thickness shall be removed.
3.9.3
Removal and Replacement of Full Slabs
Where it is necessary to remove full slabs, removal shall be in accordance
with paragraph: Removal of Existing Pavement Slab. Removal and replacement
shall be full depth, by full width of the slab, and the limit of removal
shall be normal to the paving lane and extend to each original joint.
Where there are no dowels, tie bars, or keys on an edge, or where they have
been damaged, dowels of the size and spacing as specified for other joints
in similar pavement shall be installed by epoxy grouting them into holes
drilled into the existing concrete using procedures as specified in
paragraph: Placing Dowels and Tie Bars. Original damaged dowels or tie
bars shall be cut off flush with the joint face. Protruding portions of
dowels shall be painted and lightly oiled. All four edges of the new slab
shall thus contain dowels [or original keys or original tie bars].
Placement of concrete shall be as specified for original construction.
Prior to placement of new concrete, the underlying material shall be
recompacted and shaped as specified in the appropriate section of these
specifications, and the surfaces of all four joint faces shall be cleaned
of all loose material and contaminants and coated with a double application
of membrane forming curing compound as bond breaker. Care shall be taken
to prevent any curing compound from contacting dowels or tie bars. The
resulting joints around the new slab shall be prepared and sealed as
specified for original construction. In lieu of protecting existing tie
bars, tie bars may be cut off, and replaced by epoxying new tie bars into
drilled holes to match design plans.
3.9.4
Repairing Spalls Along Joints
Where directed, spalls along joints of new slabs, along edges of adjacent
existing concrete, and along parallel cracks shall be repaired by first
making a vertical saw cut at least 25 mm 1 inch outside the spalled area
and to a depth of at least 50 mm 2 inches. Saw cuts shall be straight
lines forming rectangular areas. The concrete between the saw cut and the
joint, or crack, shall be chipped out to remove all unsound concrete and
into at least 12 mm 1/2 inch of visually sound concrete. Spalls along
joints to be sealed with compression seals shall be sawn, chipped out, and
repaired to a depth to restore the full joint-face support. The cavity
thus formed shall be thoroughly cleaned with high pressure water jets
supplemented with oil-free compressed air to remove all loose material.
Immediately before filling the cavity, a prime coat shall be applied to the
dry cleaned surface of all sides and bottom of the cavity, except any joint
face. The prime coat shall be applied in a thin coating and scrubbed into
the surface with a stiff-bristle brush. Prime coat for portland cement
repairs shall be a neat cement grout and for epoxy resin repairs shall be
epoxy resin, Type III, Grade 1. The prepared cavity shall be filled with:
Portland cement concrete or latex modified mortar for larger cavities,
those more than 0.009 cubic meter 1/3 cu. ft. in size after removal
operations; Portland cement mortar for cavities between 0.00085 cubic meter
0.03 cu. ft. and 0.009 cubic meter 1/3 cu. ft.; and epoxy resin mortar or
epoxy resin or latex modified mortar for those cavities less than 0.00085
cubic meter 0.03 cu. ft.in size. Portland cement concretes and mortars
shall be very low slump mixtures, 12 mm 1/2 inch slump or less,
proportioned, mixed, placed, consolidated by tamping, and cured, all as
directed. Epoxy resin mortars shall be made with Type III, Grade 1, epoxy
resin, using proportions and mixing and placing procedures as recommended
by the manufacturer and approved by the Contracting Officer. Proprietary
patching materials may be used, subject to approval by the Contracting
SECTION 02753
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