Spalling of HPC evaluated by acoustic emission and numerical analysis

Title: Spalling of HPC evaluated by acoustic emission and numerical analysis
Author(s): C. Grosse, R. Richter, J. Ozbolt, F. Dehn, M. Juknat
Paper category : conference
Book title: 2nd International RILEM Workshop on Concrete Spalling due to Fire Exposure
Editor(s): E.A.B. Koenders and F. Dehn
ISBN: 978-2-35158-118-6
e-ISBN: 978-2-35158-119-3
Publisher: RILEM Publications SARL
Publication year: 2011
Pages: 157 - 163
Total Pages: 7
Nb references: 5
Language: English

Abstract: High performance concrete (HPC) is often used in for columns of high raise buildings and similar structures which require high compressive strength. However, when exposed to high temperature (fire) there is a strong degradation of mechanical properties of HPC and it shows unfavourable behaviour i.e., explosive spalling of concrete cover. In the here described experiments the behaviour of concrete specimens that were exposed to fire is monitored by acoustic emission (AE) techniques. With these techniques damage processes in concrete can be observed during the entire fire history, including the initialization of explosive spalling.
The method enables the localization and characterization of micro-cracking before failure.
The proposed concept and preliminary results of fire experiments on concrete specimens made of high performance concrete are described. To support experimental results it is also important to have a numerical model which is able to realistically predict the behaviour of concrete at high temperature. Therefore, a fully coupled thermo-hydro-mechanical model for concrete was implemented into a 3D finite element code. The application of the model demonstrates that the pore pressure in combination with thermally induced stresses can lead to explosive spalling of concrete cover. Detailed descriptions of the numerical simulation and their results are presented by the authors from the University of Stuttgart in another paper submitted to this workshop.

Online publication: 2012-01-17
Publication type : full_text
Public price (Euros): 0.00