CHAPTER VIII 1 



CONCRETE 



Concrete. Concrete is an artificial stone made by the 

 mixture of cement, aggregate, and water. Its use in all 

 lines of construction requires that some knowledge of this 

 material, with the methods of using it, should be under- 

 stood by everyone. Improper selection or use of materials 

 and improper curing may result in poor construction or 

 rapid deterioration. 



TERMS AND DEFINITIONS 



The following terms frequently occur in literature on 

 cement, and their meaning should be clearly understood: 



Bank-run gravel. Gravel mixed with sand as found in 

 the natural bank. 



Bond. The foreje with which concrete grips or holds to 

 any foreign material. 



Batch. The quantity of concrete mixed at one operation. 



Cement matrix. That part of concrete formed by the 

 cement and water. 



Cement mortar. Cement mortar is a mixture of cement 

 sand, and water. 



Consistency. The relative quantity of water held by the 

 concrete. 



Initial set. The first hardening of the cement mixture, 

 usually taking place about thirty minutes after water is 

 added. 



Lean mixture. One containing a comparatively small 

 quantity of cement. 



Neat cement. Neat cement is a paste made by the 

 mixture of cement and water without any other material. 



1 After E. C. Crane, University of Minnesota, General Series Bulletin No. 52. 



129 



