CEMENT BLOCKS. 



127 



Cement Blocks. 



Continuing, the Bulletin just mentioned has the follow- 

 ing regarding cement block silos: 



Cement blocks are now made in a great variety of 

 forms and these are being used to some extent in silo con- 

 struction. Walls built of cement blocks, however, are not 

 so strong as are walls in which the concrete is built in 

 place, making what is known as a monolithic structure. 

 When cement blocks are used it is necessary to use bands 

 or rods in the wall laying them between the courses the 

 same as in the stone or brick construction. 



Cement blocks to be used in silo construction are 

 usually made with curved sides, the curvature being that 

 of the silo in question. A common type of block for this 

 purpose is illustrated in Fig. 39. The blocks are made 

 hollow, holes being left at H and H. The blocks are made 

 with a dovetailed tenon at one end, as at T, and a dove- 

 tailed mortise at the other end, as at M, BO that when 

 the blocks are laid on the wall they interlock. The blocks 

 are sometimes made with a small groove near the outside 

 edge as G, G, and on every third or fourth course a small 



Fig. 39. 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. 



