Study on the Evaluation of Thermal Cracking Performance Using Urea Mixed Mass Concrete Based on FEM Analysis

Abstract

As domestic construction structures are becoming larger and larger, the hydration heat control of mass concrete is indispensable. In mass concrete, thermal stress is generated by hydration heat generation, and this thermal stress causes damage to the structure due to cracking. Various methods have been proposed to reduce temperature cracking, but recently, a method of reducing the heat of hydration using urea has been attracting attention. It is expected that urea will endothermic reaction with water to lower the heat of hydration and reduce the temperature crack of mass concrete. In this study, numerical coefficients for the FEM – based thermal crack analysis of urea concrete were derived and the thermal crack index of urea concrete was evaluated by the adiabatic temperature rise test and the compressive strength test. The adiabatic temperature rise of urea mixed concrete decreased by a maximum of 16.9 degrees, but the final temperature was the same. Compressive strength was relatively lower in early age than ordinary concrete, but the strength was the same at 28 days. In the FEM temperature crack analysis, the temperature was reduced by 4.0 degrees and the temperature crack index was increased by 0.1 at the initial age.