per square m (25 pounds per 100 square feet) 25 pounds per 100 square feet.
Blend approximately two-thirds of the aggregate with portland cement as
recommended by the manufacturer and apply to the surface evenly and without
segregation. After blended material has been embedded by floating, apply
the remainder of the blended material to the surface at right angles to the
previous application. Apply blended material heavier in any areas not
sufficiently covered by the first application. Perform a second floating
immediately following the first. After the selected material has been
embedded by the two floatings, complete the operation with a [broomed]
[floated] [troweled] finish.
]3.8.1.6
Broomed
Use on surfaces of exterior walks, platforms, patios, and ramps, unless
otherwise indicated. 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.
3.8.1.7
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) 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) 1/8 inch.
3.8.1.8
Concrete Toppings Placement
The following requirements apply to the placement of toppings of concrete
on base slabs that are either freshly placed and still plastic, or on
hardened base slabs.
a.
Placing on a Fresh Base: Screed and bull float the base slab. As
soon as the water sheen has disappeared, lightly rake the surface
of the base slab with a stiff bristle broom to produce a bonding
surface for the topping. Immediately spread the topping mixture
evenly over the roughened base before final set takes place. Give
the topping the finish [indicated on the drawings] [specified
herein].
b.
Bonding to a Hardened Base: When the topping is to be bonded to a
floated or troweled hardened base, roughen the base by scarifying,
grit-blasting, scabbling, planing, flame cleaning, or acid-etching
to lightly expose aggregate and provide a bonding surface. Remove
dirt, laitance, and loose aggregate by means of a stiff wire
broom. Keep the clean base wet for a period of 12 hours preceding
the application of the topping. Remove excess water and apply a
1:1:1/2 cement-sand-water grout, and brush into the surface of the
base slab. Do not allow the cement grout to dry, and spread it
only short distances ahead of the topping placement. Do not allow
the temperature differential between the completed base and the
SECTION 03300N
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