Title: Creep Mechanism in Cement Mortar
Author(s): Joseph Glucklich and Ori Ishai
Publication: Journal Proceedings
Appears on pages(s): 923-948
A series of tests with a view to determining the true causes of concrete creep was carried out on cement mortar specimens. After drying and insulation from the atmosphere, specimens with’ varying water content were loaded in torsion and the instantaneous and time-dependent deformations measured. Results have shown a close connection between the evaoorable water content of the specimen on the one hand and the shrinkage, instantaneous deformation, and creep on the other. The most outstanding phenomena observed were the mutual dependence of the evaporable water and creep, the linear relation between gel water and the rate of creep and the almost complete disappearance of creep in specimens from which most of the evaporable water has been removed. As a main conclusion of the tests, the mechanism of creep is interpreted in terms of water migration within the voids of the specimen due to the action of the external load. This is followed by a theory providing a qualitative and quantitative explanation of the relation between the evaporable water content and the creep and instantaneous deformation, on the basis of the rheological behavior of a porous elastic body containing liquid in its voids.