A construction member cracks, if stresses inside
of it become larger than the resistance of the
construction member. By cracking, the buildup
of stresses is relieved. In comparison to the
compressive strength, the tensile strength of
concrete is quite low. This applies especially to
fresh concrete. The most frequently encountered
cracks are therefore tensile cracks and compressive
tensile cracks. There are many reasons
which cause stresses in construction members.
In most cases however, it is a combination of the
following reasons: