Thermal analysis and adiabatic calorimetry for early-age concrete members

In this study, a finite element model was developed to perform the stress analysis on early-age concrete members to predict the thermally induced stresses and the associated cracking risk. FORTRAN subroutines were created for ABAQUS finite element program to enable solution-dependent material properties in the thermal stress calculation. Young’s modulus development, strength development, tensile creep, and compressive creep behaviors at early age were experimentally obtained, and these material properties were incorporated in the subroutines. Two 1.2-m concrete cubes were constructed with embedded temperature sensors and vibrating wire strain gages to verify the simulation results. Results showed that the calculated temperature and strain values correlated well with the measured field data. Additionally, visual cracks were confirmed at the predicted locations on the concrete cube. It is concluded that the method developed in this study is capable of determining the thermally induced stresses of early-age concrete members.