Influence of alkali content on creep and shrinkage of cement-based materials

Title: Influence of alkali content on creep and shrinkage of cement-based materials
Author(s): F. Beltzung, F.H. Wittmann, X. Wan
Paper category : conference
Book title: International Conference on Microstructure Related Durability of Cementitious Composites
Editor(s): W. Sun, K. van Breugel, C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-065-3
e-ISBN: 978-2-35158-084-4
Publisher: RILEM Publications
Publication year: 2008
Pages: 905 - 915
Total Pages: 11
Nb references: 23
Language: English

Abstract: Hydration products of Portland cement and in particular C-S-H nano-particles are formed in an aqueous solution. When the density of particles becomes high enough at early age a solid skeleton is built up. The nano-particles are hindered to get in close contact by the disjoining pressure of intermediate water layers, but they are linked to each other by isolated electrostatic bonds and ionic correlation forces. This complex interaction between the pore liquid and the nano-particles of the hydration products is the origin of characteristic properties of cement-based materials such as strength, elastic modulus, creep and shrinkage. A change of alkali ion concentration of the pore solution results in a modification of the cohesion and the equilibrium distance. Ample evidence of the influence of the modification of the microstructure of cement-based materials by variation of alkali content on their properties has been provided in the past. In this contribution it will be shown that both creep and shrinkage depend also on the alkali concentration. A colloidal model is presented, which allows us to explain recent experimental results.

Online publication: 2009-06-09
Publication type : full_text
Public price (Euros): 0.00

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