CLINKER COOLING, GRINDING, AND STORAGE. 



543 



Effect of calcium sulphate on strength of cement. In addition to 

 retarding the set of the cement, gypsum or plaster exerts an interesting 

 influence on its strength and, in some cases, its soundness. 



1.0 2.0 3.0 



PERCENTAGE OF PLASTER PARIS 



FIG. 138.* Effect of plaster on strength of 1:3 mortar. (Tetmajer.) 



TABLE 201. 



EFFECT OF CALCIUM SULPHATE ON STRENGTH OF CEMENT. (DYCKERHOFP.) 



* From Johnson's "Materials of Construction", p. 187. 



