Early thermal contraction cracking

Early thermal contraction cracking, also known as thermal stress cracking or curling, is caused by excess temperature gradients (deferential) or moisture content between the top and bottom of a slab, attributed to rapid cooling when ambient temperature drops and, in the case of thick (mass) concrete elements, to excess heat generation during hydration of the cement. 

The early thermal contraction cracks are linear and formed in the slab s corners or edges. The cracks may be deep and of variable length depending on the size of the concrete element. The typical time of appearance is after 1 day to 2-4 weeks. 

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Early thermal contraction cracking or thermal stress cracking... 

Early thermal contraction cracking - occurs within a few days of casting. 

Concrete structures often show cracks. There are several reasons for the formation of these cracks, including physical effects, drying shrinkage, crazing, thermal effects due to seasonal variations in external temperature, early thermal contraction, freeze-thaw cycles and structural effects such as overloading and impact (Concrete Society, 1982). 

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