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.