15 March 2001
for curing the repair area. Curing should be started as soon as the concrete has set sufficiently.
Good curing is crucial to achieving a good repair.
4.15. Joint Sealing. Any longitudinal or transverse joints must be sealed. This reduces the
entry of water, which may cause pumping and faulting, and reduces the incidence and severity of
spalling. The transverse and longitudinal joint sealant reservoirs at the repair area may be
formed or sawed, while the concrete is green to control cracking. If the concrete cracks before
initial sawing, the resulting crack should be prepared and sealed. The initial cuts or dummy joints
must be prepared to function as a joint. This preparation begins after the curing period of the
concrete has ended. The preparation of joints in newly constructed PCC pavements are the
same for both field-molded and preformed materials.
4.15.1. After the initial sawing to control cracking of the concrete, the saw cuts should be
inspected for spalling. Spalls that extend more than 1/4 inch (6 millimeters) horizontally from the
sidewall of the initial cut should be repaired, since normally they would not be removed during the
widening operation. Void areas caused by honeycombing of the concrete must be patched to
provide a solid joint sidewall for the sealant to bond.
4.15.2. After the required curing period, the initial saw cut must be widened to the joint width and
depth specified in the project specifications using a self-propelled concrete saw. The depth of the
cut should be uniform, and the width should not vary along the length of the joint.
4.15.3. Following the sawing operation, the joint should be sandblasted to remove laitance,
curing compound, sawing dust, and other foreign debris from the joint sidewalls and from the
pavement surface adjacent to the joint to a width of approximately 1 to 2 inches (25 to 50 milli-
meters). A multiple pass technique has proven very successful in removing foreign debris. When
using the multiple pass technique, the nozzle is directed at one of the joint faces, and that face is
sandblasted the entire length of the slab. After one face has been completed, the nozzle is