Earthmover...concrete is at its maximum volume just after placement. From that point onward, it continues to shrink. Thermal expansion can rarely overcome that shrinkage. This usually only occurs in long, thin strips (sidewalks, pavements, etc.) that have other actions working as well, such as impacted joints (debris, etc. fills the joint space), moisture expansion, etc.
As JAE noted, shrinkage cracks only develop from restraint. Unfortunately, almost all concrete placements have some restraint, either from friction at the subgrade interface or from geometry. In general, expansion does not cause cracking. If expansion is extensive, heaving of thin sections can occur, or in drastic cases, shearing will occur at joints in thick sections.
See FAQ in Concrete Engineering Forum for additional info.