HomeMy WebLinkAboutBID - 6006 STEWART CASE PARK IMPROVEMENTS (64)City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 1 of 10
DIVISION 2
SECTION 02750 – PORTLAND CEMENT CONCRETE PAVING
PART 1 - GENERAL
1.01 Scope
A. Furnish all labor, materials, supplies, equipment, transportation, and perform all operations in
connection with and reasonably incidental to complete installation of concrete paving as shown on
the drawings and as specified herein. Items of work specifically included are:
B. Subgrade preparation for plazas, walks, ramps, playground curbs and headers.
C. Form work.
D. Reinforcement.
E. Surface finish.
F. Construction, expansion and control joints.
G. Curing.
H. Concrete plazas, sidewalks, ramps, playground curbs and headers.
I. Interior slabs-on-grade in restroom, etc.
1.02 Work Not Included
A. Items of work specifically excluded or covered under other sections:
B. Excavation and backfill.
C. Earthwork and grading.
D. Cast-in-place structural concrete or precast concrete, such as foundations, drainage appurtenances,
and pad and building.
E. Joint sealers.
1.03 Related Work
A. Division 2 – Site Work:
1. Section 02050 – Demolition.
2. Section 02200 – Earthwork/Grading.
3. Section 02220 – Trenching, Backfilling, and Compaction.
B. Division 3 – Concrete
1. Section 03100 – Concrete Formwork
2. Section 03200 – Concrete Reinforcing
3. Section 03300 – Cast-in-Place Concrete
C. Division 7 – Thermal and Moisture Protection:
1. Section 07900 – Joint Sealers.
1.04 References
A. ACI 301 – Specifications for Structural Concrete for Buildings.
B. ASTM C33 – Concrete Aggregate.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 2 of 10
C. ASTM C150 – Portland Cement.
D. ASTM C260 – Air Entraining Admixtures for Concrete.
E. ASTM C309 – Liquid Membrane – Forming Compounds for Curing Concrete.
F. ACI 304 – Recommended Practice for Measuring, Mixing, Transporting, and Placing Concrete.
G. ACI 305R – Hot Weather Concreting.
H. ACI 306R – Cold Weather Concreting.
I. ACI 308 – Standard Practice for Curing Concrete.
J. ACI 309 – Recommended Practice for Consolidation of Concrete.
K. ACI 318-89 – Building Code Requirements for Reinforced Concrete.
1.05 Regulatory Requirements
A. Conform to applicable code of governing authority for paving work within public right-of-way.
1.06 Tests
A. Submit proposed mix design to testing laboratory for review prior to commencement of work. For
standard premix concrete mixes, the supplier’s quality control records may be substituted for job
mix testing.
B. Refer to Division 1, Section 01450 Quality Control and Testing.
C. Coordinate and schedule sampling testing during concrete placement with City Representative.
1.07 Submittals
A. Submit product data under provisions of Section 01600 – Materials and Equipment.
B. Submit data on admixtures and curing compounds.
C. Submit a ten pound sample of aggregate for exposed aggregate finish.
D. Submit manufacturer’s data on leave-in-place construction joint form.
E. Submit sample chips of specified colors indicating pigment number and required dosage rate.
Submittals are for general verification of color and may vary somewhat from concrete finished in
field according to Specifications.
F. Submit samples of colored sealers.
1.08 Test Panels
A. Provide a 3’ x 3’ test panel for finish and tooling of joints for Owner approval. Provide one panel
for each pavement type specified. In casting the panels, use personnel and methods to be
employed on the work.
B. If sample disapproved, cast additional samples until approval is obtained. Maintain test panel on
site until finished work is accepted. Test panel will represent minimum workmanship standard.
C. Work completed prior to test panel approval shall be subject to removal and replacement at
Owner’s request.
PART 2 MATERIALS
2.01 Concrete Materials
A. General: Provide materials of same brand and source throughout the project unless otherwise
noted.
B. Portland Cement: ASTM C150, Type I or Type I/II, gray color.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 3 of 10
C. Aggregates: ASTM C33, normal weight. In addition, the combined aggregate shall comply with
the following gradation, shown in percent passing.
Sieve Size ¾-Inch Nominal Maximum Size
¾ Inch 90 – 100
3/8 Inch 60 – 80
No. 4 40 – 60
No. 8 30 – 45
No. 16 20 – 35
No. 30 13 – 23
No. 50 5 – 15
No. 100 0 – 5
D. Fly Ash and Water: Upon approval based on a satisfactory trial mix, the CONTRACTOR shall
have the option of substituting approved fly ash for Portland cement, up to a maximum of 20
percent by weight. The total weight of cement and fly ash shall not be less than the specified mix
design.
1. Fly ash for concrete shall conform to the requirements of ASTM C 618, Class C or Class F.
All chemical requirements of ASTM C 618 Table 1-A shall apply with the exception of
footnote A. Class C fly ash will not be permitted where sulfate resistant cement is required.
The CONTRACTOR shall submit certified laboratory test results for the fly ash. Test results
that do not meet the physical and chemical requirements may result in the suspension of the
use of fly ash until the corrections necessary have been taken to insure that the material meets
the specifications.
2. Water used in mixing or curing shall be clean and free of oil, salt, acid, alkali, sugar,
vegetable, or other substance injurious to the finished product. Water will be tested in
accordance with, and shall meet the suggested requirements of AASHTO T 26. Water known
to be of potable quality may be used without test. Where the source of water is relatively
shallow, the intake shall be so enclosed as to exclude silt, mud, grass, or other foreign
materials.
E. Coarse Aggregate for Exposed Aggregate Finish: 5/8-inch maximum size; rounded shape, ratio of
maximum to minimum dimensions not to exceed 2.5:1; color to be tan to brown, no more than 2%
white or black combined, no pink, no red, no green.
F. Water: Clean and not detrimental to concrete.
2.02 Pigments for Integrally Colored Concrete
A. Manufacturer:
1. Davis Colors manufactured by Davis Colors: phone (213) 269-7311.
2. Substitutions: Comply with Section 01600 for substitution request procedures.
B. Materials: Pigments shall contain pure, concentrated mineral pigments especially processed for
mixing into concrete and complying with ASTM C979.
C. Packaging: If pigments are to be added to mix at Site, furnish pigments in pre-measured Mix-
Ready disintegrating bags to minimize job site waste.
D. Colors: Concrete mix shall contain the dosage rate of pigments indicated in this specification.
Dosage rate shall be based on weight of Portland cement, fly ash, silica fume, lime and other
cementitious materials but not aggregate or sand. Refer to the site plans for locations of the
various colors of concrete.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 4 of 10
2.03 Form Materials
A. Slab Edges: Two by lumber permitted for surfaces not exposed to view in the final work. Use
concrete-form grade hardboard, “plyform” grade plywood, or metal for forming surfaces exposed
to view. Forms shall be straight and sufficiently stiff and well braced to meet line tolerances
specified in Part 3.
B. Keyed Joint Form: Wooden key or leave-in-place metal construction joint form.
C. Form Coatings: Commercial form-coating compounds that will not bond with, stain, or adversely
affect concrete surfaces, and will not impair subsequent treatments of concrete surfaces.
2.04 Reinforcement
A. Reinforcing Steel: ASTM A615; 60 ksi yield grade; deformed billet-steel bars, uncoated finish.
B. Fibermesh: Bundled, fibrillated, virgin polypropylene fibers manufactured for use in premix
concrete and having the following characteristics:
1. Special Gravity: 0.91.
2. Tensile Strength: 70 to 100 ksi.
3. Fiber Lengths: ½ inch, ¾ inch.
4. Accepted Materials: “Fibermesh” by Fibermesh Company of Chattanooga, TN; or “Forta
CR” by Forta Corporation of Groove City, PA.
C. Dowels: ASTM A615; 40 or 60 ksi yield grade, plain steel, uncoated finish; matched sleeve and
cap one end. Provide dowel basket to hold dowels in parallel alignment.
2.05 Admixtures
A. General: Unless specified in the mix or directed in Part 3, no admixtures shall be used without
approval of the Owner’s Representative. Do not use admixtures that would result in mixing water
with a concentration of more than 150 ppm of chloride ion.
B. Air Entraining: ASTM C260.
C. Water Reducing: ASTM C494, Type A.
D. Accelerator: Nonchloride, ASTM C494, Type C or E.
E. Retarder: ASTM C494, Type B or D.
F. Color Agent: Davis Colors of Los Angeles, California.
2.06 Related Materials
A. Expansion Joint Filler: ASTM D1752, closed cell polyethylene, ½ inch thickness.
B. Joint Sealant: See Section 07900.
C. Surface Retardant: Surface retarding agent intended for exposed aggregate. Retardx-SR0” by
Prokrete of Denver, Colorado, or approved equal.
D. Curing Compound for Standard Non-Colored Walks, Curbs, Gutters, Etc: White pigmented, wax-
resin based compound, ASTM C309, Type I, Class A. Recommended by manufacturer for use on
exterior sidewalks and driveways.
E. Curing Compound for Concrete with Coloring Agent: Davis Seal Color to match colored
concrete.
F. Curing Compound and Sealer for Exposed Aggregate Concrete: Acryseal by Prokete Industries
of Denver, Colorado.
G. Curing Compound for Interior Slabs: Protex Promulsion 100 or equal.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 5 of 10
H. Interior Floor Sealer: Protex Triple Seal or equal.
2.07 Concrete Mix
A. Mix concrete in accordance with ASTM C94.
1. Provide non-colored concrete for exterior slabs on grade, sidewalks, curb and gutter, walls,
aprons and ramps (except panel inserts) with the following characteristics:
Unit Measurement
a. 28-Day Field Compressive 4,000 psi
Strength
b. Cement/Fly Ash 615 lbs./cu. yd. Min.
c. Max. Water/Cement Ratio 0.44
d. Air Content % Range 5-8
e. Maximum Slump 4”
f. Fine Aggregate 50%
(max. % of total Aggregate)
2. Provide colored concrete for plazas, ramps and other flatwork with the following
characteristics:
Unit Measurement
a. 28-Day Field Compressive 4,000 psi
Strength
b. Cement/Fly Ash 615 lbs./cu. yd. Min.
c. Max. Water/Cement Ratio 0.44
d. Air Content % Range 5-8
e. Maximum Slump 4”
f. Fine Aggregate 50%
(max. % of total Aggregate)
g. Coloring Agent Per manufacturer’s recommendations
(refer to Definition of Bid Items and/or Drawings for
designated colors)
B. Use accelerating admixtures in cold weather as directed in Part 3.
C. Use set-retarding admixture during hot weather as directed in Part 3.
D. Water reducing agent is permitted.
2.08 Selection of Proportions
A. Mix Design: Cost of concrete mix design is responsibility of Contractor.
B. Selection of Proportions: Use method of ACI 301 3.9. Proportioning base on method of ACI 301
3.10 not allowed.
1. Field test records used for documentation of the average strength produced by a propos mix in
accordance with ACI 301 3.9.3.2 shall, in addition to the requirements listed, comply with the
following:
a. The test record shall represent production concrete from a single design mix produced
during the past year.
b. The test record shall represent concrete proportioned to produce the maximum slur
allowed by these specifications, and for air-entrained concrete, within a +0.5% of t
maximum air content allowed.
2. Mixes proportioned on the basis of trial mixtures shall meet the provisions of ACI 301
3.9.3.3.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 6 of 10
PART 3 EXECUTION
3.01 Subgrade Preparation
A. Shape and compact subgrade to match appropriate detail. Compact to 95% density as measured
by ASTM D698. Coordinate with Section 02200 – Earthwork, Article 3.05, Compaction.
B. Where subgrade cannot be compacted, remove subgrade. Replace with bed course. Compact to
95% density as measured by ASTM D698.
C. Moisten subgrade to minimize absorption of water from fresh concrete. Subgrade shall not be
muddy, soft, frozen, or covered with standing water when concrete is placed.
3.02 Form Work
A. General: Design, construct, and brace forms in accordance with ACI 301 and ACI 347. In
addition to those requirements, forms shall be placed and braced so the finished edges and joints
meet the tolerances listed later in this section.
B. Preparation of Form Surfaces:
1. Clean reused forms of concrete matrix residue; repair and patch as required to return forms to
acceptable surface condition.
2. Coat contact surfaces of forms with specified form-coating compound before reinforcement is
placed. Apply form-coating compound according to manufacturer’s instructions. Do not
allow excess form-coating material to accumulate in forms or to come in contact with
concrete surfaces against which fresh concrete will be placed.
C. Slipforming: Slipforming of vertical curb and gutter sidewalks is permitted.
D. For Surfaces Exposed To View: Form faces shall be free from raised grain, tears, worn edges,
patches, dents, or other defects which would impair texture of the concrete surfaces. Minimize
number of seams in form material, and arrange seams in an orderly manner.
3.03 Reinforcement and Embedments
A. General:
1. Fabricate, position, and secure reinforcement and embedded items according to ACI 301 and
ACI 315. Coordinate with other sections for locations, instructions, or equipment for
embedded items.
2. Shop drawings are not required.
3. Welding reinforcement is not permitted.
4. In the event of discrepancy, immediately notify the Owner’s Representative. Do not proceed
with installation in areas of discrepancy until all such discrepancies have been fully resolved.
B. Field-Bending of Reinforcement: Reinforcement partially embedded in concrete shall not be
field-bent, except as noted on the drawings or specifically permitted by the Owner’s
Representative.
C. Inspection of Reinforcement: Completed installation of concrete reinforcement must be reviewed
by the Owner’s Representative before depositing concrete.
D. Unless otherwise indicated, place reinforcement where required at top of slabs on grade. Provide
½-inch minimum cover over reinforcement.
E. Dowels: Grease sleeves, insert dowels and through form, secure dowel basket against movement.
F. Notches for Sleeving: Notch both vertical sides of walk or slab where sleeving occurs.
G. Welded wire fabric shall be overlapped one full mesh and tied.
H. Fibrous Reinforcement:
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 7 of 10
1. Add fibrous concrete reinforcement to concrete materials at the time concrete is batched in
amounts in accordance with approved submittals for each type of concrete required.
2. Mix batched concrete in accordance with manufacturer’s recommendations for uniform and
complete dispersion.
3.04 Joints
A. General: Place joints in accordance with ACI 301. Conform to the tolerances listed later in Part
3.
B. Isolation/Expansion Joints: Isolation joint and expansion joint are synonymous for concrete
paving.
1. Place isolation joints where work abuts existing walls, curbs and structures, and where shown
on the drawings.
2. Interrupt reinforcement at isolation joint. Install dowels only where indicated on drawings.
3. Joint filler shall extend full depth of the slab. Hold back filler from top of slab as required for
sealant. Attach joint filler to first placement.
4. Seal all expansion joints and joints between concrete and asphalt per Section 07900.
C. Keyed/Construction Joints: Keyed joint and construction joint are synonymous for concrete
paving.
1. Reinforcement, if required, shall continue through the joint.
2. Install where indicated on drawings, or where required by concrete delivery or finishing rate.
3. Key first placement. Key shall be 1½ inches wide and ¾ inches deep.
4. After first placement has hardened, clean and roughen face. Install control joint form at top
of slab.
5. Subject to Owner’s Representative approval; manufactured leave-in-place cold joint form
may be used.
D. Control/Score Joint: Control joint and score joint are synonymous for concrete paving.
1. Control joints shall penetrate 1/3 of slab thickness.
2. Sawn Joints: Control joints on play area curb shall be sawn. Kerf shall be 3/16-inch wide.
Start cutting as soon as concrete is able to be sawn without dislodging aggregate. Complete
cutting before shrinkage cracks occur. Joints perpendicular to walls may be less than required
depth within 6 inches of the wall, and may stop 2 inches from the wall. Wash slurry from
concrete to avoid staining of slab.
3. Tooled Joints: Control joints may be cut into the plastic concrete during finishing operations.
Tooled joints shall have ¼ radius, and shall not incorporate a troweled edge unless
specifically noted on the drawings.
4. Formed control joints are permitted only in conjunction with keyed joints.
5. Unless otherwise indicated, provide control joints at the following intervals:
Use Type Maximum Spacing
Uncolored Exterior & Tooled broom Symmetrically placed:
Interior Slabs, Sidewalks over joint 10’ maximum or 1 ½
times width of walk,
whichever is smaller
Curb and Gutter Tooled joints 10’ maximum
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 8 of 10
Pans Tooled joints 15’ maximum
Play Area Curb & Header Tooled joints 10’ maximum
Concrete Tooled joints 10’ maximum
3.05 Concrete
A. Preplacement Inspection: Form work installation, reinforcing steel placement, and installation of
all items to be embedded or cast in, to be verified by the Owner’s Representative prior to
placement.
B. General: Comply with ACI 301, ACI 304, and as herein specified.
C. Added Water: Concrete mix has been designed to a specific water cement ratio in order to
enhance durability of the final product. Do not add water at the job site or concrete will not be
accepted.
D. Cold Weather Placement: When depositing concrete after the first frost or when the mean daily
temperatures area below 40 degrees, follow recommendations of ACI 306 as modified herein.
Use specified accelerator. Maintain concrete temperature at a minimum of 55 degrees for not less
than 72 hours after depositing. Do not place concrete without approval of the Owner’s
Representative on days when temperature at 9:00 a.m. is below 30 degrees. Job-cured cylinders
for verification of strength and/or the adequacy of the Contractor’s protective methods will be
required.
E. Hot Weather Placement: When depositing concrete in hot weather, follow recommendations of
ACI 305 as modified herein. When the air temperature is expected to exceed 90 degrees, the
Contractor shall obtain acceptance from the Civil Engineer or Owner’s Representative of the
procedures to be used in protecting, depositing, finishing, and curing the concrete. The
temperature of concrete at the time of placement shall not exceed 90 degrees. Protect to prevent
rapid drying. Start finishing and curing as soon as possible. Specified water reducing retarding
admixture may be used. The use of continuous wetting or fog sprays may be required by the
Owner’s Representative for 24 hours after depositing.
F. Placing: Deposit and consolidate concrete slabs in a continuous operation, within the limits of
construction joints, until the placing of a panel or section is completed. Deposit concrete as nearly
as practicable in its final location to avoid segregation.
G. Consolidation: Consolidate concrete with internal vibrators with a minimum frequency of 7,000
rpm. Maintain one standby vibrator for every three vibrators used. Consolidate according to ACI
309. Do not transport concrete with vibrators. Work concrete into corners and around
embedments and reinforcement.
H. Surface Leveling: Strike off and level surface with screed of sufficient length to span the slab.
On slabs greater than 15 feet wide, use intermediate screed strips.
I. Integral colored concrete: Add color by weight directly into the mixer along with the aggregate,
cement and water while the mixer is operating at mixing speed. Continue mixing for 5-10 minutes
or from 50 – 100 revolutions.
3.06 Finishes
A. Float Finish: After surface stiffens enough to support the operation, float with hand floats or
powered disc floater. Use magnesium float; do not use wood float on air entrained concrete.
Check surface planeness with a 10-foot straight edge, applied at not less than two different angles.
Cut down high spots and fill low spots to produce a surface with Class B tolerance. Refloat the
slab to a uniform sandy texture.
B. Broom Finish: Concrete flatwork shall receive a heavy broom finish applied at a right angle to
the direction of travel. The plaza area shall have smooth troweled joints, 1½ inches from the
centerline of the joint, to result in a total trowel width of 3 inches. All other flatwork shall have
broom finish over joints.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 9 of 10
C. Exposed Aggregate Finish: Immediately after floating, apply surface retardant. Apply retardant
uniformly. Cover with polyethylene sheet to retain moisture. When mortar is hard enough to
retain aggregate but soft enough to be removed by brushing, wash the surface with water and
remove mortar from surface aggregate by brushing. Do not dislodge aggregate.
D. Coordinate rate of concrete placement with pace of washing crew.
E. Formed Finishes:
1. Surfaces Not Exposed to View: Patch tie holes and defects. Chip off fins greater than ¼ inch
in height.
2. Surfaces Exposed to View: Patch tie holes and defects. Completely remove fins.
F. Schedule of Finishes:
1. Curbs, gutters, ramps within ROW – per City Specifications.
2. Sidewalk – heavy broom finish.
3. Plaza paving – as shown on plans.
4. Playground curbs and header – exposed aggregate finish.
5. Interior slabs at restroom – medium broom finish.
G. Notch both vertical sides of concrete flatwork to indicate location of irrigation sleeves.
3.07 Curing/Sealing
A. Apply curing compound within 30 minutes of completing finish. Follow manufacturer’s
recommendations for applying compound. Reapply in areas exposed to rain within 3 hours of
initial application. Maintain continuity of coating and repair damage during 7-day curing period.
Follow manufacturer’s instructions for sealing interior slabs.
B. Integral colored concrete is to be cured with the matching Davis Color Seal. Follow
manufacturer’s recommendations for application.
3.08 Tolerances
A. Surface Planeness: Unless otherwise specified, produce slabs with a Class B tolerance.
1. Finishes with Class B tolerances shall be true planes within ¼ inch in 10 feet, as determined
by a 10-foot straight edge placed anywhere on the slab in any direction.
2. Slope interior slabs to drains as indicated.
B. Formed Surfaces, Joints, and Embedments: Unless otherwise specified, the finished work shall
meet the following tolerances:
1. Variations of formed, or cut or tooled linear element:
a. In 20 feet: ½ inch.
b. For entire length: 1 inch.
3.09 Field Quality Control
A. Field inspection and testing will be performed under provisions of Paragraph 1.06, Tests, and as
specified below.
B. Concrete Tests:
1. Shall be provided by the Contractor and shall be accordance with requirements of ACI 301,
Chapter 16 – Testing, except as noted or modified in this section.
a. Strength test.
i. Mold and cure four cylinders from each sample.
City of Fort Collins Section 02750 – Portland Cement Concrete Paving
Park Planning & Development Division Page 10 of 10
ii. Test one at 7 days and one at 14 days for information and one at 28 days for acceptance. Keep the
remaining one as a spare to be tested as directed by the Owner.
b. Minimum samples.
i. Collect the following minimum samples for each 28-day strength concrete used in
the work for each day’s placing:
Quantity Number of Samples
50 cubic yards or less one
50 to 100 cubic yards two
100 cubic yards or more two plus one sample for each
additional 100 cubic yards
c. Sample marking.
ii. Mark or tag each sample of compression test cylinders with date and time of day
cylinders were made.
iii. Identify location in work where concrete represented by cylinders was placed.
iv. Identify delivery truck or batch number, air content, and slump.
d. Slump test.
Conduct test for each strength test sample and whenever consistency of concrete appears
to vary.
e. Air content.
Conduct test from one of first three batches mixed each day and for each strength test
sample.
C. Acceptance of Concrete:
1. If the average of three consecutive 7-day tests falls below the specified 7-day strength, the
Owner shall have the right to require conditions of temperature and moisture necessary to
secure the required strength and may require core tests in accordance with ASTM C-42.
2. Strength level of concrete will be considered satisfactory so long as average of all sets of
three consecutive strength test results equals or exceeds specified 28-day strength and no
individual strength test result falls below specified strength by more than 500 psi.
D. Failure of Test Cylinder Results:
1. Upon failure of the 28-day test cylinder results, Owner may require Contractor, at his
expense, to obtain and test at least three cored samples from area in question.
2. Concrete will be considered adequate if average of three core tests is at least 85 percent of,
and if no single core is less than 75 percent of the specified 28-day strength.
3. Upon failure of core test results, Owner may require Contractor, at his expense, to perform
load tests as specified in ACI 318, Chapter 2.
4. In the event an area is found to be structurally unsound, the Owner may order removal and
replacement of concrete as required. The costs of the core tests, the load test and the
structural evaluation shall be borne by the Contractor.
5. Fill all core holes with a non-shrink grout as Master Builders Masterflo 713 or approved
equal.
E. Maintain records of placed concrete items. Record date, location of pour, quantity, air
temperature, and test samples taken.
END OF SECTION