ABSTRACT
In freshly cast concrete structures the temperature rise caused by the hydration process is often considerable and may extend over a long period of time. If unrestrained, the concrete would expand and contract during the heating and the subsequent cooling process without stresses being induced. In practice, however, the concrete is nearly always restrained to some degree either by adjoining structures or by different parts within the concrete itself. Thus, due to these imposed restraint conditions, the temperature change will induce compressive and/or tensile stresses in the element. A question of primary interest is of course whether the induced tensile stresses will lead to thermal cracking or not, Emborg (1989). Cracks may be of two kinds:
(1) Surface cracks caused by the restrained volume changes within the element. (2) Through cracks over the entire cross section caused by volume changes restrained by external factors
such as adjoining structures of previous casts or by the foundation.
