132 The Philippine Journal of Science i9i4 



Table II. — Characteristics of the first four cement mixtures — Continued. 



PRINCIPAL ULTIMATE CONSTITUENTS AFTER VITRIFICATION (BY CALCULATION). 



Constituent. 



Silica (Si02) 



Alumina (AI2O3) 



Ferric oxide (Fe203) 



Calcium oxide (CaO) 



Magnesia (MgO) 



„ , ,. , , /%CaO+%MgO\ 



Hydraulic modulus! 4~r^ — , '-.Z^ 1 



V%Sl02 + %R203/ 



Mixture No. 



23.10 

 5.22 

 5.50 



63.60 

 1.43 



1.92 



23.90 

 3.14 

 3.05 



64.70 

 1.28 



2.15 



23.55 

 4.15 

 4.34 



62.50 

 1.57 



1.97 



23.00 

 4.87 

 3.76 



63.70 

 1.46 



2.10 



REFRACTORY PROPERTIES. 



Mix- 

 ture. 

 No. 



Observations. 



Easily sintered into well-burned clinker at a temperature considerably below the melting 



point, and no tendency of product to dust. 

 Similar to 1, but a little more refractory. 



Similar to 1, but if fused the clinker dusted completely while cooling. 

 Ideal refractory properties, and no tendency to dust when cooling. 



Throughout this work the various materials and products were 

 not ground to a greater degree of fineness than is customary 

 in commercial manufacture, although in most instances better 

 results could have been obtained by so doing. 



After the addition of sufficient water, each mixture was molded 

 into briquettes and burned practically without contamination 

 to the point of incipient fusion, the accepted product being anal- 

 ogous to well-burned rotary clinker. The clinkers were crushed 

 in a jaw crusher, mixed with 1 per cent plaster, and ground 

 by means of a tube mill employing manganese-iron balls, to 

 the degree of fineness demanded by our cement specifications. 

 The finished products were then subjected to preliminary tests 

 for soundness. 



As shown by the attached photographs in Plate I, all of the 

 steamed pats remained perfectly sound. They all adhered 

 firmly to the glass plates, and showed excellent color and texture. 

 As the cements had not been seasoned, their soundness proved 

 conclusively that the clinker had been well burned. Further- 

 more, observations during the process of burning showed that 

 the mixtures would meet the requirements of commercial kilns. 



