Shrinkage Eigenstress and Hardening of Concrete
Title: Shrinkage Eigenstress and Hardening of Concrete
Author(s): P. Paulini
Paper category : conference
Book title: International RILEM Conference on Material Science
Editor(s): W. Brameshuber
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 199 - 207
Total Pages: 9
Nb references: 14
Abstract: Hardening processes are always accompanied by eigenstresses. Thermal hardening reactions from molten states as well as chemical hardening reactions occur along adiabatic paths with irreversible changes of state. During hardening a bonding energy is supplied to the system and a reverse exothermic energy is released from the reacting system. Isotropic material hardening can be defined according to the specific volume strain energy based on the shrinkage volume.
The hydration of cement is accompanied by significant chemical volume shrinkage. The volume change of hydrating cement or concrete can be measured with buoyancy methods. Not only the chemical composition but also the potential of chemical shrinkage of cement is influenced by the early reaction (admixtures, temperature etc.) and by the fineness of the cement. An extrapolation to final values of chemical shrinkage of cements requires measurement periods of at least 10 to 14 days.
Ultrasonic velocity data permit access to increasing stiffness properties and can be obtained in simultaneously to buoyancy weighing measurements. The Poisson ratio, which changes from 0.5 in the fluid state towards its elastic final value, is a basic indicator for hardening.
Online publication: 2010-12-02
Publication type : full_text
Public price (Euros): 0.00