Stress-based crack criterion as a basis for prevention of through-cracks in concrete structures at early ages

Title: Stress-based crack criterion as a basis for prevention of through-cracks in concrete structures at early ages
Author(s): K. van Breugel, S.J. Lokhorst
Paper category : conference
Book title: International RILEM Conference on Early Age Cracking in Cementitious Systems
Editor(s): K. Kovler and A. Bentur
Print-ISBN: 2-912143-29-2
e-ISBN: 2351580362
Publisher: RILEM Publications SARL
Publication year: 2003
Pages: 229 - 236
Total Pages: 8
Nb references: 10
Language: English

Abstract: This contribution deals with the results of a recent study on stress development and risk of cracking in plain hardening concrete. The experiments are performed in a Temperature Stress Testing Machine (TSTM), developed for analysing the built-up of self-induced stresses in hardening concrete. Measurements of stress development started directly after setting of the concrete. The self-induced stresses originate from both the thermal strains and autogenous deformation (shrinkage, sometimes swelling). Different types of concrete and types of cement were considered, i.e. Portland cement and blast furnace slag cement. Mixtures were made with different water/binder ratios. Both isothermal tests and semi-adiabatic tests have been performed. A number of tests were performed at different degrees of restraint of the concrete. The test results, i.e. the observed stress/strength ratio at failure, will be presented and discussed. Based on the test results a criterion for cracking at early ages is developed. This criterion has been used as the basis for a design graph, with which the risk of (through-)cracking of plain concrete can be assessed. The risk of cracking is coupled with a traditional safety factor, and an allowable stress/strength ratio, to be adopted for practical design tasks.

Online publication: 2010-06-02
Publication type : full_text
Public price (Euros): 0.00