The three dimensional modelling of thermal cracks in concrete structure

The occurence of thermal cracks in massive concrete structures is a common phenomenon. In order to modell this kind of cracks the material properties of hardening concrete, temperature and stress developments must be dealt wi th. According to Laube [1] the thermal and mechanical properties of concret e may be expressed as functions of the reference parameter - the degree of hydration which depends on the hardening time and on the temperature proces s, therefore, a non-linear coupled calculation of temperatures and stresses should be carried out. On the basis of these material laws a numerical modell is set up for the pr ocess simulations of the material properties, the temperature and the stres s fields as well as the development of cracks. Then the modell is implement ed into a three dimensional finite element programme. As an example a fresh ly concreted wall on top of an old foundation is investigated. Finally atte ntion is paid to the numerical process modelling two typical thermal cracks , i.e, the surface cracks and the inner cracks, by employing the smeared ap proach of crack: distributions in three dimensional hardening concrete.