Z7-06 Concrete Cracking and Crack Control

Cracks in most concrete structures are to be expected and to ensure that they do not impact adversely on the serviceability and durability of the structure can be a challenging task. Plastic cracks in the wet concrete during construction are sometimes inevitable despite all reasonable construction actions to minimise them. Cracks in the hardened concrete caused by a combination of thermal contraction, shrinkage and load are to be expected, and design is generally based on limiting their width rather than preventing them altogether. A key issue when a crack forms during construction is the consequence of the crack, in particular the effect of its width and depth on durability, structural and operational integrity and aesthetics throughout the design life of the structure.

This document Z7-06 provides up-to-date guidance on concrete cracking and the design for crack control for Australian structures, as well as the assessment, monitoring and repair of cracks. The causes and factors affecting cracking in concrete structures are discussed and procedures for minimising the adverse effects of cracking are presented. In addition to providing reliable design guidance on the control of cracking in new structures to ensure serviceability and durability, the advice provided will also assist designers to diagnose the cause of cracks in existing structures and, where appropriate, to specify effective remedial measures.

Z7-06 is intended to complement the relevant provisions of Australian Standards and gives relevant reference to international standards, codes and technical society publications. The document can be used in other countries with due consideration of local standards and codes. It is hoped that it will form the basis of improved design procedures for crack control, improved construction practices to minimise plastic cracking, and improved guidance for the assessment and repair of cracks in concrete structures both in Australia and elsewhere.