30 ℃ of placing temperature according to the selected proportion of concrete mix may cause thermal crack in the mass concrete. The study gives a useful way for practical construction application to avoid the risk of thermal crack in mass concrete at an early age.