PHYSICAL PROPERTIES OF PORTLAND CEMENT. 



595 



2500 



2000 



Q 1000 



< 



o 



500 



\ 



TENSION 



\ 



\ 



20 15 



PERCENTAGE= 



10 5* 



CEMENT 



TOTALSAND AND CEMENT 



FIG. 151.* Strength of sand-cement mortar with varying proportions of sand. 



400 





200 



100 



-TENSION- 



FIG. 152.f Variation in strength of sand-cement mortar when the total proportion 

 of sand is constant, but the relative proportions of ground and unground sand 

 are variable. 



* From Johnson's " Materials of Construction", p. 580. 



t Ibid., p. 581 



