MASONRY 315 



Fuller's Rule for Quantities. If c is the number of parts of 

 cement; s, the number of parts of sand; g, the number of parts 

 of gravel or broken stone; C, the number of barrels of Portland 

 cement required for 1 cu. yd. of concrete; S, the number of 

 cubic yards of sand required for 1 cu. yd. of concrete; and G, 

 the number of cubic yards of stone or gravel required for 1 cu. 

 yd. of concrete. Then, 



' = c+s+g 



and G = Cg 



If the broken stone is of uniformly large size with no smaller 

 stone in it, the voids will be greater than if the stone is graded. 

 Therefore, 5% must be added to each value found by the pre- 

 ceding formulas. 



EXAMPLE. If a 1-24 mixture be considered, what will be: 

 (a) the number of barrels of cement, (&) the number of cubic 

 yards of sand, and (c) the number of cubic yards of stone 

 required for 1 cu. yd. of concrete? 



SOLUTION. (a) Here, c=l, s = 2, and g = 4. Substituting 

 these values in the formula for C, 



(&) Substituting the values of C and s in the formula for S, 

 = .44 



(c) Substituting the values of C and g in the formula for G, 



3.8 

 G = X1.57X4 = .88 



Table of Concrete Quantities. The following table, which 

 gives the quantities of ingredients for concrete of various pro- 

 portions, has been prepared by Edwin Thacher. As will be 

 observed, he takes into account the difference in the character 

 and size of the stone or gravel used. 



