IX, A, 2 Reibling and Reyes: Portland Cement Materials 133 



The briquettes vitrified at a comparatively low temperature, 

 slightly lower than the raw meal used for the manufacture of 

 "Green Island" Portland cemfent, but sustained such a consider- 

 able increase in temperature without fusing that no difficulty 

 was experienced in producing good, thoroughly sintered clinker 

 without melting part of the charge. There also was practically 

 no "dusting" when the well-sintered, uncontaminated clinker 

 cooled. 



We were prepared to make a thorough study of the setting 

 properties of these cements under different conditions of season- 

 ing, grinding, and plastering, but a few tests showed that there 

 need be no difficulty in controlling their setting properties and 

 that the amount of plaster or gypsum required could be 

 maintained at a low figure. 



The results obtained with the nonseasoned cement are recorded 

 in Table III. 



Table III. — Essential characteristics of the nonseasoned cements produced 



from the first four mixtures. 



Test. 



Mixture No. 



1. 



2. 



3. 



4. 



Fineness: 



Through the 100-mesh sieve- _ _- 



Per cent. 



98.8 



79.4 



sound 



Per cent. 



97.8 



77.6 



sound 



Per cent. 



98.2 



77.8 



sound 



Per cent. 

 97.8 

 77.6 

 sound 



Through the 200-rae9h sieve 



Soundness, 5-hour steam test 





Setting properties. 







Water re- 







Mixture 

 No. 



Plaster 

 added. 



quired 

 for nor- 

 mal con- 

 sistency. 



Initial 



set. 



Final set. 





Per cent. 



Per cent. 



Hrs. min. 



Hrs .min. 



1 



1 



21 



3 00 



5 55 



2 



1 



22 



1 10 



6 10 



3 



1 



a 27 



Flash set. " | 



4 



1 



21 



35 



5 25 



1 



2 



20.5 



2 30 



5 00 



2 



2 



21 



3 50 



5 50 



3 



2 



21 



1 30 



5 30 



4 



2 



20 



3 00 



5 00 



" The set was almost instantaneous, but when the cement was manipulated according to 

 specification an extremely slow-setting paste resulted which, in reality, was a regauged 

 cement. [Cf. This Journal, Sec. A (1911), S. 207-252.] 



