i. 



THE MATERIALS AND MANUFACTURE OE PORT- 

 LAND CEMENT.* 



15Y Ei)\VIX ('. ECKEL. 



[The following paper on the raw materials and methods of manu- 

 facture of Portland Cement has been prepared as the result of field 

 work and other investigations carried out by the writer for the 

 United States Geological Survey. Certain sections of the contribu- 

 tion have appeared, in slightly different form, in Municipal Engi- 

 neering during the past two years.] 



CHAPTER 1. 



THE RELATION OE PORTLAND TO OTHER 

 CEMENTS. 



It seems desirable, before taking up the specific subject of 

 Portland cement, to indicate the relationships existing between 

 Portland and other cementing materials. These relationships, 

 both as regards resemblances and differences, seem to be best 

 brought out by the classification presented below. This group- 

 ing is based primarily upon the amount of chemical change 

 caused by the process of manufacture and use ; and secondarily 

 upon the chemical composition of the cement after setting. As 

 regard is paid to both technologic and commercial conside- 

 rations, it would seem to be a fairly satisfactory working classi- 

 fication. 



GROUP I. SIMPLE CEMENTS : Including all those cement- 

 ing materials produced by the expulsion of a liquid or gas from 

 the rarvv material ; and whose setting properties are due to the 



*Publishcd by permission of the Director, U. S. Geological Survey. 



