early stiffening

false set, early stiffening, hesitation set, plaster set, premature stiffening, rubber set

The rapid development of rigidity in a freshly mixed portland cement paste, mortar, or concrete without the generation of much heat; this rigidity can be dispelled and plasticity regained by further mixing without addition of water.
References in periodicals archive ?
Loss of workability may be due to false set or early stiffening. Excessive calcium sulfate in the form of plaster in the cement results in false set whereas the uncontrolled early hydration of alluminates in the cementitious materials may cause early stiffening.
Early stiffening in the cement phase of concrete leads to loss of workability, as indicated by loss of slump.
The risk may be higher in concretes that exhibit early stiffening, as the mix does not remain fluid long enough to allow a layer of bleed water to remain on the surface.