SHRINKAGE STRESS DEVELOPMENT IN CEMENTITIOUS MATERIALS

Author(s): Will Hansen, Eduard A.B. Koenders, Zhichao Liu, Bo Meng and Ya Wei
Book Title: RILEM International Symposium on Concrete Modelling - CONMOD 2014
Editor: Kefei Li, Peiyu Yan and Rongwei Yang
ISBN: 978-2-35158-139-1
e-ISBN: 978-2-35158-140-7
Publisher: RILEM Publications SARL
Publication year: 2015
Pages: 204-212
Total Pages: 9
Language: English

Abstract: The tensile modulus associated with viscoelastic (i.e. time-dependent) deformation is of major importance in stress analysis of concrete. This paper presents experimental evidence for the differentiation between Young’s modulus due to external loading and the viscoelastic modulus associated with internal loading from shrinkage stresses generated by selfdesiccation. Autogenous shrinkage deformation is the result of internal compressive stresses in the pores of cementitious reaction products. If this deformation is restrained a stress reversal develops. A comparison of free shrinkage and restrained shrinkage from steel reinforcement makes it possible to determine not only the tensile stress development from shrinkage restraint, but also the tensile modulus associated with shrinkage restraint. Stress analysis is simplified in this case since autogenous shrinkage creates a uniform stress distribution within a cross section as opposed to the analysis of drying shrinkage stresses. The shrinkage modulus was found to be a constant over time, averaging about 7,500 MPa. Thus, it is a unique material property on par with the Young’s modulus, which reflects the instant resistance to deformation of the concrete due to external loading (e.g. thermal and mechanical). Both internal and external moduli are needed for total stress analysis.

Online publication: 2015
Publication Type: full_text
Public price (Euros): 0.00