110 



C = the volume of cement paste In a unit volume of 

 concrete. 



8 = volume of sand. 



G volume of stone or gravel. 



E percentage of excess, generally about 10%. 



a percentage of voids in stone or gravel. 



6 percentage of voids in sand. 



For a detailed discussion, see Buel & Hill, page 484. 

 This can be compared with William B. Fuller's formula 

 given in Taylor & Thompson. 



c number of parts of cement. 



8 number of parts of sand. 



g=z number of parts of gravel or broken stone. 



Then , , =./- > =number of barrels of cement per cu. yd. 



concrete. ' 



9 Q 



~~~ =numberof cu. yds. of sand per cu. yds concrete. 



o 



- yds. * stone per cu. yds concrete 



Materials for One Cubie Yard of Concrete. 



The following suggestions are taken from a pamphlet 

 Issued by the Marquette Portland Cement Co.: 



Character of Materials to be Used with Cement: Sand 

 should be clean, coarse and share. A loamy sand should 

 not be used; it will give bad results and retard the set. 

 A very fine sand or gravel should be avoided; it will 

 weaken the work. Gravel should be clean and vary from 

 V4 in. to 2 in. in size. Care must be taken, if work is 

 being done in winter time, that the material is kept from 

 freezing, and that warm water is used, instead of cold, 

 for mixing concrete. Orushed stone should be clean and 

 free from dust or dirt. 



