X-ray microtomography (μ-CT) to evaluate microstructure of mortars containing low density additions

The present paper examines the effect of expanded perlite, expanded glass and cenospheres on cement mortars porosity. The mortars were scanned using X-ray microtomography (μ-CT) and the reconstructed images were treated with the 3D analysis software Morpho+. The mortar microstructure was studied in terms of porosity (open, closed and partial porosity) and the equivalent diameter of the pores. Porosity was seen to vary greatly, depending on the low density addition and its internal structure. The lowest open porosity was obtained in mortars made with cenospheres, whereas expanded perlite provided the highest open porosity. Capillary water absorption tests carried out to validate the porosity data confirmed that the expanded perlite mortars had the highest absorption. When additional software for voxel data visualization and light microscopy were used to visualize the mortar microstructure, the digital images and thin sections obtained showed good adhesion between the studied additions and the cement paste.