reinforced concrete is located. Fiber reinforcing
is used to help: control cracking due to plastic
shrinkage; reduce permeability; and increase impact
capacity; shatter resistance, abrasion resistance,
and toughness. Fiber reinforcing will not: control
cracking due to structural stresses; significantly
increase strength; control curling or creeping;
justify reducing structural members; eliminate
control joints; or replace any moment or structural
steel reinforcement. Include flexural toughness
tests when synthetic reinforcement fibers are used
to increase toughness and when justified by size and
importance of job, but not when fibers are used only
to control plastic shrinkage cracking. Include
technical representative when warranted by size and
importance of job.
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In addition to the requirements specified above, fiber reinforced concrete
shall be provided in accordance with ASTM C 1116 Type III, synthetic fiber
reinforced concrete, and as follows. Synthetic reinforcing fibers shall be
100 percent virgin polypropylene fibrillated fibers containing no
reprocessed olefin materials. Fibers shall have a specific gravity of 0.9,
a minimum tensile strength of 480 MPa (70 ksi) 70 ksi, graded per
manufacturer, and specifically manufactured to an optimum gradation for use
as concrete secondary reinforcement. A minimum of 2.6 kg of fibers per
cubic meter (1.5 pounds of fibers per cubic yard)1.5 pounds of fibers per
cubic yard of concrete shall be used. Fibers shall be added at the batch
plant. [Toughness indices shall meet requirements for performance level
I.] [Provide the services of a qualified technical representative to
instruct the concrete supplier in proper batching and mixing of materials
to be provided.]
PART 3
EXECUTION
3.1
FORMS
ACI 301. Provide forms, shoring, and scaffolding for concrete placement.
Set forms mortar-tight and true to line and grade. Chamfer above grade
exposed joints, edges, and external corners of concrete 20 mm (0.75 inch)
0.75 inch unless otherwise indicated. Provide formwork with clean-out
openings to permit inspection and removal of debris. Forms submerged in
water shall be watertight.
3.1.1
Coating
Before concrete placement, coat the contact surfaces of forms with a
nonstaining mineral oil, nonstaining form coating compound, or two coats of
nitrocellulose lacquer. Do not use mineral oil on forms for surfaces to
which adhesive, paint, or other finish material is to be applied.
3.1.2
Removal of Forms and Supports
After placing concrete, forms shall remain in place for the time periods
specified in ACI 347R. Prevent concrete damage during form removal.
3.1.2.1
Special Requirements for Reduced Time Period
Forms may be removed earlier than specified if ASTM C 39 test results of
SECTION 03300N
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