15 March 2001
4.2.8. Railroad crossing distress.
Many rigid pavements are also subject to spalling and faulting at intermediate cracks. This
deterioration may be caused by repeated heavy traffic loads, failure of doweled joints to function
properly, and/or the intrusion of incompressible materials in the open cracks.
4.3. Selection of Repair Boundaries. First,
a detailed survey should
identify the required repair areas so that all significant underlying distresses are found. Quite
often, and particularly in freeze-thaw climates, the deterioration near joints and cracks is greater
at the bottom of the slab than is apparent from the top of the slab Figure 4.2.). In both plain
jointed and reinforced jointed concrete pavement, partial-slab replacement is acceptable where
the distresses are within one-half of the slab length. Full-width slab patching is required if the
original slab length is less than 20 feet (6 meters), or full-depth cracks are located within the
interior area of the slab. A minimum slab length is required to avoid rocking and pumping of the
repair. General experience indicates that 10 feet (3 meters) or one-half of the slab length, which
ever is less, is a minimum length when load transfer is provided.
The recommended minimum patch dimensions are:
4.3.1. Saw cut will be a minimum of 2 feet (600 millimeters) from joint (Figure 4.3.).
4.3.2. If patch is a utility cut, make cut 6 to 12 inches (150 to 300 millimeters) beyond limits of the
excavation and any sluffing of the trench (Figure 4.4.).
4.3.3. For continuously reinforced concrete, the disressed portion must be in the middle of the
patch area. Patch should be 6 feet (1.8 meters) long if steel is to be tied, and 4 feet (1.2 meters)
long, if welded.