TM 5-822-7/AFM 88-6, Chap. 8
molds furnished are satisfactory will be i n c l u d e d
be used primarily to smooth and check the surface.
in the contract specifications.
To avoid later costly corrections of hardened pave-
ment which fails to conform with specified surface
b. Specimens for strength tests. Test specimens
tolerances, the surface will be thoroughly checked
for determining conformance with specified strength
requirements will be moist-cured under field
during the mechanical floating, and necessary
laboratory conditions. The size and number of curing
corrections will be made.
tanks will depend on the number of specimens taken
c. Hand finishing and edging. Machine finishing is
and the "ages at which the tests are made. For airfield
required, and hand finishing is only permitted for
paving projects, flexural-strength tests will be
odd widths and shapes of slabs, areas adjacent to
conducted at the ages of 7, 14, and 90 days. For other
headers, and areas around outlets in the pavements.
pavements, designed on the basis of 28-day flexural
Hand-finished areas will have the same quality and
the same surface characteristics as those areas finished
strengths, the test ages will be 7, 14, and 28 days.
Where 90-day flexural strength tests are required,
by machine. Hand finishing along the edges of slip-
provision will be made for curing and testing of
formed lanes to correct edge slumping or to repair
specimens after the project is completed.
areas damaged by tearing or sloughing shall be held
c. Specimens for determining time of opening
to a minimum. The only manipulation permitted
pavement to construction traffic. Ordinarily, no
along the edges of slipformed lanes shall not disturb
field-cured specimens will be required. However, for
the edge or use the edging tools to correct deficiencies
in the edge.
cold-weather construction when field-strength data
may be necessary to permit the opening of the pave-
d. Surface texture. The final surface texture of the
ment or portions thereof to construction traffic prior
pavement will be provided by means of a burlap
to 14 days, test groups of at least three beams shall
drag, broom, artificial turf, wire comb, or grooving.
be taken, as required, from concrete placed in
Dragging the surface of the concrete in the direction
designated areas. The beams of each test group shall
of concrete placement with moist burlap leaves a fine
be made from a single batch of concrete and shall be
sandy surface that is adequate for low-speed traffic.
cured in accordance with ASTM C 31.
At least 2 feet of burlap must be in contact with the
concrete, and the burlap should be cleaned as
necessary. An improved skid-resistant surface can
18. Finishing.
a. Equipment and methods. Types of finishing
be produced with a broom consisting of multiple
rows of stiff bristles capable of producing serrations
equipment other than conventional equipment may
be used on a trial basis when capable of finishing
1/16 to1/8 of an inch deep. The brooms will have to be
cleaned frequently during texturing. Artificial turf
concrete of the quality and consistency required.
has been used successfully for texturing concrete.
Equipment that fails under trial to perform in a
This is applied in the same manner as the burlap with
satisfactory manner will be rejected and removed
from the work area.
at least 2 feet of the artificial turf in contact with the
concrete. One artificial turf that has provided a
b. Surface finishing and testing. Finishing opera-
satisfactory texture consisted of 7,200 polyethylene
tions are designed to obtain a dense, smooth surface
turf blades approximately 0.85 inch long per square
true to the required grade. Since the surface receives
foot. The wire comb provides the most skid-resistant
the greatest exposure to weathering and traffic,
texture of the finishing techniques described so far.
every precaution will be taken to obtain a high-quality
However, it is also the most difficult to use and
concrete at the surface. The finishing operations will
adjustments to the concrete proportions may have to
be kept to the minimum necessary to obtain the
be made to find a mixture that can be wire-combed
required surface finish. Excessive surface manipula-
without objectionable surface tearing. The wire
tion will not be permitted because it tends to bring a
comb should consist of flexible spring steel lines
surplus of mortar, water, and undesirable soft
spaced not less than 1/2 inch nor more than 1 inch
materials to the surface which contributes to scaling
apart. Closer spacing causes problems with raveling,
and surface deterioration. Finishing should leave the
surface at the proper grade. If the mechanical
and wider spacing results in objectionable road
noise. The serrations left by the steel lines should be
finishing operations are properly controlled, very little
hand finishing will be necessary. Short floats will be
about 1/8 to 1/4 inch deep and 1/16 to 1/8 inch wide. A single
pass of burlap or artificial turf can be made before
used only as necessary to correct local surface
the wire comb if desired. Because of problems with
uneveness. Straightedges of the required length will
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