136 



The Philippine Journal of Science 



1914 



The data in Table V show that in this second series of tests 

 the calculated percentage of calcium oxide was reduced from 

 63.60 in mixture 1 to 62.23 in mixture la and from 64.70 in 

 mixture 2 to 63.00 in mixture 2a and was increased from 62.50 

 in mixture 3 to 64.40 in mixture 3a. The object of making 

 these modifications has already been stated in the introduction, 

 and the necessity of it will be verified in the discussion of 

 the results obtained. 



The essential characteristics of the nonseasoned cements 

 obtained from well-burned clinkers of these mixtures are given 

 in Table VI. 



Table VI. — Characteristics of nonseasoned cements obtained from the second 



series of mixtures. 



Test. 



Mixtnre No. 









1 





5. 



la. 

 Per cent. 



2a. 



3a. ' 



Fineness: 



Per cent. 



Per cent. 



Pej- cent. 



Through the 100-mesh sieve 



97.4 



98.4 



98.4 



94.8 



Through the 200-me3h sieve 



86.7 



77.8 



76.4 



75.8 



Soundness, in air, water, and steam.- 



sound 



sound 



sound 



sound' 



SETTING PROPEETIES. 



Mixture 

 No. 



Plaster 

 added. 



Water 

 required 

 for nor- 

 mal con- 

 sistency. 



Initial 

 set. 



Final set. 





Per cent. 



Per cent. 



Hrs. min. 



Hrs. min. 



5 



1 



21 



1 



3 



la 



1 



21 



45 



6 15 



2a 



1 



25 



Flash set." 



3a 



1 



27 



Flash set.a 



5 



2 



20 



2 20 



4 20 



la 



2 



20 



2 55 



5 55 



2a 



2 



21 



30 



1 45 



3a 



2 



21 



2 35 



5 35 



' See note to Table III. 



Experiments on the setting properties of No. 2a showed that 

 the compounds which caused the cement to set were so active and 

 abundant that 3 per cent of plaster and twenty-four hours of 

 thorough aeration were required to produce satisfactory results. 

 The physical properties of No. 2a treated in this manner, and 

 of cements 5, la, and 3a, mixed with 2 per cent of plaster 

 and aerated one day, are given in Table VII. 



