Pore structure and freezing resistance of nanoclay modified cement based materials

Abstract

This paper presents a study of the effect of nanoclay on the freezing resistance behaviour of cement based materials. The pore structure in the cement pastes with the addition of nanoclay was examined through mercury intrusion porosimetry test. The influence of nanoclay addition on the frost resistance of cement mortar was intensively studied with freeze–thaw cycle test. The test results indicate that the addition of nanoclay refines the pore structure and reduces the porosity of cement paste. It was found that the most probable pore diameter, total specific pore volume and porosity of cement paste with 1% additive nanoclay decreased by 56·84, 22·58 and 18·48% respectively. The findings suggest that the addition of nanoclay will improve the frost resistance of cement mortar significantly. Compared to normal cement mortar, the reduction in weight loss was 55·88% and the improved compressive strength was 21·25% of cement mortar, with 1% additive nanoclay at 28 days curing age after 20 freeze–thaw cycles.