148 CEMENT AND CONCRETE 



Materials Needed: Enough cement, sand and gravel or broken 

 stone, and water to complete the job. For a 1 : 2 : 4 

 mixture, 1 sack of cement, 2 cubic feet of sand and 4 

 cubic feet of gravel should make 4-1/4 cubic feet of 



FlG. 148-a. Boys constructing sidewalk. 



concrete, or 13 square feet of walk or floor 4 inches 

 thick. Material for forms must also be provided 

 2 x 4's with suitable stakes are very satisfactory. 

 Preliminary Instructions: The general principles of proper 

 proportioning, mixing and placing should be carried 

 out in constructing sidewalks the same as in any other 

 type of concrete construction. In work of this class, a 

 quaky mixture should be adopted. A walk should 

 not be made by putting down coarse material and 

 pouring over it a cement-sand mortar. Because of 



