Common thermal and shrinkage cracking of ceiling slabs

Abstract

Early age cracks of concrete structures are usually associated with the phenomenon of shrinkage. Most often they appear after a few days of hardening of the concrete. The appearance of shrinkage cracks results from the constraint of the structure, including inhomogeneous volume changes of the concrete. Due to the variety of reasons that can cause early age cracks, it is often difficult to diagnose them properly, and especially to recognise them from the more serious damages caused by load capacity deficits. The paper presents a few cases of shrinkage cracks of ceilings, met by the authors in their professional work. The examples were selected to show different types of design and construction errors that contributed to the occurrence of excessive shrinkage cracking. These include maladjustment of concrete care for the weather conditions, local structural restraints that limit the freedom of deformation of the ceiling, the lack of expansion joints or too large breaks in concrete placing.