THE EFFICIENCY OF PORTLAND CEMENT RAW MATERIALS 



FROM NAGA, CEBU 



By W. C. Reibling and F. D. Reyes 



(From the Laboratory of General, Inorganic, and Physical Chemistry, 



Bureau of Science, Manila, P. I.) 



Two plates 



INTRODUCTION 



In the interest of certain prospective manufacturers, the most 

 promising of the raw materials from Naga, Cebu, were collected 

 by Mr. Wallace E. Pratt, a geologist of the Bureau of Science, and 

 submitted to as comprehensive an investigation as was necessary 

 definitely to establish the relative merits and suitability for the 

 commercial manufacture of Portland cement. Before presenting 

 our experimental work, we shall discuss a few considerations 

 which appear to be generally misunderstood or overlooked. 



Most of the materials had already been tested by two laborato- 

 ries in the United States, and they reported results which, with 

 a few exceptions, were satisfactory. However, the few un- 

 satisfactory features involved considerations of such vital im- 

 portance that the prospective manufacturers could not accept 

 the data obtained as sufficient evidence to justify further steps 

 toward the establishment of a plant. Finally, they submitted 

 the reports to the Bureau of Science, and requested our inter- 

 pretation of their significance. 



The laboratories in question did the work which they were 

 requested and paid to do in a very honest and painstaking man- 

 ner, and while we criticize certain of their methods and con- 

 clusions this is not done in an attempt to cast reflections on their 

 work and reputation. Their methods compare favorably with 

 those of most laboratories, and their conclusions are based upon 

 generally accepted theories and practices, some of which are 

 of doubtful value. We shall make specific reference to their 

 reports, because their data stand as official records against many 

 of our own conclusions on the merits of these raw materials. 



We fail to find much significance or usefulness in results 



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