) Consolidation off the concrete is not sufficiently done. Insufficient consolidation may leave many entrapped air voids in the concrete. The evacuation of those air voids from the concrete results in settlement. However, over-consolidation causing segregation of the concrete must be avoided too.
4) Water absorption of the formwork is high.
5) Curing of concrete is not properly done so that water can evaporate much form the surface of the concrete or the concrete or the covering materials for curing concrete can absorb large amount of water from the concrete.
6) Relative humidity of the environment is low.
7) Deformation and movement of the formwork is excessive.