Deformation and stress in high-strength concrete due to autogenous shrinkage and thermal expansion

Autogenous shrinkage and thermal expansion/contraction due to hydration generate complex deformation and stress in high-strength concrete at early age, which may induce severe cracking. However, there are only few investigations on those phenomena in structures under realistic temperatures. This paper reports the observed deformation and stress of a concrete specimen cured under semi-adiabatic conditions and restrained by steel bars. Values between 0.2 and 0.4 were adopted for the water-cement ratio (w/c). The deformation was separated into the autogenous shrinkage and the thermal expansion, taking change of thermal expansion coefficient with age into account. In addition, the simulated stress in the structures was estimated based on the elastic modulus and the tensile creep coefficient of the concrete. The results show that the approach of separating the deformation and the method for estimating stress are useful for the analyses in high-strength concrete structures.