IX, A. 1 West and Cox: Philippine Cement Raw Materials 99 



respectively, were prepared. The calculation of these are given 

 in Tables XVIII and XX, respectively. ^^ 



Table XVIII. — Calculation of volcanic tuff raw mixture containing 5 per 

 cent less Binangonan limestone than required by the formula. 





Total. 



Individual constituentB. 



Silica 

 (Si02). 



Alumina 

 (AkOs). 



Iron oxide 

 (Fe208). 



^oxidT Magnesia 

 (CaO). (MgO). 



1 



Volatile 



(C02, H2O, 



etc.). 



The numbers give parts of the materials by weight. 





331.50 

 100.00 



7.72 

 56.36 



1.46 

 19.53 



1.29 

 6.97 



177.00 

 4.30 



2.46 



1.70 



1 



141. 40 

 9.30 



Tuff 



Un burned 



431.60 

 150.70 



64.08 



20.99 



8.26 



181.30 



4.15 



160. 70 



Volatile -. 

















280. 80 



64.08 



20.99 



8.26 



181.30 



4.15 









Calculated composition in per cent. 



Mixture 



99.62 

 99.28 



1 

 14. 85 4. 86 1. 91 

 22.82 7.47 ! 2.94 



42.02 

 64.57 



0.06 

 1.48 



34.92 



Clinker -. 

















The silica to alumina (plus iron oxide) ratio in the mixture is 2.19. 

 The lime to silica, alumina, and iron oxide ratio in the mixture is 1.94. 

 The cementation index of the mixture is 1.11. 



The ground clinker from the burned mixture gave the following 

 results : 



Table XIX. — Physical examination of cement from volcanic tuff raw 

 mixture containing 5 per cent less San Guillermo, Binangonan, lime- 

 stone than required by the formula. 



Tensile strength in pounds per 

 square inch. 



1 



Neat. 



Mortar 1 : 3. 



7 days. 28 days. 



7 days. 



28 days. 



i 



562 660 



359 



546 



" Even in the most uniform quarries, the raw materials will vary in 

 composition from time to time and the relative proportions of cement raw 

 mixture must be rea>djusted. When a constant value for the percentage 

 of lime in the mixture has been chosen, the adjustment can be readily 

 accomplished by arranging a table with the limits of the percentage of 

 lime in the limestone and siliceous cement materials, respectively, as abscissa 

 and ordinate, so that when the percentages are known the combining pro- 

 portion to give a mixture with a fixed lime content can be at once read 

 by noting the point of intersection of the corresponding coordirtates. 



