P ACINI, METAMORPHISM OF PORTLAND CEMENT 



199 



than the corresponding neat cement mixes, and the following series of 

 compressive tests was made : 



TABLE 11 



Effect of Clay upon Destructive Action of Eacess of Mixing Water 

 (Average of two tests at 28 days) 



If the action of saline solutions upon cement is to accelerate the hy- 

 drolysis of the latter, it would appear that the destructive action of excess 

 water would be accelerated by the presence therein of saline substances 

 in solution; also, it is legitimate to expect that the addition of clay 

 restraining the hydrolysis due to excess water will in this case exert a. 

 similar influence. 



The following experiments, parallel to the foregoing ones, elaborate 

 this point: 



TABLE 12 



Effect of Clay upon accelerated destructive Action of Mixing Water Containing 

 5 per cent of Magnesium Sulphate 



(Average of two tests at 28 days) 



