SECTION 0310
CAST-IN-PLACE CONCRETE
PART 1.00 - GENERAL
1.01
SCOPE OF WORK:
A.
WORK INCLUDED: The Contractor shall furnish all necessary materials, labor,
equipment and services to perform all cast-in-place concrete work as indicated by
the drawings and specified herein including, but not necessarily limited to the
following:
1.
2.
3.
4.
5.
6.
7.
B.
RELATED WORK SPECIFIED ELSEWHERE:
1.
2.
3.
4.
5.
6.
1.02
Concrete footings and foundations.
Concrete walls and foundations.
Concrete slabs on grade.
Concrete steps and landings.
Vapor barrier under slabs on grade.
Formwork and forming accessories for concrete work.
Compressible expansion joint fillers in concrete work.
Fine Grading under Concrete Slabs on Grade - Section 0210.
Compaction of Subgrade under Concrete Slabs on Grade - Section 0210.
Exterior Concrete Slabs and Aprons - Section 0230.
Reinforcing Steel and Mesh - Section 0320.
Embedded Miscellaneous Steel Items - Section 0540.
Caulking of Joints in Concrete Work - Section 0790.
APPLICABLE CODES AND STANDARDS:
A.
CODES: All work specified under this Section shall comply with the following
codes:
1.
2.
B.
North Carolina State Building Codes.
"Building Code Requirements for Reinforced Concrete", ACI 318, Latest
Edition.
STANDARDS: All work specified under this Section shall comply with all
applicable requirements of the following standard specifications. In the event that
requirements of standard specifications conflict with requirements of the project
specifications, the project specifications shall govern.
1.
2.
"Specifications for Structural Concrete for Building" ACI 301, latest edition.
Standards of the American Society for Testing Materials (ASTM) as listed
below:
0310-1
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
C31
-
Standard Method of Making and Curing Concrete
Compressive and Flexural Strength Test Specimens
in the Field.
C33
-
Standard Specifications for Concrete Aggregates.
C39
-
Standard Method of Test for Compressive Strength
of Molded Concrete Cylinders.
C42
-
Standard Method of Obtaining and Testing Drilled
Cores and Sawed Beams of Concrete.
C94
-
Standard Specification for Ready-Mix Concrete.
C138
-
Standard Method of Test for Weight Per Cubic Foot,
Yield, and Air Content (Gravimetric) of Concrete.
C143
-
Standard Method of Test for Slump of Portland
Cement Concrete.
C150
-
Standard Specification for Portland Cement.
C171
-
Standard Specification for Sheet Materials for Curing
Concrete.
C172
-
Standard Method of Sampling Fresh Concrete.
C173
-
Standard Method of Test for Air Content of Freshly
Mixed Concrete by the Volumetric Method.
C192
-
Standard Method of Making and Curing Concrete
Test Specimens in the Laboratory.
C231
-
Standard Method of Test for Air Content of Freshly
Mixed Concrete by the Pressure Method.
C260
-
Standard Specification for Air-Entraining Admixtures
for Concrete.
C309
-
Standard
Specifications
for
Membrane-Forming
Compounds
for
Concrete.
C387
-
Standard Specifications for Packaged,
Combined Materials for Mortar and Concrete.
C494
-
Standard Specification for Chemical Admixtures for
Concrete.
0310-2
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
Liquid
Curing
Dry,
C567
-
Standard Method of Test for Unit Weight of
Structural Lightweight Concrete.
C881
-
Standard Specification for
Bonding System for Concrete.
Resin-Base
D1751 -
Standard Specifications for Preformed Expansion
Joint Fillers for Concrete Paving and Structural
Construction
(Non-extruding
and
Resilient
Bituminous Types.)
D1752 -
Standard Specification for Preformed Sponge
Rubber and Cork Expansion Joint Fillers for
Concrete Paving and Structural Construction.
E329
3.
Epoxy
-
Recommended Practice for Inspection and Testing
Agencies for Concrete and Steel as Used in
Construction.
Standards and recommended practices of the American Concrete Institute
(ACI) as listed below:
ACI 211.1
-
Recommended Practice for Selecting Proportions for
Normal, Heavyweight, and Mass Weight Concrete.
ACI 212.3R
-
Chemical Admixtures for Concrete.
ACI 214
-
Recommended Practice for Evaluation of Strength
Test Results of Concrete.
ACI 302.1R
-
Guide for Concrete Floor and Slab Construction.
ACI 304R
-
Guide for Measuring, Mixing, Transporting, and
Placing Concrete.
ACI 304.2R
-
Placing Concrete by Pumping Methods.
ACI 305R
-
Hot Weather Concreting.
ACI 306R
-
Cold Weather Concreting.
ACI 306.1
-
Standard Specification for Cold Weather Concreting.
ACI 308
-
Standard Practice for Curing Concrete.
ACI 309R
-
Guide for Consolidation of Concrete.
0310-3
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
C.
1.03
1.04
ACI 347R
-
Guide to Formwork for Concrete.
ACI 503.4
-
Standard Specifications for Repairing Concrete with
Epoxy Mortars.
MANUFACTURER'S INSTRUCTIONS: Unless otherwise specified herein, all
materials shall be used and installed in strict accordance with the manufacturer’s
written instructions.
SUBMITTALS:
A.
MIX DESIGNS: Mix designs prepared by an independent laboratory suitable to
the Engineer shall be submitted to the Engineer for each type or class of concrete
required for the project in accordance with Section 0130. Mix designs shall include
gradation analysis for aggregates. No concrete shall be placed until mix designs
are approved by the Engineer.
B.
TEST REPORTS: Test reports prepared by an independent laboratory suitable to
the Engineer shall be submitted to the Engineer in accordance with Section 0130.
C.
MILL TEST REPORTS: Mill test reports for shipments of cement shall be
furnished to the Engineer if requested.
D.
MANUFACTURER’S LITERATURE: Manufacturer’s literature shall be submitted in
accordance with Section 0130 for all manufactured products specified.
PRODUCT HANDLING:
A.
PROTECTION:
1.
2.
3.
4.
General: All necessary means shall be used to protect materials and work
specified under this section from damage before, during and after
installation.
Work of Other Trades: All necessary means shall be used to protect work
of other trades from damage resulting from work specified under this
Section.
Cold Weather Protection: Concrete work shall be adequately protected
from freezing. When the mean daily outdoor temperature is lower than 40
degrees F, all concrete work shall be protected in accordance with the
requirements and recommendations of ACI 306R "Cold Weather
Concreting" and ACI 306.1 "Standard Specification for Cold Weather
Concreting". When the temperature of the surrounding air is expected to
be below 40 degrees F during placing or within 24 hours thereafter, the
temperature of the plastic concrete, as placed, shall be no lower than 55
degrees F for sections less than 12 inches in any dimension nor 50
degrees F for any other sections.
Hot Weather Protection: Concrete shall be adequately protected from
premature setting by evaporation of water. When the outdoor temperature
0310-4
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
5.
6.
B.
STORAGE OF MATERIALS:
1.
2.
1.05
is 90 degrees F or above and at lower temperatures combined with drying
winds, all concrete work shall be protected in accordance with the
requirements and recommendations of ACI 305R "Hot Weather
Concreting". The temperature of the concrete as placed shall not be so
high as to cause difficulty from loss of slump, flash set, or cold joints and
should not exceed 90 degrees F. When the temperature of the concrete
exceeds 90 degrees F, precautionary measures approved by the Engineer
shall be put into effect. When the temperature of the steel is greater than
120 degrees F, steel forms and reinforcement shall be sprayed with water
just prior to placing the concrete.
Falling Weather: Concrete in unprotected areas shall not be placed during
rain, sleet, or snow. Rainwater shall not be allowed to increase the mixing
water nor to damage the surrounding finish.
Mechanical Injury: During the curing period, the concrete shall be
protected from damaging mechanical disturbances, such as load stresses,
heavy shock, and excessive vibration. All finished concrete surfaces shall
be protected from damage by construction equipment, materials, or
methods, by application of curing procedures, and by rain or running water.
All materials subject to damage from dampness or inclimate weather shall
be suitably stored in waterproof construction warehouses or the equivalent.
Materials for concrete shall be stored in accordance with Section 2.5 of ACI
301 latest edition, "Specifications for Structural Concrete for Buildings".
C.
REPLACEMENTS: In the event of damage to materials or work in place, all
necessary repairs and replacements shall be immediately made to the satisfaction
of the Engineer at no additional cost to the Owner.
D.
PACKAGING AND MARKING: All manufactured materials shall be delivered to
the jobsite in the manufacturers' standard containers, packages or bags bearing
the manufacturer's standard identification, labels, instructions, etc.
ENVIRONMENTAL CONDITIONS:
A.
COLD WEATHER: When the mean daily outdoor temperature is lower than 40
degrees F, all concrete work shall be performed in accordance with the
requirements and recommendations of ACI 306R, "Cold Weather Concreting" and
ACI 306.1 "Standard Specification for Cold Weather Concreting".
B.
HOT WEATHER: When the outdoor temperature is 90 degrees F or above and at
lower temperatures combined with drying winds, all concrete work shall be
performed in accordance with the requirements and recommendations of ACI
305R, "Hot Weather Concreting".
0310-5
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
1.06
COORDINATION:
A.
1.07
The work of this Section shall be coordinated with the work of other Sections to
insure that all required sleeves, inserts, embedded items, blockouts, and similar
items are properly in place prior to placing of concrete.
ACCEPTANCE AND TOLERANCES:
A.
GENERAL ACCEPTANCE: Concrete materials and operations will be tested and
inspected as the work progresses. Failure to detect any defective work or
materials shall not in any way prevent later rejection when such defect is
discovered nor shall it obligate the Engineer for final inspection.
B.
ACCEPTANCE OF CONCRETE STRENGTH: The strength level of the concrete
will be considered satisfactory so long as the averages of all sets of three
consecutive field strength test results equal or exceed the specified strength f'c,
and no individual strength test result falls below the specified strength f'c by more
than 500 psi. Concrete not meeting these criteria shall be core drilled, tested, and
evaluated in accordance with Chapter 17 of ACI 301 latest edition and Section 5.6
of ACI 318, latest edition. Results of such testing shall be forwarded to the
Engineer for consideration. Final acceptance of concrete shall be the sole
determination of the Engineer. All costs associated with testing of in place
concrete shall be solely borne by the Contractor.
C.
ACCEPTANCE OF THE COMPLETED CONCRETE WORK: Acceptance of the
completed concrete work will be based on the requirements and stipulations set
forth in Chapter 18 of ACI 301 latest edition.
D.
TOLERANCES:
1.
2.
Formed Surfaces: Dimensional tolerances for concrete surfaces shall be
as specified in paragraph 4.3 of ACI 301 latest edition, "Specifications for
Structural Concrete for Buildings".
Flatwork: Finishing tolerances for concrete flatwork shall be as follows:
a.
b.
Class A: Finished surface shall be a true plane within 3/16 inch in
ten (10) feet as determined by a ten (10) foot straightedge placed
anywhere on the slab in any direction. Elevations shall be within
plus or minus 1/4 inch of elevations indicated on drawings. All
interior exposed concrete slabs and shall have a Class A tolerance.
Class B: Finished surface shall be a true plane within 5/16 inch in
ten (10) feet as determined by a ten (10) foot straightedge placed
anywhere on the slab in any direction. Elevations shall be within
plus or minus 1/4 inch of elevations indicated on drawings. Exterior
concrete slabs and concrete walkways shall have a Class B
tolerance.
0310-6
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
1.08
FIELD REFERENCE MANUAL:
A.
At least one copy of the Field Reference Manual, American Concrete Institute
Publication SP-15 (latest edition) shall be kept on the project at all times. The
contents of this manual as referred to by these specifications are hereby made a
part of the specifications for this project to same extent as if fully bound herein.
PART 2.00 - PRODUCTS
2.01
MATERIALS:
A.
PORTLAND CEMENT shall be Type I, conforming to the requirements of ASTM
C150. All cement used in work shall be the same as that used in design mixes.
B.
AGGREGATES for concrete of normal weight shall conform to the requirements of
ASTM C33. Fine and coarse aggregates shall be regarded as separate
ingredients. Each size of coarse aggregate, as will as the combination of sizes
when two or more are used, shall conform to the appropriate grading requirements
of the applicable ASTM specifications.
C.
MIXING WATER for concrete shall be fresh, clean and drinkable. Mixing water
shall not contain a deleterious amount of chloride ion when combined with that
contributed by aggregates.
D.
AIR ENTRAINING ADMIXTURE shall meet the requirements of ASTM C260.
Air entraining admixtures shall be one of the following or approved equal:
1.
2.
3.
E.
WATER REDUCING ADMIXTURE shall meet the requirements of ASTM
C494, Type A. Water reducing admixture shall be one of the following or
approved equal:
1.
2.
3.
F.
MB AE90 by Master Builders, Inc., Cleveland, OH.
AEA 92 by Euclid Chemical Company, Cleveland, OH.
Darex II AEA by Grace Construction Products, Cambridge, MA.
Pozzolith 322-N by Master Builders, Inc., Cleveland, OH.
Eucon WR75 by Euclid Chemical Company, Cleveland, OH.
WRDA with Hycol by Grace Construction Products, Cambridge, MA.
LIQUID CURING COMPOUND for exposed interior floor slabs shall be one of
the following or approved equal:
1.
2.
3.
Masterkure 200W by Master Builders, Inc., Cleveland, OH.
Super Aqua-Cure VOX by Euclid Chemical Company, Cleveland, OH.
Conspec #1-30 by Conspec, Kansas City, KS.
0310-7
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
Liquid curing compound for exterior concrete and foundations shall be one of
the following or approved equal:
1.
2.
3.
Masterkure-N-Seal VOC by ChemRex, Inc., Shakopee, MN.
Eucocure VOX by Euclid Chemical Company, Cleveland, OH.
Cure and Seal VOC by Conspec, Kansas City, KS.
Liquid curing compounds shall meet the requirements of ASTM C309.
G.
VAPOR BARRIER beneath exposed concrete slabs on grade shall be six mil
polyethylene unless otherwise specified.
H.
EXPANSION JOINT FILLER MATERIALS shall be non-extruding resilient,
bituminous type conforming to the requirements of ASTM D1751 unless otherwise
specified. Expansion joint filler materials at radius joints shall be preformed
sponge rubber type joint filler conforming to ASTM D1752, Type I. Joints that
receive caulking or sealant shall be fitted with Snap-Cap as manufactured by W.R.
Meadows, Inc., Elgin, Illinois or approved equal.
I.
NON-SHRINK GROUT (when and where required by the drawings) shall be
one of the following premixed non-metallic grouts or approved equal:
1.
2.
3.
Set Grout by Master Builders, Inc., Cleveland, OH.
Euco N-S by Euclid Chemical Co., Cleveland, OH.
F-77 Construction Grout by WR Bonsal Co., Charlotte, NC.
Grout shall have a minimum flowable compressive strength of 7,000 psi at 28
days and meet the requirements of Corps of Engineers specification CRD-C621 and ASTM C1107.
J.
FORM MATERIALS shall be of good quality, straight and true; and capable of
producing the quality of cast-in-place concrete work as specified elsewhere in this
Section of the specifications. Patented concrete panel forms shall not be used for
exposed concrete work unless a smooth form liner is used on the exposed
surface.
K.
CHAMFER STRIPS shall be 3/4 inch by 3/4 inch made from molded plastic or
wood. Chamfer strips shall be provided and kept in such a condition as to yield
sharp, true, uniform chamfered edges.
L.
FORM TIES AND ACCESSORIES shall be commercially manufactured types.
The portion of ties or accessories permanently cast into concrete shall not
extend closer than 3/4 inch to finished surfaces of concrete. Ties and
accessories shall be as manufactured by one of the following or approved
equal:
0310-8
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
1.
2.
Dayton/Richmond Concrete Accessories, Miamisburg, OH.
Meadow Burke, Tampa, FL.
M.
FORM COATING MATERIAL shall be nonstaining type that prevent bond with
concrete and prevents absorption of water by forms. Form coating material shall
be Rich-Cote as manufactured by Richmond Screw Anchor Co., Brooklyn, N.Y. or
approved equal.
N.
EPOXY PATCHING COMPOUND shall be two component aggregate filled
epoxy resin concrete patching compound.
Epoxy patching compound shall
be one of the following or approved equal:
1.
2.
3.
O.
Euro 700 by Euclid Chemical Company, Cleveland, OH.
Masterfill 300I by master Builders Inc., Cleveland, OH.
Spec Joint CJ by Conspec, Kansas City, KS.
NON-SLIP ABRASIVE AGGREGATE shall be a 95% aluminum oxide abrasive
aggregate. Abrasive aggregate shall be one of the following or approved
equal:
1.
2.
3.
Sonneborn Sonocrete Frictex NS by ChemRex, Inc., Shakopee, MN.
Emery Non-Slip (95% AO) by Dayton/Superior, Kansas City, KS.
Aluminax by Specon, Inc., Bergenfield, NJ.
Abrasive aggregate shall be applied at the uniform rate of 1/4 pound per
square foot.
2.02
PROPORTIONS AND MIXES:
A.
PROPORTIONS FOR READY MIXED CONCRETE:
1.
2.
3.
4.
5.
6.
Proportioning of concrete shall be as specified in Chapter 3 of ACI 301,
latest edition.
Compressive Strength (f'c) shall be a minimum of 4,000 psi at 28 days for
exposed interior concrete floor slabs. All other concrete shall have a
minimum compressive strength of 3,000 psi at 28 days.
Air Entrainment shall be provided in all exterior concrete and all concrete
foundations. Total air content shall be four (4) to eight (8) percent by
volume as determined by ASTM C173. Air entraining admixtures shall not
be used in concrete for interior concrete slabs and flatwork.
Minimum Cement Content for concrete shall be 517 pounds per cubic yard.
Minimum cement content for all other concrete shall be 517 pounds (5 1/2
bags) per cubic yard. The use of flyash is prohibited.
Maximum Coarse Aggregate Size for concrete used for voidfill shall be 3/8
inch. Maximum coarse aggregate size for all other concrete shall be 3/4
inch.
Unit Weight of Concrete shall be normal weight.
0310-9
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
7.
Water Cement Ratio for air entrained concrete shall not exceed 0.53 by
weight.
8.
Slump shall not exceed four (4) inches for all concrete as determined by
ASTM C143. Super plasticizers approved by the Engineer may be used at
the Contractor's option to temporarily increase the slump and make the
concrete more workable.
Calcium Chloride will not be permitted in concrete mixes.
9.
B.
PROPORTIONS FOR BONDING GROUT:
1.
C.
PROPORTIONS FOR PATCHING MORTAR:
1.
D.
Patching Mortar for use in patching of surface defects shall be made of the
same materials and of approximately the same proportions as used for the
concrete, except that the coarse aggregate shall be omitted and the mortar
shall consist of not more than one part cement to 2-1/2 parts sand by damp
loose volume. White Portland cement shall be substituted for a part of the
gray Portland cement on exposed concrete in order to produce a color
matching the color of the surrounding concrete, as determined by a trial
patch. The quantity of mixing water shall be no more than necessary for
handling and placing. The patching mortar shall be mixed in advance and
allowed to stand with frequent manipulation with a trowel, without addition
of water, until it has reached the stiffest consistency that will permit placing.
PROPORTIONS FOR PLAIN PORTLAND CEMENT GROUT:
1.
2.03
Bonding Grout for use in patching of surface defects shall consist of one
part cement to one part fine sand passing the No. 30 mesh sieve mixed
with sufficient water to yield the consistency of thick cream.
Plain Grout (when and where indicated on the drawings) shall consist of a
mixture of one part Portland cement to three parts sand by weight.
SOURCE QUALITY CONTROL:
A.
READY MIXED CONCRETE shall be batched, mixed and transported in
accordance with ASTM C94, "Specifications for Ready-Mix Concrete". Plant
equipment and facilities shall conform to the "Check List for Certification of
Ready-Mixed Concrete Production Facilities" of the National Ready-Mixed
Concrete Association.
B.
CONTROL OF ADMIXTURES shall be in accordance with Section 7.3 of ACI 301
latest edition.
C.
TEMPERING AND CONTROL OF MIXING WATER shall be in accordance with
Section 7.5 of ACI 301 latest edition.
0310-10
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
D.
TEMPERATURE CONTROL of ready-mixed concrete shall be in accordance with
Section 7.6 of ACI 301 latest edition.
PART 3.00 - EXECUTION
3.01
3.02
PREPARATION AND EXAMINATION OF SURFACES:
A.
PREPARATION OF FORM SURFACES: All form surfaces shall be prepared in
accordance with Section 4.4 of ACI 301 latest edition. All form surfaces shall be
coated with specified coating material in accordance with the manufacturer's
instructions prior to installation of reinforcing steel.
B.
PREPARATION BEFORE PLACING: Preparation before placing shall conform to
the requirements of Section 8.1 of ACI 301 latest edition.
C.
PREPARATION OF SUBGRADE FOR SLABS ON GROUND: Preparation of
subgrade for slabs on ground shall conform to the requirements of Section 11.2 of
ACI 301 latest edition.
D.
SETTING OF EDGE FORMS AND SCREEDS: Edge forms and intermediate pipe
screeds spaced not more than 12 feet on center shall be accurately set to produce
the designated elevations and contours of the finish surface, and shall be
sufficiently strong to support vibrating screeds or roller pipe screeds. Screeds
shall be supported at not more than eight (8) feet on center with adjustable height
steel screed chairs set in hardened concrete pads set below slab subgrade. The
concrete surface shall be aligned to the contour screeds by the use of strike-off
templates or approved compacting type screeds. When formwork is cambered,
screeds shall be set to a like camber to maintain the proper concrete thickness.
E.
VAPOR BARRIER: Vapor barrier shall be installed continuously under all slabs on
grade. Lap joints a minimum of six (6) inches.
INSTALLATION AND WORKMANSHIP:
A.
FORMWORK: Formwork shall be designed and erected in accordance with the
requirements of Section 4.1 and 4.2 of ACI 301, latest edition. The use of steel
framed panel forms will not be permitted on exposed concrete without a smooth
form liner that will eliminate surface irregularities. One sided forms for walls will
not be permitted. Over excavated foundations shall be edge formed.
B.
JOINTS AND EMBEDDED ITEMS:
1.
2.
Construction Joints shall conform to the requirements of Section 6.1 of ACI
301 latest edition.
Crack Control Joints shall be installed as detailed and located on the
drawings.
0310-11
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
3.
4.
5.
C.
PLACING OF CONCRETE:
1.
2.
3.
D.
Saw Cut Joints: Saw cut joints shall be cut a minimum of 3/6 inch wide
with
“soft-cut” blades. Saw cutting shall be timed properly with the set of the
concrete. Cutting shall be started as soon as the concrete has hardened
Sufficiently to prevent aggregates from being dislodged by the saw, and
Shall be completed before shrinkage stresses become sufficient to produce
cracking. Saw cut depth shall be one third of slab thickness. Half of
reinforcing steel shall be removed for three (3) inches on each side of
sawed
joints.
Expansion Joints shall be installed as detailed and located on the
drawings. Unless otherwise detailed on the drawings, 1/4 inch thick
expansion joints shall be installed where concrete work butts vertical
surfaces including walls. Top of edge expansion joints shall be recessed
one half inch below slab surface with removable plastic filter caps where
expansion joints are to receive caulking or sealant.
Embedded Items including sleeves, inserts and anchors shall be accurately
positioned and anchored against displacement.
Conveying of Concrete shall conform to the requirements of Section 8.2 of
ACI 301 latest edition. Concrete truck traffic will not be permitted over
reinforcing steel or vapor barrier. Concrete buggy traffic over reinforcing
steel and vapor barrier will be permitted only on approved ramps and
runways.
Depositing of Concrete shall conform to the requirements of Section 8.3 of
ACI 301 latest edition. Mixing and placing of concrete for slabs shall be
carefully coordinated with finishing. Concrete shall not be placed on the
subgrade or forms more rapidly than it can be spread, straightedged and
darbied or bull floated. These operations must be performed before
bleeding water has an opportunity to collect on the surface. To obtain good
surfaces and avoid cold joints, the size of finishing crews shall be planned
with due regard for the effects of concrete temperature and atmospheric
conditions on the rate of hardening of the concrete. Concrete in slabs shall
be thoroughly consolidated.
Internal vibration shall be used along the bulkheads of slabs on grade.
Consolidation of slabs shall be obtained with vibrating screeds, roller pipe
screeds, internal vibrators, or other approved means.
Bonding of new concrete to hardened concrete at construction joints shall
be accomplished by dampening (but not saturating) the existing surface
and coating it with a neat cement grout immediately prior to placing of new
concrete. Joints in concrete flatwork shall not be bonded.
REMOVAL OF FORMS:
1.
Forms Not Supporting Weight of concrete may be removed as soon as
concrete has hardened sufficiently to resist damage from removal
0310-12
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
operations. Forms shall be removed from surfaces that are to receive a
smooth rubbed finish as soon as practical in order to facilitate rubbing
procedure.
E.
FINISHING OF FORMED CONCRETE SURFACES:
1.
2.
3.
F.
Rough Form Finish: All formed concrete surfaces permanently in contact
with earth or other surfaces totally concealed in the completed structure
shall receive a rough form finish as specified in Section 10.2.1 of ACI 301
latest edition.
Smooth Rubbed Finish: All formed concrete surfaces that are exposed to
view in the finished structure shall receive a smooth rubbed finish of
uniform color in addition to a smooth form finish as specified in Section
10.3.1 and Section 10.2.2 of ACI 301 latest edition respectively. If a
uniform color acceptable to the Engineer is not obtained, concrete shall be
coated with Thoroseal and/or Thorosheen as manufactured by Thoro
System Products, Inc., Miami, Florida in accordance with the
manufacturer's instructions as directed by the Engineer. Surfaces shall be
rubbed immediately after completion of curing.
Struck and Floated Finish: Tops of walls or buttresses, horizontal offsets
and similar unformed surfaces occurring adjacent to formed surfaces shall
be struck smooth after concrete is placed and shall be floated to a texture
reasonably consistent with that of the formed surfaces. Final treatment on
formed surfaces shall continue uniformly across the unformed surfaces.
FINISHING OF CONCRETE SLABS:
1.
2.
Troweled Finish: All interior exposed concrete slabs shall have a troweled
finish. After the concrete has been placed, consolidated, struck off, and
leveled, the concrete shall not be worked further until ready for floating.
Floating shall begin when the water sheen has disappeared and when the
surface has stiffened sufficiently to permit the operation. During or after the
first floating, planeness of surface shall be checked with a ten (10) ft.
straightedge applied at not less than two different angles. All high spots
shall be cut down and all low spots filled during this procedure. The slab
shall then be refloated immediately to a uniform sandy texture. It shall next
be power troweled and finally hand troweled. The first troweling after
power floating shall produce a smooth surface which is relatively free of
defects but which may still show some trowel marks. Additional trowelings
shall be done by hand after the surface has hardened sufficiently. The final
troweling shall be done when a ringing sound is produced as the trowel is
moved over the surface. The surface shall be thoroughly consolidated by
the hand troweling operations. The finished surface shall be essentially
free of trowel marks and uniform in texture and appearance.
Broomed Finish: All exterior concrete slabs and sidewalks shall have a
broomed finish. After the concrete has been placed, consolidated, struck
0310-13
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
off and leveled, the concrete shall not be worked further until ready for
floating. Floating shall begin when the water sheen has disappeared and
when the surface has stiffened sufficiently to permit the operation. During
or after the first floating, planeness of surface shall be checked with a ten
(10) foot straightedge applied at not less than two different angles. All high
spots shall be cut down and all low spots filled during this procedure. The
slab shall then be refloated immediately to a uniform sandy texture. It shall
then be given a uniform medium coarse transverse scored texture by
drawing a broom across the surface. All broom marks shall be in same
direction at right angle to longest slab edge.
G.
CURING: Curing procedures shall be applied immediately after placing and
finishing of concrete. Concrete shall not be left overnight without curing.
1.
2.
3.
H.
Footings and Foundations: Liquid curing compound applied in accordance
with the manufacturer's written instructions shall be applied to all footings
and foundations.
Concrete Flatwork: Concrete flatwork shall be cured with liquid curing
compound applied in accordance with the manufacturer's written
instructions.
Formed Surfaces: Formed surfaces shall be cured by keeping forms
continuously wet. If forms are removed sooner than seven days after
placing concrete, curing shall be continued as follows. Formed surfaces
that are exposed in the finished structure shall be cured by direct
application of absorptive mats or fabrics kept continuously wet.
REPAIR OF SURFACE DEFECTS:
1.
2.
All defects in concrete work including honeycombed concrete and tie holes
shall be prepared and patched as hereinafter specified.
Preparation of Defects:
a.
b.
3.
Honeycombed concrete and other defective concrete shall be
removed down to sound concrete. If chipping is necessary, the
edges shall be perpendicular to the surface or slightly undercut. No
featheredges will be permitted.
Tie holes shall be emptied and cleaned.
Patching Procedure:
a.
b.
c.
Thoroughly dampen area to be patched and surrounding area for at
least six (6) inches to prevent absorption of water from the patching
mortar.
After surface water has evaporated from the area to be patched,
bonding grout shall be well brushed into the surface.
When the bonding grout begins to lose the water sheen, the
premixed patching mortar shall be applied. The mortar shall be
thoroughly consolidated into place and struck off so as to leave the
0310-14
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
d.
4.
Floor Construction Joints and Crack Control Joints:
a.
b.
I.
3.03
patch slightly higher than the surrounding surface. To permit initial
shrinkage, it shall be left undisturbed for at least one hour before
being finally finished. Metal tools shall not be used in finishing a
patch in a formed wall which will be exposed.
The patched area shall be kept damp for seven days.
Joints that have spalled edges or are otherwise damaged shall be
patched with an epoxy patching compound as directed by the
Engineer.
Patching work shall be performed in strict accordance with the
material manufacturer's written instructions.
MANUFACTURER'S INSTRUCTIONS: All manufactured items and materials shall
be installed in strict accordance with the manufacturer's written instructions. The
manufacturer's instructions shall be kept on the jobsite at all times for immediate
reference.
FIELD QUALITY CONTROL:
A.
TESTING AGENCY: The Contractor shall employ an independent testing agency
suitable to the Engineer to perform testing services hereinafter specified. Costs of
testing services shall be solely borne by the Contractor. The testing agency shall
meet the requirements of ASTM E329.
B.
TESTING SERVICES:
1.
2.
The testing agency shall perform the following services:
a.
Preparation of mix designs for each type or class of concrete
required for the project. Each mix design shall be represented by at
least five cylinder compression tests at 28 days. Each mix design
shall include gradation tests for each type aggregate contained in
the mix.
b.
Compressive strength tests of field molded concrete test cylinders
in accordance with ASTM C39.
The testing agency or the Contractor shall perform the following services:
a.
b.
c.
Sample fresh concrete for concrete compressive test cylinders in
accordance with ASTM C172.
Mold and cure concrete compressive test cylinders in accordance
with ASTM C31.
Determine slump of concrete sample for each strength test and
whenever consistency of concrete appears to vary in accordance
0310-15
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
d.
with ASTM C143.
Determine the air content of each concrete sample for each
strength test in accordance with ASTM C231, ASTM C173 or ASTM
C138.
C.
CONCRETE COMPRESSIVE STRENGTH TESTS: At least one compressive
strength test shall be made for each 50 cubic yards or fraction thereof, of each mix
design of concrete placed in any one day. Each strength test shall consist of four
test cylinders. One cylinder shall be tested at seven days for information only.
Two cylinders shall be tested at 28 days for record and acceptance. The
remaining cylinder shall be held in reserve in the event that one of the record
cylinders shows evidence of improper sampling, molding or testing. In this event,
the reserve cylinder shall be tested as a record cylinder. Unneeded reserve
cylinders may be discarded. Compressive strength tests shall be made in
accordance with the requirements of ASTM C39.
D.
MARKING OF COMPRESSIVE STRENGTH TEST CYLINDERS: Compressive
test cylinders shall be marked with the following information as a minimum:
1.
2.
3.
4.
5.
6.
7.
Test number.
Date that cylinder was made.
Name of pour (i.e. wall, floor slab, etc.).
Location of pour, preferably by column line designation.
Slump in inches.
Air content in percent.
Name of person who made sample.
The above information shall be affixed to each test cylinder before it is sent to the
laboratory for testing.
E.
TEST REPORTS:
1.
Compressive Strength Test Reports shall contain the following information
as a minimum:
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
Name and location of project.
Date of report.
Date sampled.
Name of person making sample.
Date cylinder received by laboratory.
Specified 28 day strength.
Air content.
Slump.
Test number.
Name and location of pour.
Type of curing.
0310-16
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084
l.
m.
n.
o.
2.
3.04
Date tested.
Age in days.
Compressive strength.
Certification statement.
Certification: Each test report, including mix designs, shall contain a
certification by the testing agency as to whether or not data contained in
the report complies with the project specifications.
CLEANING:
A.
EXCESS CONCRETE and concrete splatter shall be cleaned from all adjacent
surfaces, materials and equipment. Proper care shall be taken to prevent damage
from cleaning operations.
B.
CONCRETE FLOORS shall be swept and washed with soap and water
immediately prior to application of floor finish or final inspection.
C.
EXTERIOR CONCRETE SLABS shall be swept and cleaned of all debris and mud
stains immediately prior to final inspection.
D.
EXTERIOR CONCRETE WALLS shall be cleaned of mud stains and discoloration
immediately prior to final inspection.
E.
CONSTRUCTION DEBRIS including form materials and curing paper shall be
removed by the Contractor from site after completion of concrete work.
F.
WASH DOWN of concrete trucks will be permitted at only one location designated
for such purpose. After completion of concrete work, debris resulting from wash
down shall be removed from the site by the Contractor.
(End of Section)
0310-17
2012.01
L.B. Smith & Associate, P.A. • 1501 Charlotte Ave. • P.O. Box 784 • Monroe, N.C. 28111-0784 • (704)289-5168 • FAX (704)283-4084