XI, A, 1 King: Pozzuolanic Properties of Meycauayan Tuff 27 

 Table V. — Composition of limestone from Montalbayi. 



Per cent. 



Moisture 0.25 



Silica (SiO^) 0.94 



Ferric and aluminium oxides (FeaOa plus AlaOs) 1.14 



Calcium oxide (CaO) 54.61 



Magnesia (MgO) 0.22 



Loss on ignition 42.79 



The calcined product is white, with a slight yellowish tinge. 

 It slakes very rapidly and violently, evolving considerable heat. 

 When sufficient water is added to form a paste, the resulting 

 mass is very plastic and shows the characteristic properties of 

 a fat lime. For this investigation the quick lime was dry slaked 

 by sprinkling with just sufficient water to produce a fluffy, dry, 

 impalpable powder. The slaked powder was separated from 

 lumps of quicklime and the underburned material by sieving 

 through a 100-mesh sieve." The fine lime powder was very 

 white and showed the following composition : 



Table VI. — Composition of fine lime powder from lime made from MontaU 



ban limestone.^ 











Per cent. 



Silica (SiO,) 









0.58 



Aluminium oxide (AljOs) 









0.11 



Ferric oxide (FejOa) 









0.41 



Calciimi oxide (CaO) 









74.04 



Moisture 









23.56 



Carbon dioxide (CO2) 









0.30 



Magnesia (MgO) 









0.93 



Sodium and potassium oxides (K2O plus 



Na^O) 



0.30 



» Analysis by R. H. Aguilar, 



chemist, 



Bureau of Science. 



MIXTURES OF TUFF AND HYDRATED LIME 



Tests were carried out on three different mixtures containing 

 90, 75, and 50 per cent of tuff mixed with 10, 25, and 50 per 

 cent of hydrated lime, respectively. The tuff and lime were 

 weighed separately and mixed, for fifteen minutes, in a ball 

 mill. The mixes were designated as A, B, and C, respectively. 

 They had the appearance of ordinary Portland cement, except 

 the color was somewhat lighter; this difference in color was 

 more noticeable when the tuff mixtures were made up into 



" The resulting powder when placed in a metal drum preparatory to 

 incorporation with the tuff exhibited a property that very closely ap- 

 proached the flow of a liquid when the container was moved. This pheno- 

 menon is due to the film of air that surrounds the minute particles and 

 keeps them in suspension, thus reducing friction to a minimum. 



