CHARACTERISING THE PORE STRUCTURE OF CEMENT-BASED MATERIALS USING BACKSCATTERED ELECTRON AND CONFOCAL MICROSCOPY

Abstract

The pore structure of cement-based materials affects their mechanical properties, shrinkage behaviour, molecular/ionic transport properties and durability. This paper presents an overview of our work on imaging of capillary pores in cement-based materials using 2D backscattered electron microscopy and 3D laser scanning confocal microscopy. Our aim is to develop an integrated imaging approach that is able to provide relevant parameters of the pore structure that can be used as input values to transport prediction models. Topics covered in this paper include sample preparation, the importance of epoxy penetration and its relevance to patch microstructure, application of Monte-Carlo methods to simulate electron-solid interactions in cement-based materials, development of image analysis tools for accurate pore segmentation and for obtaining microstructural gradients at interfaces, and preliminary results on transport prediction using data obtained from 2D image analysis. The applicability of laser scanning confocal microscopy for 3D imaging of pores at sub-micron resolution and evidence for interconnectivity of Hadley grains with capillary pores are presented.