CONCRETE CONSTRUCTION 



251 



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Filling the Forms. In filling the form the 

 concrete is placed in layers about 6 inches 

 deep and tamped lightly until water shows 

 on the surface. This will 

 insure its settling together 

 closely- If the wall is not 

 to be plastered and a smooth 

 surface is required, a spade 

 or paddle is run down all 

 along between the concrete 

 and the sides of the form 

 when the concrete is poured. 

 This will force the larger 

 stones toward the center of 

 the wall and allow the 

 smaller stones and sand to 

 fill in next to the form, thus 

 making a smooth surface. 



Reinforcing. Concrete 

 will withstand enormous 

 crushing loads, but in walls where there 

 is a considerable side strain, it should be 

 reinforced with iron or steel. The best 

 materials for this purpose are iron or steel 

 rods. If they are twisted or roughened in 

 some manner, so that the concrete will ad- 

 here to them tightly, their efficiency will be 

 greatly increased. They are put in the 



89 



Fig. 129. Meth- 

 od of facing a 

 concrete wall 



