15 March 2001
SPALL REPAIR PREPARATION
15.1. Description. As with most concrete repairs, an essential element of the spall repair
operation is the proper preparation of the spalled area. If the prepared spalls are dirty or contain
excess moisture, the repair material or bonding agent will not completely adhere to the surface.
The spall repair operation must be scheduled such that the prepared areas are filled as soon as
possible to prevent contamination of the surface. The importance of proper cleaning of the repair
area cannot be overemphasized. After completion of the sawing and removal of the concrete, the
recess must be cleaned by airblasting and waterblasting to remove concrete chips, laitance,
sawing debris, and other foreign material from the recess. The area must then be thoroughly
swept, using a vacuum broom if available, to prevent debris from reentering the spall repair area.
15.2. Detailed Schematics. Detailed schematics of spall repair for construction and keyed joints
are presented in Figures 3.1. to 3.4. Figure 3.1. provides details for determining the boundary
around the spall where the sawcuts should be located. Repair boundaries for corner spalls and
joint spalls at both construction and keyed joints are shown. Closeup details for each of the types
of spall repair located in various positions around a slab are given in Figures 3.2. to 3.4.
Figure 3.5. shows details for joint sealant repair, and Figure 3.6. gives details for repair of
To begin the saw and patch procedures, mark the boundaries
of the area
make the sawcuts easier and decide which repair material(s) are to be employed in the patching
effort. Remove the joint or crack sealant a few inches on either side of the spall. The sawcuts
must be at least 2 inches (50 millimeters) deep and 2 to 3 inches (50 to 80 millimeters) outside
the boundary of the spall (Figure 3.2. and Figure 14.1.). For joint and crack spalls in Army, Air