CHAPTER XVIII. 



CONCRETE CONSTRUCTION. 



Concrete, or artificial stone, is a mixture of gravel oi 

 crushed stone, sand, and Portland cement. When properly 

 executed concrete forms a permanent and comparatively 

 inexpensive material for the construction of foundations, 

 steps, sidewalks, cellar and farm building floors, feeding 

 areas, cisterns, watering and feeding troughs, fence and 

 hitching posts, horse blocks, piers, culverts, building 

 blocks, building walls, etc. 



The crushed stone or gravel and sand should be rea- 

 sonably free from clay^ and loam. The sand should not 

 be too fine. Except for the most unimportant work the 

 cement should be of the best grade. Cement may be pur- 

 chased in sacks of one-fourth barrel each, weighing 

 a little less than 100 pounds. Walks and floors should 

 be subdrained and should have a slope of 1 inch in 4 feet 

 for surface drainage. Where freezing will occur walks 

 should be underlaid with from 4 inches to 12 inches of 

 cinders, gravel, or broken stone, well wetted and very 

 thoroughly tamped. Foundations, piers, etc., should 

 extend well below the frost line. 



851. How many cubic yards of concrete are required 

 in the construction of a cellar floor 12 feet by 20 feet and 

 1 inches thick? Three inches thick? 



Process: 



12 X 20 = 240 Square feet in area of floor. 



240 Xl/3= 80 Cubic feet in volume of concrete. 



80 H- 27 = 3 Cubic yards in the 4-inch floor. 



852. How many cubic yards would be required for 

 three 3-inch floors, 8 feet by 12 feet, 16 feet by 32 feet, 

 and 10 feet by 14 feet, respectively? 



2;jo 



