Use of confocal microscopy to measure the porosity of cement containing sulfocalcic binder: A comparative study

This work proposes an effective methodology for measuring the porosity of mixed hydraulic binders applying image analysis (IA) with confocal microscopy (CM). CM offers a certain simplification of sample preparation compared to the standard procedure EN 480-11, as the steps of sample staining and pore masking are eliminated. A set of cement and a hydraulic clinker-free sulfocalcic binder pastes was prepared with various aeration. Total air content, micro air content and the air pore spacing factor according to EN 480-11 standard were determined for hardened pastes using measuring chords. Subsequently, a new simple Surface porosity evaluation for IA methodology using CM was proposed and results were compared with the standard evaluation. The results of both IA evaluations achieved high agreement and the new porosity Surface evaluation was found to be promising for the determination of total air content. Porosity values measured by both IA methods were further compared with MIP.