mix design, one by one m, 75 mm 3 by 3 feet, 3 inches thick. Use the
approved concrete mix design(s). Provide sample panels on-site at
locations directed. Once approved, each set of panels shall be
representative of each of the finishes specified and shall be
representative of the workmanship and finish required. Do not remove or
destroy samples until directed by the Contracting Officer.
]3.6
FINISHES FOR HORIZONTAL CONCRETE SURFACES
3.6.1
Finish
ACI 301. Place, consolidate, and immediately strike off concrete to obtain
proper contour, grade, and elevation before bleedwater appears. Permit
concrete to attain a set sufficient for floating and supporting the weight
of the finisher and equipment. If bleedwater is present prior to floating
the surface, drag excess water off or remove by absorption with porous
materials. Do not use dry cement to absorb bleedwater.
3.6.1.1
Scratched
Use for surfaces intended to receive bonded applied cementitious
applications. After the concrete has been placed, consolidated, struck
off, and leveled, the surface shall be roughened with stiff brushes of
rakes before final set.
3.6.1.2
Floated
[Exterior slabs where not otherwise specified.] After the concrete has
been placed, consolidated, struck off, and leveled, do not work the
concrete further, until ready for floating. Whether floating with a wood,
magnesium, or composite hand float, with a bladed power trowel equipped
with float shoes, or with a powered disc, float shall begin when the
surface has stiffened sufficiently to permit the operation.
3.6.1.3
Concrete Containing Silica Fume
Finish using magnesium floats or darbies.
[Finish using techniques
demonstrated in the sample installation.]
3.6.1.4
Broomed
Perform a floated finish, then draw a broom or burlap belt across the
surface to produce a coarse scored texture. Permit surface to harden
sufficiently to retain the scoring or ridges. Broom transverse to traffic
or at right angles to the slope of the slab.
3.6.1.5
Pavement
Screed the concrete with a template advanced with a combined longitudinal
and crosswise motion. Maintain a slight surplus of concrete ahead of the
template. After screeding, float the concrete longitudinally. Use a
straightedge to check slope and flatness; correct and refloat as necessary.
Obtain final finish by [belting. Lay belt flat on the concrete surface
and advance with a sawing motion; continue until a uniform but gritty
nonslip surface is obtained.] [a burlap drag. Drag a strip of clean, wet
burlap from 900 to 3000 mm wide and 600 mm longer 3 to 10 feet wide and 2
feet longer than the pavement width across the slab . Produce a fine,
granular, sandy textured surface without disfiguring marks.] Round edges
and joints with an edger having a radius of 3 mm 1/8 inch.
SECTION 03311
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