Exploring the potential of X-ray tomography in microstructural studies of cementitious systems

Title: Exploring the potential of X-ray tomography in microstructural studies of cementitious systems
Author(s): V. Boel, V. Cnudde, G. De Schutter, P. Jacobs
Paper category : conference
Book title: 2nd International RILEM Symposium on Advances in Concrete through Science and Engineering
Editor(s): J. Marchand, B. Bissonnette, R. Gagné, M. Jolin and F. Paradis
Print-ISBN: 2-35158-003-6
e-ISBN: 2351580028
Publisher: RILEM Publications SARL
Publication year: 2006
Nb references: 9
Language: English

Abstract: Durability of cementitious systems is to a large extent depending on the transport of potentially aggressive substances within the microstructure of the material. A fundamental evaluation of durability on the ‘engineering level’ should thus be realised by investigating the microstructure on the ‘materials science level’.
Traditionally, mercury intrusion porosimetry (MIP) is giving very valuable results concerning the pore system of cementitious material. However, it is not a direct visual method, and shows some major drawbacks due to problems related to the basic assumptions made for the interpretation of the results. Based on MIP results, it is very difficult to validate advanced numerical simulation methods devoted to the description of the microstructural properties.
A more direct, visual investigation of the pore system of cementitious materials can be realised by means of X-ray tomography. X-ray computed tomography (CT) provides non-destructive three-dimensional visualisation, creating images that map the variation of X-ray attenuation within objects. The X-ray transmission through an object is function of the material composition (effective atomic number), density and thickness. X-ray tomography produces a stack of 2D-shadow images of complete internal 3D-structures by reconstructing a matrix of X-ray attenuation coefficients. These images can then be volume-rendered to provide 3D-information.
This contribution focuses on the possibilities of X-ray CT applied on cementitious systems. Interesting images of the air-void system can be obtained using micro-tomography, with a resolution of about 10 microns. However, for a better view of the microstructure, CT-scans with higher resolution have to be realised, using nano-tomography.

Keywords: air voids, microcracks, X-ray tomography, 3D visualization

Online publication: 2006-08-02
Classification: 3.1 Theme 1: Numerical Models: from Microstructure to Transport Properties and Durability
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580028.018