with ACI 548.4 and the following requirements. Mix and place
polymer-modified concrete only within the temperature limits recommended by
the polymer manufacturer. Prime the surface with a slurry of
polymer-modified mortar of the same composition as the polymer-modified
concrete except for coarse aggregate. Place polymer-modified concrete
before the prime coat dries. Place polymer-modified concrete within 15
minutes of addition of polymer. Moist cure overlay for not less than 24
hours nor more than 48 hours, then air dry.
3.10.3
Joints
Construct expansion and contraction joints in concrete overlay at the
locations shown. Maintain alignment of control joints within 1/4-inch, to
either side, of the required joint alignment. Construct expansion and
contraction joints at the locations shown and in accordance with Section
03150A EXPANSION JOINTS, CONTRACTION JOINTS, AND WATERSTOPS. Construct
expansion joints at existing joints using preformed expansion joint
material of the thickness shown and extending the full depth of the
overlay. Construct control joints by tooling the plastic concrete, then
sawcutting at the appropriate time. Saw control joints to a minimum [depth
of [ ] mm ([ ] inch(es))[ ] inch(es)][of 25 percent of the thickness of the
slab]. Maintain an ample supply of saw blades on the job before concrete
placement is started, and have at least one standby sawing unit in good
working order available at the jobsite at all times during the sawing
operations. Begin sawcutting as soon as it is possible to saw the concrete
without damaging adjacent concrete. Inspect the faces of joints during
sawcutting for undercutting or washing of the concrete due to early sawing.
Complete sawcutting within 16 hours of concrete placement. Continue
sawcutting regardless of weather conditions. Delay sawing if undercutting
is sufficiently deep to cause structural weakness or excessive roughness in
the joint or chipping, tearing, or spalling of the concrete occurs at the
surface. Discontinue sawing when a crack develops ahead of the saw cut.
Immediately after the joint is sawed, flush the saw cut and adjacent
concrete surface thoroughly with water until all residue from sawing is
removed from the joint. Control and dispose of waste water from sawcutting
and cleanup in accordance with Section 01355A ENVIRONMENTAL PROTECTION.
3.11
REFACING VERTICAL SURFACES
3.11.1
Cement-Based Concrete
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NOTE: Where there is concern about placement of
high lifts of refacing concrete, use the optional
text concerning lift height and placement time. The
permissible height of individual lifts and time
limit between placing lifts should be determined by
the form design to prevent overloading of the forms
and to maintain required construction tolerances.
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Install anchors and reinforcement as shown on the drawings. Place,
consolidate, finish and cure concrete in accordance with the applicable
requirements of Section [03300A CAST-IN-PLACE STRUCTURAL CONCRETE][03301A
CAST-IN-PLACE STRUCTURAL CONCRETE FOR CIVIL WORKS][Section 03307 CONCRETE
FOR MINOR STRUCTURES][Section 03371 SHOTCRETE]. Do not place concrete
when, in the opinion of the Contracting Officer, weather conditions prevent
proper placement, consolidation, and curing. [In order to prevent
overloading of forms, place concrete systematically in lifts not to exceed
SECTION 03931
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