Flash Set

-DUe to insufficient of the gypsum to control the rapid reaction of C3A with water .

-Is a rapid development of rigidity in freshly mixed cement paste .mortar or concrete
-Further mixing can;t dispel this rigidity , and a large amount of heat is prodiced in the process
- Can be overcome by adding more water and reagitating the mix . However , concrete strength will be reduced

False set

-ALso produces a rapid stiffering of the paste but is not accompanished bt exccesive heat
-Abnormal premature sttiffening of cement within a fewminutes of mixing with water .
-Remixing the paste without adding water to regain ts lasticity and its subsequent setting and hardening
-The results of intergiding gypsum with very hot clinker in the final stages of cement production .