Interaction between thermal dilation and autogenous deformation in high performance concrete

Abstract

The paper concerns the driving forces to stress generation and cracking in high performance concrete,i.e. thermal dilation and autogenous deformation and presents experimental results from a recently finalized Dr. program. The paper focuses on the effect of temperature, and discusses how to separate thermal dilation and autogenous deformation with the view to describe each with a model for use in stress calculations. The results show clearly that especially autogenous deformation is very complicated since autogenous deformation from isothermal tests appears to be fundamentally different from autogenous deformation in tests using realistic temperature development. The implication is that autogenous deformation under realistic temperature development cannot be predicted from isothermal test results and that the simple maturity concept cannot be used. The paper gives a new experimental approach to separate thermal dilation and autogenous deformation. The results from such tests show, that the thermal dilation coefficient varies more systematically with temperature. Consequently, the maturity concept appears to be more usable for the thermal dilation coefficient.