CEMENT BLOCK SILOS. 



95 



Fig. 37. Illustrates a type of concrete block used in silo 

 construction. H H are holes left in blocks. T and M 

 are dove -tailed tenon and mortise so made that blocks 

 interlock when laid on the wall. G is a groove made in 

 block to imbed iron rod for reinforcing the wall. 



Courtesy Wisconsin Experiment Station. 



The Nebraska Station has designed a special machine for 

 making these two-piece blocks and also a machine which will 

 make the single piece hollow block as shown in "c," Figure 35. 

 This block cannot be made as fast as the two-piece block but 

 is much easier to lay. It gives the troweled surface inside but 

 not outside nor does it give as perfect a dead-air space. 



Fig. 38. This form of block requires less material and does 

 not freeze so readily as the solid block. Note manner 

 of reinforcing by %-in. iron binders. 



Commercial blocks like "d" Figure 35 are very common. They 

 may be either straight or curved to fit the curvature of the silo. 

 Being generally very porous they should be plastered on the 

 inside after being put into the wall. Curved blocks require less 

 plaster but plaster must be used anyway and a straight block 

 not exceeding 16 inches in length will make a good silo. The 

 usual dimensions of curved blocks are 8x8x16 or 24 inches. 



Cement blocks are usually made of finer materials than are 

 the solid monolithic walls. The blocks are made of sand and 

 cement; or if any gravel is used it is very fine gravel whereas, 

 in the continuous wall monolithic construction, coarser gravel or 



