9.1 Break and Seat

This process may be used to reduce the size of jointed reinforced concrete pavement (JRCP) to pieces on the order of about 1 to 2 ft.
2
 by repeatedly dropping a large weight. The objective is to retain some slab action, but reinforcing steel
must
 be ruptured or the bond broken. Typically, a drop hammer or “guillotine” type device is used as shown in Figure 7-4 and Figure 7-5. Broken PCC is then seated into the foundation using several passes of a 35 to 50 ton pneumatic roller.
Drop hammer breaking slab for break andseat operations.© Copyright 2006 University of Washington (click in image to see full-size image)
Figure 7-4. Drop hammer breaking slab for break and seat operations. © Copyright 2006 University of Washington
Drop hammer “breaking” slab for “breakand seat.”© Copyright 2006 University of Washington (click in image to see full-size image)
Figure 7-5. Drop hammer “breaking” slab for “break and seat.” © Copyright 2006 University of Washington