94 



The Philippine Journal of Science 



1914 



The ground clinker from the burned mixture gave the follow- 

 ing results: 



Table X. — Physical examination of cement from volcanic tuff raw mixture 

 containing 2.29 per cent less pure limestone than required by the 

 formula. 



Fineness. 



Specific 

 gravity. 



Soundness. 



Initial set. 



Final set. 



Tensile strength in pounds 

 per square inch. 



200 

 mesh. 



100 

 mesh. 



5 hours. 



28 days. 



Neat cement. 



1 cement: 

 3 sand. 



"J»y- da^s. 



7 days. 



28 

 days. 



89.6 



99.8 



3.19 



Sound -. 



Sound .. 



Hrs. min. 

 55 



Hrs. min. 

 1 15 



776 



800 



370 



437 



Table XI. — Calculation of volcanic tuff raw mixture containing 5.22 per 

 cent less pure limestone than required by the formula. 





Total. 



» Individual constituents. 



Silica 

 (SiOz). 



Alumina ^'"P? 



1 



i 

 Lime Magnesia 

 (CaO). (MgO). 



i 



Volatile 



(CO2, H2O. 



etc.). 



Figures represent parts of the material by 



weight. 





Limestone 



Tuflf 



Unburned 



Volatile _. 



Burned 



281.40 

 100.00 









156.63 

 4.31 





123.77 ■ 

 9.30 



56.36 



19.53 



6.97 



1.70 



381.30 

 133.07 



56.36 1 19.53! 6.97 



t 



161. 84 ! 1. 70 



1 



133.07 



" " " 1 



248.23 56.36 19.53 ' 6.97 



1 ! 



161.84 ^ 1.70 









Calculated composition in percentage. 





Mixture 



Clinker 



99.48 14.78 5.12 1.83 

 99.26 I 22.71 7.87 1 2.81 



42.43 

 65.19 



0.44 

 0.68 



34.88 













The silica to alumina (plus iron oxide) ratio in the mixture is 2.13. 

 The lime to silica, alumina, and iron oxide ratio in the mixture is 1.95. 

 The cementation index of the mixture is 1.12. 



The ground clinker from the burned mixture gave the following 

 results : 



