40 



Concrete Silos 



joints between the courses, a more difficult operation, 

 and giving less strength than where the rods are em- 

 bedded in the concrete, as in the case of monolithic 

 concrete work, or where they have special grooves 

 made to receive 

 them, as in the case 

 of concrete blocks, 

 or, again, where they 

 completely encircle 

 the silo, as in con- 

 crete stave construc- 

 tion. Bricks, too, 

 present flat surfaces 

 to each other, having 

 no bond except the 

 mortar joint which 

 connects them, while 

 concrete blocks made 

 especially for silo work usually have some device for 

 interlocking them in both directions, thus making them 

 stronger to withstand strains either from within or 

 without. And brick are open to the same objection as 

 stone in that they do not present a smooth interior 

 surface. 



With slight modifications, the same objections that 

 have been stated against brick will hold good as 

 against structural tile. The air space of the structural 

 tile will to a certain extent atone for its porosity; but 

 on the other hand it is more expensive than brick and 

 is even more difficult to secure, as it is made only in 

 widely separated plants. 



In view of the claim of the opponents of concrete 

 that it will be destroyed by the action of the acids in 

 silage, it is interesting to note the illustration here re- 



This Vitrified Tile Silo Collapsed First 



Night After Filling. On Farm of 



Neff Wildrick, Colusa, 111. 



