PREFACE. 



OF all the non-metallic structural materials in use by the engineer, 

 the most important at the present day are those included under the 

 head of Cementing Materials, using that term in its broadest sense to 

 include not only the hydraulic cements proper, but the limes, plasters, 

 and allied materials. This importance is due in large part to the 

 advances which have been made, in American practice, in the methods 

 of manufacturing these products, for these advances in technology 

 have resulted in supplying the engineer with uniform and high-grade^ 

 cementing materials at prices low enough to permit of great increase^ 

 in their uses. 



In consequence of this growth of the industries based on cementing 

 materials an extensive literature on the subject has developed. This 

 literature is, however, widely scattered through the pages of many 

 technical and scientific journals and transactions, and no adequate' 

 summary of the matter from an American point of view has yet 

 appeared. The present volume is the result of an attempt to provide 

 such a summary, covering the composition and character of the raw 

 materials, the methods of manufacture, and the properties of the vari- 

 ous cementing materials. 



In a work of this scope many points of interest can only be sug- 

 gested, not discussed in detail. For the convenience of those who 

 wish to make further studies of such subjects, very complete reference 

 lists have been placed in almost every chapter of this volume. These 

 lists necessarily contain the names of some papers and articles pub- 

 lished in European periodicals or transactions, but most of the titles 

 cited will be found to be from readily accessible American journals. 

 A working engineer rarely has at his command an extensive technical 

 library, so that references to the proceedings of some German scientific: 

 society are apt to prove a vexation rather than an aid. 



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