Mechanical performance of frozen hardened cement paste

The variations of compressive and bending strength of hardened cement paste under different freezing conditions were experimentally investigated. It is shown that the strengths for frozen pastes are increased in relation to unfrozen ones. The increment of the strengths is raised with increasing the content of freezable water and decreasing freezing temperature. The mechanism for the strength increment is discussed, and results indicate that micro-cracks and holes are filled with ice formed during freezing, causing the increase of strength. Conclusions provide certain basis for the study of the frost mechanism.