290 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



tile, four inches of concrete is filled in. If the soil is firm, no 

 form will be needed below ground and above ground a circle 

 of tile may be laid up temporarily to make a form for the pro- 

 tecting concrete. In this way the use of expensive forms may 

 be dispensed with entirely. If it is found that the tile are fully 

 protected in this way, it will be best to lay them horizontally, 

 making the foundation as frost proof as any part of the 

 structure. 



The tile blocks, for walls, which may be of any of the com- 

 mon dimensions in use, are laid in a rich cement mortar. The 

 blocks are used 5 by 8 by 16 inches, but blocks 4 

 by 8 by 12 and 4 by 5 by 12 inches have been used successfully. 

 To make a smooth wall the blocks must be bent to the curvature 

 of the silo. Several manufacturers are now prepared to furnish 

 the bent blocks without great additional cost. 



The door frames are of concrete. The concrete is placed 

 at the ends of the tile of the wall, and though not shown, the 

 concrete extends back into the tile from 4 to 8 inches, bonding 

 the frame securely to the tile of the wall. The distance this runs 

 back into the wall depends upon the amount of tamping and the 

 amount of water in the concrete. 



Any one of several methods of reinforcement may be used 

 in the Iowa silo. The wire, which when purchased, 

 is received in coils, is drawn through a section of one 

 inch pipe bent sufficiently to straighten the wire until it takes the 

 curvature of the silo wall. If extending entirely around the silo, 

 the ends are lapped and bent so as to form a loop at the ends, 

 or if the reinforcement extends into the side of the door frame, 

 the loop is made to encircle the vertical reinforcement which 

 should be placed there. A one-half inch rod was used in the 

 experimental silo at each side of the doorway about two inches 

 from the surface. In using steel for reinforcing, it should all be 

 thoroughly protected from rust by imbedding it within the con- 

 crete. 



The Christensen system of reinforcement might be used to 

 good advantage or, in other words, tile blocks could be used 

 instead of brick in the Christensen silo. 



