crazing1             crazing
[1]                                              [2]

Crazing describes the development of a network of fine surface cracks due to rapid shrinkage of the surface layer relative to the underlying concrete [a]. Crazing cracks are typically less than 1/8th inch in depth and do not affect the structural integrity or serviceability of the concrete, but are a significant detriment to the aesthetic quality [b].

Crazing is prone to occur when new pours are exposed to high temperature, low humidity, or high winds that lead the surface layer to shrink faster than the underlying concrete [b]. Furthermore, overfloating or finishing the concrete while bleed water is present on the surface increases the water to cement ratio in the surface layer, therefore, decreasing the strength of the surface paste, making it susceptible to surface cracking [b].

When high evaporative conditions exist, crazing can be prevented by maintaining proper curing techniques. Begin curing as soon as finishing is complete by keeping the surface layer moist for 3 to 7 days [a]Curing can be maintained by either flooding the surface or covering with wet burlap [b].