Frost damage can occur as cracks, stone splinters and swelling of the material.
[citation needed] When the volumetric moisture content exceeds 91 %, then the volume increase of water in the pores of the material caused by freezing cannot be absorbed by sufficient empty pores.
If this pressure exceeds the tensile strength of the material, then micro-cracks occur.
Visible frost damage develops after an accumulation of micro-cracks as a result of several freeze-thaw cycles.
[4] Therefore, when concreting at cold temperature cannot be avoided, it is essential to have a minimum curing time at a temperature sufficiently above the freezing point of the concrete pore water, so that the early strength of concrete is high enough to resist the inner tensile stress caused by water freezing.