Ultrahigh-performance concrete: Material engineering by nanoindentation testing and nanomechanical analysis

Title: Ultrahigh-performance concrete: Material engineering by nanoindentation testing and nanomechanical analysis
Author(s): Paul Acker
Paper category : conference
Book title: NICOM 2: 2nd International Symposium on Nanotechnology in Construction
Editor(s): Y. de Miguel, A. Porro and P.J.M. Bartos
Print-ISBN: 2-912143-87-X
e-ISBN: 2912143888
Publisher: RILEM Publications SARL
Publication year: 2006
Pages: 257 - 267
Total Pages: 11
Nb references: 15
Language: English

Abstract: Engineering of cement-based materials and optimization and fine-tuning of the final properties can now be improved and accelerated by nanoindentation testing. Nanotechnologies and more particularly nanosensors allow us to assess in vivo the physical (micromechanical) properties on smaller scales than the scale of the elementary particles that make up this kind of composite material (clinker phases, Portlandite, C-S-H gel).
Indentation tests made on Ductal®, [a non-brittle, fiber-reinforced, ultrahigh-performance concrete (UHPFRC)] at such a nanometric scale clearly shows that only the C•S•H phase presents a viscous strain (creep). This result explains the strong correlation observed between shrinkage and creep features: as soon as the hydration rate drops (usually after a few days), most of the shrinkage strain is nothing but the C•S•H’s viscoplastic response to the capillary forces applied by the water to the pore surface.
Creep ageing, as well as the very low creep in high-strength concrete can be explained by consumption of a potential creep strain due to the shrinking process. It is now possible to forecast and quantify the macroscopic properties of cement-based materials using Micromechanics and advance up-scaling schemes with the intrinsic properties of each of the composite material’s micro components directly.

Online publication: 2005-11-17
Publication type : full_text
Public price (Euros): 0.00