CS S2200 C

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C
ONSTRUCTION
S
TANDARDS

S
ECTION
2200

C
ONCRETE


Draft for City Council and Public Review

5/16/2011

Constructio
n Standards


Concrete


2200
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of
26




Part 1:

General

1

A.

Scope

2

1.

This section shall govern the performance of all work necessary for construction
3

of cast
-
in
-
place concrete structures for inlets, manholes, junction boxes, head
4

walls, and incidental structures.

Construction of concrete street pavements shall

5

conform to Oklahoma Department of Transportation 2009 Standard
6

Specifications and Associated American Concrete Institute Standards.

7

a)

2.

The Contractor shall guarantee that concrete of the specified compressive
8

strength is incorporated in the structures and

that the responsibility for
9

producing the required grades of concrete is assumed by the Contractor.
10

Should the average strengths shown by test cylinders fall below the strengths
11

required, the City of Stillwater may require any or all of the following cha
nges:
12

amount of cement; grading of aggregate, or ratio of the water to the cement
13

used. If the tests disclose that the strength of the concrete is insufficient for
14

the structure as built, the City of Stillwater may condemn the part of any
15

structure in wh
ich concrete of insufficient strength has been placed and the
16

Contractor shall r
eplace all in
-
place concrete whose representative cylinder
17

fails a strength test.

18

b)

Concrete shall conform to the applicable requirements of
2009
ODOT
19

Standard Specifications
-
Se
ction 70
0

Materials
, or most current edition

and
20

appropriate ACI Standard Specifications
, most current edition
.

21


22

2200.2

MATERIALS

23

A.

Cement

24

1.

All cement used in the work shall be a standard brand of portland cement
25

and shall comply with the cement ASTM C
150 Standard Specifications for "Air
-
26

Entraining Portland Cement". The cement shall be Type I.


27

2.

All cement hauled to the job shall be in original unopened containers, bags
28

or sacks showing the brand name of the manufacturer. Only one brand of
29

cement shal
l be used in any individual structure. Cement reclaimed by cleaning
30

bags or cement that has leaked from containers shall not be used. Cement shall
31

be used in the sequence of shipments received, unless otherwise directed.

32

3.

Different brands, grades or type
s of cement shall be stored separately. All
33

cement shall be stored in such a manner as to permit easy access for proper
34

inspection and identification of each shipment, in a suitable weather tight
35

building that will protect it from dampness and deteriorati
on. Packages of
36

cement which have become partially set, or contain any lumps or caked cement
37

Construction Standards

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Draft for City Council and Public Review

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Construction Standards


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shall be rejected; and, in no instance will any portion of a bag of damaged or
1

faulty cement be used.

2

2.

B.

Aggregates

3

a)

1.

All aggregates used shall conform to the re
quirements of ASTM C33
4

Specifications for "Concrete Aggregate", unless otherwise indicated on the
5

drawings or directed by the City of Stillwater.

6


7

a.

and manufactured sand
b.

c.

2.

Sampling and testing: Sampling
8

and testing shall be in accordance with t
he latest revision of the AASHTO
9

Methods.

10

Sampling

................................
...........


.....

T
-
2

11

Sieve Analysis

................................
..


...

T
-
27

12

Material Passing No. 200

..................


...

T
-
11

13

Organic Impurities

.............................


...

T
-
21

14

Clay Lumps and Friable Particles
T
-
112 modified

15

Coal and Lignite

................................
..

T
-
113

16

Mortar and Tensile Strength

.................

T
-
35

17


18

3.

Storage: Aggreg
ate shall be stored in a manner that will allow good
19

drainage and will insure that the aggregate is kept free of foreign matter. Sites
20

for stock piles shall be graded and cleaned prior to storing materials. Aggregate
21

from different sources shall be store
d in separate stock piles. Care shall be
22

taken to prevent segregation; material which becomes segregated to the extent
23

that it no longer satisfies the grading requirements shall be combined to satisfy
24

such requirements before being used in concrete.

25

C.

Wa
ter

26

Water used in mixing concrete shall be clean, clear, and free from deleterious amounts of acids,
27

alkalis, oil, salt, organic materials or any other substances injurious to the finished concrete.
28

Water from City water system may be accepted without bein
g tested. Water from other sourses
29

shall not be used until tested and approved. Testing of water shall be in accordance with
30

AASHTO Method T
-
26.

31

D.

Admixtures

32

1.

Air
-
entraining admixtures shall conform to ASTM Specifications C
-
260.

33

2.

Set
-
control admixtu
re: Set controlling agents shall conform to ASTM C
34

494, as follows:

35

a.

Type A, Water Reducing

36

b.

Type B, Retarding.

37

c.

Type C, Accelerating.

38

d.

Type D, Water
-
Reducing and Retarding.

39

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e.

Type E, Water
-
Reducing and Accelerating.

1

3.

Other admixtures: Other ad
mixtures, unless specifically called for, shall
2

be used only with the written approval of the City of Stillwater and shall be used
3

in accordance with the manufacturer's instructions and recommendations.

4

3.

3.

Fly Ash

5

a)

Use of fly ash or other cement subsitutes
shall conform to ODOT Standard
6

Specification Section 702 Supplementary Cementitious Materials.

7

E.

F.

Reinforcing Steel

8

1.

Reinforcing bars (rebar): All reinforcing bars shall be rolled from new
9

billets and shall conform to the ASTM A615 Specifications f
or Billet
-
Steel Bars
10

for Concrete Reinforcement, and shall be of the Grade 60 unless otherwise
11

specified. Unless otherwise shown, all reinforcing bars shall be deformed and
12

shall conform to the requirements of the ASTM A615 specifications for minimum
13

rein
forcement. The deformed bars used shall have a net sectional area at all
14

points equivalent to that of plain bars of equal nominal size. Twisted steel bars
15

shall not be used.

16

2.

Supports for reinforcement: Reinforcement supports shall be bolsters,
17

chair
s, spacers, and other devices for spacing, supporting, and fastening
18

reinforcements in place.

19

a.

Wire bar type supports shall comply with CRSI recommendations, unless
20

otherwise indicated. Do not use wood, brick, or concrete block.

21

b.

Sand plates or horizo
ntal runners shall be used where base material will
22

not support chair legs for slabs on grade.

23

c.

Either hot
-
dip galvanized, plastic protected or stainless steel protected
24

legs shall be used for exposed
-
to
-
view concrete surfaces, where legs of
25

supports are

in contact with forms.

26

d.

Tie wire: Tire wire sixteen (16) gauge minimum and in sufficient quantity to
27

hold reinforcement accurately in place during concrete placement operations.

28

e.

Welded steel wire fabric: Fabric shall conform to the requirements of
29

ASTM A185 and shall be of the size and space opening as designated on the
30

plans.

31

3.

Fabrication:

32

a.

General: Reinforcing bars shall be fabricated conforming to required
33

shapes and dimensions, with fabrication tolerances complying with CRSI
34

"Manual of Sta
ndard Practice." In case of fabricating errors, the Contractor
35

shall not rebend or straighten reinforcement in a manner that will injure or
36

weaken the material.

37

b.

Unacceptable materials: Reinforcement with any of the following defects
38

will not be permi
tted in the work:

39

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1)

Bar lengths, depths and bends exceeding specified fabrication
1

tolerances.

2

2)

Bend or kinds not indicated on drawings or final shop drawings.

3

3)

Bars with reduced cross
-
section due to excessive rusting or other
4

cause.

5

c.

Identification:

Reinforcing bars shall be tied in bundles and tag with
6

weatherproof tags showing shop drawing numbers.

7

b)

Splicing: Provide a minimum of 35 bar diameters of lap length
.

8

G.

Forms

9

1.

Forms for exposed concrete: Form work for exposed concrete surfaces
10

shall b
e high
-
density overlay plyform Class I or II. Panels shall be APA grade
-
11

trade
-
marked and meet requirements of the latest edition of U.S. Product
12

Standard PSI. Overlay shall not stain the surface of the architectural concrete.
13

Full sheet sizes shall be use
d to minimize number of joints and to conform to
14

joint system shown on drawings. Form material shall be of sufficient thickness
15

to withstand pressure of newly placed concrete without bow or deflection
16

(minimum 3/4 inch).

17

2.

Forms for unexposed concrete:
Concrete surfaces, which will be
18

unexposed in the finished structure, shall be formed with plywood, lumber,
19

metal, or other acceptable material. Lumber shall be dressed on at least 2
20

edges and 1 side for tight fit, tongue and grooved, free from loose knot
s and of
21

such moisture content as to prevent free absorption of moisture.

22

3.

Form coatings : Commercial formulation form coating compounds shall be
23

provided will not bond with, stain, nor adversely affect concrete surfaces, and
24

will not impair subsequent
treatment of concrete surfaces requiring bond or
25

adhesion, nor impede the wetting of surfaces to be cured with water or curing
26

compounds. Release agent shall be used in strict accordance with
27

manufacturer's recommendations.

28

4.

Vinyl foam tape: Vinyl foa
m tape shall be 3/4" x 1/8" adhesive backed
29

closed cell tape.

30

5.

Form accessories: Only form ties, anchors, and hangers of sufficient
31

strength to completely resist displacement of forms due to construction loads
32

and the depositing of concrete shall be used
. Tie
-
and
-
spreader type form ties
33

designed so that no metal will be within one inch of any surface when forms are
34

removed shall be used. Where concrete surfaces are exposed to view, the
35

Contractor shall not use form ties which, when removed, will leave a

depression
36

larger than one (1) inch in diameter. The Contractor shall use water seal ties in
37

concrete exposed to hydrostatic pressure which conform to ACI 301 and 347.

38

a.

Metal inserts shall be used for anchorages of materials or equipment to
39

concrete co
nstruction, not supplied by other trades and as required for the
40

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work. Threaded inserts of malleable cast iron, furnished complete with full
-
1

depth bolts to the proper size shall be used unless otherwise noted.

2

b.

Adjustable wedge inserts of malleable cast

iron, complete with bolts, nuts
3

and washers, and bolt size, shall be used.

4

c.

Screen chairs: Metal or wood screen chairs shall not be used.

5

d.

Corner chamfer: Chamfers shall be mill run white pine solid material or
6

preformed PVC at all exposed corners

of columns, walls and beams.

7

H.

Concrete Curing Compounds

8

1.

Absorptive cover: Burlap cloth shall be made from jute or kenaf, weighing
9

approximately 9 oz. per sq. yd., complying with AASHTO M 182, Class 3.

10

2.

Moisture
-
retaining cover: Moisture retaining

covers shall be one of the
11

following, complying with ASTM C 171.

12

a.

Waterproof paper.

13

b.

Polyethylene film.

14

c..

Polyethylene
-
coated burlap.

15

3.

Membrane
-
forming curing compound: Membrane forming curing
16

compounds shall conform to ASTM C 309, Type I with wh
ite fugitive dye unless
17

other type acceptable to the City of Stillwater.

18

4.

Liquid curing, sealing, hardening compound: The following list of
19

materials is not intended to be a complete list of materials and work required but
20

a guide to the type, quality,
and finish required for various surfaces. The list of
21

products below is intended only to set a standard of quality.

22

Product



Manufacturer

23

Eucocure



Euclid Chemical Co.

24

Masterseal



Master Builders

25

Polyclear



Upco Chemical/USM Corp.

26

Dress & Seal



L & M

Construction
27

Chemicals

28

Triple Seal



Protex Industries

29

Clear Bond



Guardian Chemical Co.

30

Cure & Seal



Symons Corporation

31

Kure
-
N
-
Seal



Sonneborn Building Products

32


33

a.

Special notes:

34

1)

Curing compounds containing oil or wax shall not be used. Allow concre
te
35

to thoroughly dry following rain. Use form release agents which will not
36

transfer to the concrete.

37

I.

Water Stops

38

Construction Standards

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Provide 3
-
1/4" polyvinyl chloride (PVC) water stops at construction joints and other joints of
1

type shown on drawings.

2

J.

Preformed Expan
sion Joint Fillers

3

Preformed expansion joint fillers shall conform ASTM D
-
1751, and be non
-
extruding and
4

resilient type.

5

K.

Radius Former

6

Radius former shall be PVC.

7


8

L. Flowable Fill

9

1.

Specify strength limitations to allow for diggable flowable concrete.

10

2.

Flowable Fill admixture shall be provided with manufacturers instructions regarding
11

installation requirements and strength limitations.

12

2200.3

QUALITY ASSURANCE

REQUIREMENTS

13

4.

Submittals

14

a)

The Contractor shall furnish, to the City of Stillwater, the certif
icates and test
15

results described below. The City of Stillwater may require additional tests
16

and/or verifications to insure the quality of concrete produced is as specified.

17

b)

Concrete:

18

1)

Mix design: Provide mix design formula for the materials proposed for
19

use in making concrete using the absolute volume method. The design
20

shall
include material sources, specific gravities and other pertinent data.

21

2)

Strength:

Prior to placing any concrete, the compressive strength shall be
22

verified by making three test cylin
ders using the proposed mix designs.
23

The cylinders
shall
be tested and the results provided with the mix design
24

submittal.

25

c)

Reinforcing steel:

26

1)

Comply with requirements of the latest edition of the following codes and
27

standards, except as herein modified:

28


29

A.

American Welding Society, AWS D1.4
-
1979, "Standard Welding Code
30

-

Reinforcing Steel."

31

B.

Concrete Reinforcing Steel Institute, "Recommended Practice for
32

Placing Reinforcing Bars."

33

C.

Concrete Reinforcing Steel Institute, "Manual of Standard Practice for
34

Reinfor
ced Concrete Construction."

35

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D.

American Concrete Institute, ACI 318, "Building Code Requirements
1

for Reinforced Concrete."

2

E.

ASTM A615: “Specifications for Deformed and Plain Billet
-
Steel Bars
3

for concrete Reinforcement.”

4

F.

ACI 315: "Manual of Standard Practice

for Detailing Reinforced
5

Concrete Structures."

6

G.

ASTM A185: “Specifications for Welded Steel Wire Fabric for Concrete
7

Reinforcement”.

8

d)

Formwork: Unless otherwise shown or specified, design, construct, erect,
9

maintain, and remove forms and related structure
s for cast
-
in
-
place concrete
10

work in compliance with the following:

11

1)

ACI 347: Recommended Practice for Concrete Form work.

12

2)

USPS PSI: Product Standard for Softwood Plywood Construction and
13

Industrial.

14

e)

Allowable tolerances:

15

1)

Construct form work to provide comp
leted cast
-
in
-
place concrete surfaces
16

complying with the tolerances specified in ACI 374.

17

2)

Before concrete placement, check the lines and levels of erected
18

formwork. Make corrections and adjustments to ensure proper size and
19

location of concrete members an
d stability of forming systems.

20

3)

During concrete placement, check formwork and related supports to
21

ensure that forms are not displaced and that completed work will be within
22

specified tolerances.

23

2200.4

Construction Methods

24

f)

Concrete mixing:

25

1)

Experimental con
crete mixes:

26

A.

The Contractor shall make experimental mixes prior to the placing of
27

the concrete and at any time during the progress of the work when
28

necessary to demonstrate that the concrete will meet these
29

specifications. Materials for making experiment
al mixes shall be
30

furnished by the Contractor and these materials shall be identical with
31

those intended for use in the work. The cost of the materials, as well
32

as the costs of crushing test specimens made from the experimental
33

mix, shall be borne by the
Contractor and shall be included in the price
34

bid for concrete.

35

2)

On
-
site mixing:

36

A.

General: The Contractor shall mix concrete in a batch mixer
37

conforming to requirements of the mixer manufacturer's Bureau of the
38

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Associated General Contractors of America.
Mixer shall bear the
1

manufacturer's rating plate indicating rated capacity and recommended
2

revolutions per minute; operate mixer in accordance with these
3

recommendations; and use only mixers that are equipped with a
4

suitable charging hopper, water storage
tank, water measuring device
5

and are capable of thoroughly mixing the concrete into a uniform mass
6

within the specified mixing time and of discharging the mix without
7

segregation.

8

B.

Admixtures: After approved for use, the Contractor shall dispense
9

liquid ad
mixtures by means of an automatic dispenser or similar
10

metering device; weigh or measure by volume powdered admixtures,
11

as recommended by the manufacturer; accurately measure all
12

admixtures to within plus or minus 5 percent; and shall provide suitable
13

agi
tating equipment to insure uniform distribution of ingredients.

14

C.

Mixing: The Contractor shall charge batch into the mixer so that some
15

water will enter in advance of the cement and aggregates; allow water
16

to flow into the mixer until the end of the first
25 percent of the
17

specified mixing time; provide controls to insure that the batch cannot
18

be discharged until the specified mixing time has elapsed; provide
19

controls to insure that no additional water may be added during mixing;
20

and discharge the entire ba
tch before recharging.

21

D.

Mixing time: The Contractor shall mix each batch of 2 cubic yards or
22

less for not less than 1
-
1/2 minutes, and not more than 5 minutes after
23

all ingredients are in the mixer before any part of the batch is released;
24

increase mixing

time by 15 seconds for each additional cubic yard or
25

fraction thereof; and not exceed 30 minutes total elapsed time between
26

intermingling of damp aggregates and cement to the discharge of the
27

completed mix into the forms.

28

E.

Maintenance: The Contractor shal
l keep mixer clean and replace
29

mixer pick
-
up and throw over blades when they have lost 10 percent of
30

their original depth.

31

F.

Identification: The Contractor shall provide a batch ticket for each
32

batch discharged and used in the work, indicating the project
33

i
dentification name and number, date, mix type, mix time, quantity and
34

amount of water introduced.

35

G.

Retempering: The Contractor shall mix concrete only in quantities for
36

immediate use. Discard concrete which has set; do not retemper.
37

Adding water to the m
ix at the job site shall not be permitted.

38

3)

Ready
-
mix concrete: The Contractor shall comply with the requirements
39

of ASTM C94, and as herein specified, provided quantity and rate of
40

delivery will permit unrestricted progress of the work in accordance with

41

the placement schedule. During hot weather, or under conditions
42

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contributing to rapid setting of concrete, a shorter mixing time than
1

specified in ASTM C 94 may be required. Proposed changes in mixing
2

procedures shall be accepted by the City of Stillwat
er before
3

implementation. All mixer trucks shall be equipped with water meters.
4

Plant equipment and facilities should conform to National Ready
-
Mix
5

Concrete Association "Check
-
list for Certification of Ready
-
Mixed
6

Concrete Production Facilities".

7

4)

Consiste
ncy:

8

A.

All reinforced concrete which is required to be spaded or puddled in
9

forms or around reinforcing steel shall be of such consistency that:

10

1.

All aggregates will float uniformly throughout the mass without
11

settling or segregating.

12

2.

When dropped directly
from the discharge chute of the mixer, the
13

concrete will flatten out at the center of the pile but will stand up at
14

the edges, the piling spreading from internal expansion and not by
15

flowing.

16

3.

The concrete will flow sluggishly when tamped or spaded.

17

4.

The con
crete can be readily puddled into corners and angles of
18

forms and around reinforcing steel,

19

5.

The concrete can be readily spaded to the bottom of the placement
20

or to a depth of several feet at any time within thirty (30) minutes
21

after placing.

22

B.

A desirable co
nsistency is one which results in a very slight
23

accumulation of water at the top of a layer several feet in thickness, but
24

without segregation or accumulation of laitance. If, through accident,
25

intention or error in mixing, any concrete shall vary materia
lly from the
26

consistency specified, such concrete shall not be incorporated in the
27

work but shall be discharged as waste material.

28

g)

Cast
-
in
-
place concrete:

29

1)

Form work design:

30

A.

The Contractor shall design, erect, support, brace and maintain form
31

work so that i
t will safely support vertical and lateral loads that might be
32

applied, until such loads can be supported by the concrete structure.
33

The Contractor shall carry vertical and lateral loads to ground by a
34

form work system and in
-
place construction that has at
tained adequate
35

strength for that purpose. The Contractor shall construct form work so
36

that concrete members and structures are of correct size, shape,
37

alignment, elevation, and position.

38

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B.

The Contractor shall design forms and falsework to include assumed
1

values of live load, dead load, weight of moving equipment operated
2

on Form work, concrete mix, height of concrete drop, vibrator
3

frequency, ambient temperature, foundation pressures, stresses,
4

lateral stability, and other factors pertinent to safety of st
ructure during
5

construction.

6

C.

The Contractor shall provide shores and struts with positive means of
7

adjustment capable of taking up form work settlement during concrete
8

placing operations, using wedges or jacks or a combination thereof
9

and provide trussed s
upports when adequate foundations for shores
10

and struts cannot be secured.

11

D.

The Contractor shall support form facing materials by structural
12

members spaced sufficiently close to prevent deflection; fit forms
13

placed in successive units for continuous surface
s to accurate
14

alignment, free from irregularities and within allowable tolerances; and
15

provide camber in form work as required for anticipated deflections due
16

to weight and pressures of fresh concrete and construction loads for
17

long
-
span members without in
termediate supports.

18

E.

The Contractor shall provide temporary openings in wall forms, column
19

forms and at other locations necessary to permit inspection and clean
-
20

out.

21

F.

The Contractor shall design form work to be readily removable without
22

impact, shock or dam
age to cast
-
in
-
place concrete surfaces and
23

adjacent materials.

24

G.

The Contractor shall provide form work sufficiently tight to prevent
25

leakage of cement paste during concrete placement; solidly butt joints
26

and provide backup material at joints as required to
prevent leakage
27

and fins; seal form joints with foam tape or other demonstrated
28

effective means; and provide a means to seal the bottom of forms at
29

construction joints such as foam tape or other gasket devices.

30

2)

Placing forms:

31

A.

Concrete forming shall conform

to ACI Code 347, to the exact sizes,
32

shapes, lines and dimensions shown, and as required to obtain
33

accurate alignment, location, grades, level and plumb work in finished
34

structures; provide for openings, offsets, sinkages, keyways, recesses,
35

moldings, rus
tications, reglets, chamfers, blocking screeds, bulkheads,
36

anchorages and inserts, and other features required; and use select
37

materials to obtain required finishes.

38

B.

Forms shall be installed so removal without hammering or prying
39

against concrete surfaces.

Crush plates or wrecking plates shall be
40

installed where stripping may damage cast concrete surfaces. Top
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forms for inclined surfaces shall be installed where the slope is too
1

steep or place concrete with bottom forms only. Kerf wood inserts for
2

formin
g keyways, reglets, recesses, and the like to prevent swelling
3

and assure ease of removal.

4

C.

The Contractor shall provide temporary openings where interior area of
5

form work is inaccessible for clean out, for inspection before concrete
6

placement, and for pla
cement of concrete. The Contractor shall brace
7

temporary closures and set tightly to forms to prevent loss of concrete
8

mortar and locate temporary openings on forms in as inconspicuous
9

location as possible, consistent with project requirements.

10

D.

The Contrac
tor shall form intersecting planes to provide true, clean
-
cut
11

corners, with edge grain of plywood not exposed as form for concrete.

12

E.

The Contractor shall provide openings in forms to accommodate other
13

work, including mechanical and electrical work; and accu
rately place
14

and securely support items required to be built into the form.


15

F.

The material to be used in the forms for exposed surfaces shall be
16

sized and dressed lumber or metal in which all bolt and rivet heads are
17

countersunk. In either case, a plain, s
mooth surface of the desired
18

contour shall be obtained.

19

G.

Undressed lumber may be used for backing or other unexposed
20

surfaces, except inside faces of conduits.

21

H.

Dimensions affecting the construction of subsequent portions of the
22

work shall be carefully che
cked after the forms are erected and before
23

any concrete is placed.

24

I.

Temporary openings where interior area of form work is inaccessible
25

shall be used for clean out, for inspection before concrete placement,
26

and for placement of concrete. Temporary closu
res shall be braced
27

and set tightly to forms to prevent loss of concrete mortar. Temporary
28

openings shall be located on forms in as inconspicuous location as
29

possible, consistent with project requirements.

30

J.

Intersecting planes shall be formed to provide tru
e, clean
-
cut corners,
31

with edge grain of plywood not exposed as form for concrete.

32

K.

Provide openings in forms to accommodate other work, including
33

mechanical and electrical work. Accurately place and securely support
34

items required to be built into the for
m.

35

3)

Falsework:

36

A.

The Contractor shall erect falsework and support, brace, and maintain
37

it to safely support vertical, lateral and asymmetrical loads applied until
38

such loads can be supported by in
-
place concrete structures; and
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construct falsework so that adj
ustments can be made for take
-
up and
1

settlement.

2

B.

The Contractor shall provide wedges, jacks, or camber strips to
3

facilitate vertical adjustments; carefully inspect falsework and form
4

work during and after concrete placement operations to determine
5

abnormal

deflection or signs of failure; and make necessary
6

adjustments to produce work of required dimensions.

7

4)

Forms for exposed concrete:

8

A.

The Contractor shall drill forms to suit ties used and to prevent leakage
9

of concrete mortar around tie holes and not splint
er forms by driving
10

ties through improperly prepared holes.

11

B.

The Contractor shall not use metal cover plates for patching holes or
12

defects in forms.

13

C.

The Contractor shall provide sharp, clean corners at intersecting
14

planes, without visible edges or offsets;
and back joints with extra
15

studs or girts to maintain true, square intersections.

16

D.

The Contractor shall use extra studs, walers, and bracing to prevent
17

bowing of forms between studs and to avoid bowed appearance in
18

concrete. The Contractor shall not use nar
row strips of form material
19

which will produce a bow.

20

E.

The Contractor shall assemble forms to be readily removed without
21

damage to exposed concrete surfaces.

22

F.

The Contractor shall form molding shapes, recesses and projections
23

with smooth
-
finish materials, an
d install forms with sealed joints to
24

prevent displacement.

25

5)

Corner treatment:

26

A.

The Contractor shall form exposed corners to produce square, smooth,
27

solid, unbroken lines, except as other wise shown.

28

B.

The Contractor shall form chamfers with 3/4" x 3/4" strips
, unless
29

otherwise shown, accurately formed and surfaced to produce uniformly
30

straight lines and tight edge joints. The Contractor shall extend
31

terminal edges to required limit and miter chamfer strips at changes in
32

direction.

33

C.

Unexposed corners may be for
med either square or chamfered.

34

6)

Control joints:

35

A.

Concrete shall be placed continuously so that the unit will be
36

monolithic in construction. Fresh concrete may be placed against
37

adjoining units provided the set concrete is sufficiently hard not to be
38

injur
ed thereby. Joints not indicated shall be made and located to least
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impair strength and appearance of the structure. Concrete for walls
1

shall be in place at least 2 hours before concreting beams, girders, or
2

slabs thereon. Beams, brackets, and haunches
shall be considered as
3

part of the floor system and shall be placed monolithically therewith.
4

Placement of concrete shall be at such rate that surfaces of concrete
5

not carried to joint levels will not have attained initial set before
6

additional concrete i
s placed thereon. Girders, beams, and slabs shall
7

be placed in one operation. In walls having door and window
8

openings, individual lifts shall terminate at top and bottom of opening.
9

Other lifts shall terminate at such levels as are indicated or as to
10

c
onform to structural requirements or architectural details, or both, as
11

directed.

12

7)

Water stops: The Contractor shall provide water stops in construction
13

joints as shown on the drawings. Install water stops to form a continuous
14

diaphragm in each joint; mak
e provisions to support and protect water
15

stops during the progress of the work; fabricate field joints in water stops
16

in accordance with manufacturer's print instructions; and protect water
17

stop material from damage where it protrudes from any point. No w
ood
18

device of any kind used to separate forms shall be permitted to remain in
19

the finished work.

20

8)

Provision for other trades: The Contractor shall provide openings in
21

concrete form work to accommodate work of other trades, including those
22

under separate
prime contracts (if any). Size and location of openings,
23

recesses and chases are the responsibility of the trade requiring such
24

items. The Contractor shall accurately place and securely support items
25

to be built into forms.

26

9)

Cleaning and tightening: The
Contractor shall thoroughly clean forms and
27

adjacent surfaces to receive concrete; remove chips, wood, sawdust, dirt
28

or other debris just before concrete is to be placed; and retighten forms
29

immediately after concrete placement as required to eliminate mor
tar
30

leaks.

31

10)

Form coatings:

32

A.

The Contractor shall coat form contact surfaces with form
-
coating
33

compound before reinforcement is placed; keep excess form coating
34

from accumulating in forms or to come into contact with surface which
35

will be bonded to fresh conc
rete; and apply in compliance with
36

manufacturer's instructions.

37

B.

The Contractor shall coat steel forms with a non
-
staining, rust
-
38

preventive form oil or otherwise protect against rusting. Rust
-
stained
39

steel form work is not acceptable.

40

11)

Installation of embed
ded items:

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A.

General: The Contractor shall set and build into the wood anchorage
1

devices and other embedded items required for other work that is
2

attached to, or supported by, cast
-
in
-
place concrete and use setting
3

drawings, diagrams, instructions and dire
ctions provided by suppliers
4

of the items to be attached thereto.

5

B.

Edge forms and screen strips for slabs: The Contractor shall set edge
6

forms or bulkheads and intermediate screen strips for slabs to obtain
7

required elevations and contours in the finished

slab surface and
8

provide and secure units to support types of screen required.

9

12)

Shores and supports:

10

A.

The Contractor shall comply with ACI 347 for shoring and reshoring,
11

and as herein specified.

12

B.

Remove shores and reshore in a planned sequence to avoid damag
e
13

to partially cured concrete.

14

C.

Locate and provide adequate reshoring to safely support the work
15

without excessive stress or deflection.

16

13)

Placing reinforcement:

17

A.

All reinforcement, when placed, shall be free from mill scale, loose or
18

thick rust, dirt, paint,
oil or grease, and shall present a clean surface.
19

Storage of material shall be on pallets with tarpaulin coverings to
20

prevent rust and scale.

21

B.

Bends and splices shall be accurately and neatly performed, and shall
22

conform to the ACI Manual of Standard Pract
ice for Detailing
23

Reinforced Concrete Structures and the CRSI Handbook.

24

C.

All reinforcing shall be placed in the exact position shown on the plans
25

and shall be held firmly in position by means of metal chairs, bolsters,
26

spacers, hangers or other accepted s
upports, such as wiring the bars
27

together at intersections with accepted wire ties in order that the
28

reinforcement will not be displaced during the depositing and
29

compacting of the concrete. Tie wires ends shall be turned away from
30

the exposed surfaces.

31

D.

W
hen the concrete surface will be exposed to the weather in the
32

finished structure or where rust would impair the appearance, the
33

portions of all accessories in contact with the form work shall be
34

galvanized steel or plastic.

35

E.

The placing and fastening of
reinforcement in each section of the work
36

shall be accepted by the City of Stillwater before any concrete is
37

deposited in the section.

38

F.

Care shall be taken not to disturb the reinforcement after the concrete
39

has taken its initial set.

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G.

Reinforcing steel
shall be overlapped to fully develop the reinforcing.

1

H.

Splicing bars shall be performed in accordance with ACI Code 318 for
2

minimum lap. Splice locations shall be at mid
-
span on all top bars and
3

at the supports for all bottom bars.

4

I.

The minimum coverages for

reinforcement shall be maintained as
5

stated in ACI Code 318.

6

14)

Anchors and inserts:

7

A.

Anchor bolts, castings, steel shapes, conduit, sleeves, masonry
8

anchorage, and other materials that are to be embedded in the
9

concrete shall be accurately positioned in the
forms and securely
10

anchored.

11

B.

Unless installed in pipe sleeves, anchor bolts shall have sufficient
12

threads to permit a nut to be installed on the concrete side of the form
13

or template. A second nut shall be installed on the other side of the
14

form or templa
te and the two nuts shall be adjusted so that the bolt will
15

be held rigidly in proper position.

16

C.

Inserts shall be clean when installed. After installation, surfaces not in
17

contact with concrete shall be cleaned of concrete spatter and other
18

foreign substan
ces.

19

D.

The Contractor shall coordinate the installation of all anchors and
20

inserts during forming operations. Prior to actual placement of
21

concrete, all insert and anchor locations shall be rechecked to assure
22

proper vertical and horizontal alignment.

23

E.

Care
shall be taken during placement operations so as not to alter the
24

location of any anchors or inserts.

25

F.

After screening operations are complete, the vertical and horizontal
26

alignment shall be rechecked to assure the proper location of anchors
27

and inserts.

28

G.

In the event the alignment is improper, the Contractor shall revise,
29

repair, modify, or replace any anchor or insert which is improperly
30

embedded. The cost of such work shall be borne by the Contractor.

31

15)

Pre
-
placement inspection:

32

A.

Before placing concrete,

inspect and complete the form work
33

installation, reinforcing steel, preformed joint fillers, vapor barriers,
34

water stops and items to be embedded or cast
-
in. Notify other crafts
35

involved in ample time to permit the installation of their work; cooperate
36

w
ith other trades in setting such work, as required.

37

B.

Thoroughly wet the forms immediately before placing concrete, as
38

required where form coatings are not used. Where coating is used, the
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Contractor shall with a brush or spray coating, covering the form
1

ev
enly without excess drip. Form oil which causes softening or
2

permanent staining of the concrete shall not be used.

3

C.

Soil at bottom of foundation systems is subject to testing for soil
4

bearing value by the testing laboratory. Place concrete immediately
5

aft
er approval of foundation excavations. Excavate and backfill as
6

necessary to complete the concrete work. Place concrete on
7

subgrades that are well compacted to level and true grade. Before
8

concrete is placed in areas between slabs on grade previously pl
aced,
9

recheck compaction of subgrade and if necessary, re
-
compact to avoid
10

settlement of slabs at joints. Seal extremely porous subgrades in a
11

manner approved by the City of Stillwater. Remove all ice, debris, and
12

excess water from subgrades.

13

D.

Coordinate

the installation of joint materials and moisture barriers with
14

placement of forms and reinforcing steel.

15

E.

The installation of anchors, inserts, and sleeves for electrical,
16

mechanical plumbing, heating, ventilating and air
-
conditioning work is
17

subject to th
e inspection and approval of the supervisors of the
18

particular trades involved. Finish voids in sleeves and inserts
19

temporarily with readily removable material.

20

F.

Notify the City of Stillwater 24 hours before placing concrete.

21

16)

Concrete conveying:

22

A.

General:

Handle concrete from the mixer to the place of final deposit
23

as rapidly as practicable and in a manner which will assure that the
24

specified quality of the concrete is obtained.

25

B.

Equipment: Provide conveying equipment of proper size and design
26

to insure
a continuous flow of concrete to a delivery end. Conveying
27

equipment will be subject to the City of Stillwater's approval.

28

C.

Truck mixers, agitators and non
-
agitating units and their manner of
29

operation shall conform to the applicable requirements of ASTM

C 94.

30

D.

Belt conveyors: Provide conveyors and discharge apparatus of a type
31

which will not cause segregation. Discharge long runs into a hopper.

32

E.

Chutes: Provide metal or metal lined chutes and install to a slope not
33

exceeding 1 vertical to 3 horizontal

and not less than 1 vertical to 20
34

horizontal. Chutes more than 20 feet long and chutes not meeting the
35

slope requirements may be used provided they discharge into a proper
36

hopper.

37

F.

Runways: Provide runways or other means for wheeled equipment to
38

convey
concrete to placement points. Do not support runways on
39

reinforcement, or wheel equipment over reinforcement.

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G.

Pumps: Do not pump concrete without the City of Stillwater's
1

approval. Any change in concrete mix necessitated by pumping must
2

be approved by
the City of Stillwater prior to placing concrete by this
3

method.

4

17)

Placing concrete:

5

A.

Place concrete in compliance with the practices and recommendations
6

of ACI 304, and as specified herein. Do not place any concrete until
7

the City of Stillwater has reviewed

the results of the design mix 28
-
day
8

test breaks and approval is given to proceed.

9

B.

Concrete shall be deposited so that the aggregates are not
10

segregated. Conveying concrete shall occur to prevent segregation of
11

the aggregate. Conveying shall be by belt c
onveyor, tremmie, chutes
12

or pumps. Vertical drops in excess 5 feet shall be conveyed using one
13

of these techniques. Chutes shall not be used if the slopes are greater
14

than 3:1.

15

C.

Deposit concrete in forms in horizontal layers not deeper than 24
16

inches and i
n a manner to avoid inclined construction joints. Where
17

placement consists of several layers, place each layer while preceding
18

layer is still plastic to avoid cold joints.

19

D.

Remove temporary spreaders in forms when concrete placing has
20

reached the elevation

of such spreaders.

21

E.

The concrete shall be deposited in continuous horizontal layers so that
22

no concrete will be allowed to harden and cause the formation of
23

seams or planes of weaknesses. Concrete placement shall occur at a
24

rate to keep the placed concrete

integral with the new concrete. Work
25

shall be arranged in order that each part of the work shall be placed as
26

a unit if this is possible. Where necessary to stop placing concrete, the
27

work shall be brought up in level courses and against a vertical stop

28

board.

29

F.

Consolidate concrete placed in forms by mechanical vibrating
30

equipment supplemented by hand
-
spading, rodding or tamping, so that
31

the concrete is thoroughly worked around reinforcement and
32

embedded item and into the corners of forms. Consolidate e
ach layer
33

of concrete with previously placed layers in a manner that will eliminate
34

all air or stone pockets which may cause honeycombing, pitting, or
35

planes of weakness. Where internal vibrators are used, provide
36

mechanical vibrators with a minimum frequ
ency of 7000 revolutions
37

per minute. Do not use vibrators to transport concrete. Insert and
38

withdraw vibrators at points from 18 to 30 inches apart for 5 to 15
39

seconds duration. Keep a spare vibrator on the job site during all
40

concrete operations.

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G.

Reinfo
rcing steel position shall be held continuously during concrete
1

placement.

2

H.

The placing of concrete under water, where permitted, must be done
3

by special accepted methods.

4

I.

Formed elements: Use internal vibrators, not form vibrators. When a
5

surface mortar

is to be the basis of the finish, work coarse aggregate
6

back from the forms with a suitable tool to bring a full surface of mortar
7

against the form.

8

J.

Supported elements: Use internal vibrators in elevated beams, girders
9

and brackets and along construction

joints. Consolidate elevated slabs
10

with vibrating bridge screeds, roller pipe screens or other means
11

approved by the City of Stillwater. Tamp slabs to force aggregates
12

away from surface and screen level to comply with ACI 347. After
13

screeding, do not m
anipulate concrete prior to commencing finishing
14

operations.

15

K.

Bring slab surfaces to the correct level with a straight edge and strike
16

off. Use bull floats or darbies to smooth the surface, leaving it free of
17

humps or hollows. Do not sprinkle water on the
plastic surface. Do not
18

disturb the slab surfaces prior to beginning finishing operations.

19

18)

Cold weather placement:

20

A.

Concrete placed during cold weather shall conform to ACI Code 306
-
1
-
21

90 Standard Specification for Cold Weather Concreting.


22

19)

Hot weather plac
ement:

23

A.

Concrete placed during hot weather shall conform to ACI
Standard

24

305.
1
-
06. Specification for Hot Weather Concreting.

The work shall be
25

performed entirely at the Contractor's risk.

26

20)

Bonding:

27

A.

Roughen surface of set concrete at all joints, except
where bonding is
28

obtained by use of a concrete bonding agent, and clean surfaces of
29

laitance, coatings, loose particles, and foreign matter. Roughen
30

surfaces in a manner to expose boned aggregate uniformly and to not
31

leave latence, loose particles of aggr
egate, or damaged concrete at
32

the surface.

33

B.

Prepare for bonding of fresh concrete to new concrete that has set but
34

is not fully cured, as follows:

35

1.

At joints between footings and walls and between walls and beams
36

or slabs they support, and elsewhere unless o
therwise specified
37

herein, dampen but do not saturate, the roughened and cleaned
38

surface of set concrete immediately before placing fresh concrete.

39

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2.

At joints in exposed work; at vertical joints in walls; at joints in
1

girders, beams, supported slabs and oth
er structural members; and
2

at joints designed to contain liquids; dampen, but do not saturate,
3

the roughened and cleaned surface of set concrete and apply a
4

liberal coating of neat cement grout.

5

3.

Use neat cement grout consisting of equal parts Portland ceme
nt
6

and fine aggregate by weight and not more than 6 gallons of water
7

per sack of cement. Apply with a stiff broom or brush to a minimum
8

thickness of 1/16". Deposit fresh concrete before cement grout has
9

attained its initial set.


10

4.

In lieu of neat cement
grout, bonding grout may be commercial
11

bonding agent. Apply to cleaned concrete surfaces in accordance
12

with the printed instructions of the bonding material manufacturer.

13

21)

Construction joints: Construction joints shall be located as shown on the
14

plans and

at other points as may be necessary during construction
15

provided that the location and nature of additional joints shall be accepted
16

by the City of Stillwater. In general, joints shall be located at points of
17

minimum shear, shall be perpendicular to the
principal lines of stress, and
18

shall have suitable keys having areas of approximately one
-
third (1/3) of
19

the area of the joints. When placing against a construction joint, the
20

surface of the concrete previously placed shall be thoroughly cleaned of
21

dirt,
scum, laitance or other soft material, and shall be roughened. The
22

surface shall then be thoroughly washed with clean water and covered
23

with at lease 2 inches of cement mortar, after which concreting may
24

proceed. Mortar shall be placed in a manner that w
ill not splatter forms
25

and reinforcing steel.

26

22)

Finish of concrete surfaces: All surfaces exposed to view shall be free
27

from conspicuous lines, affects or other irregularities caused by defects in
28

the forms. If for any reason this requirement is not met
, or if there are any
29

conspicuous honeycombs, the City of Stillwater may require a correction
30

of the defects by rubbing with carborundum bricks and water until a
31

satisfactory finish is obtained. Immediately after removing the forms, all
32

wires or other exp
osed metal shall be cut back of the concrete surface and
33

the depressions thus made and all honeycomb and other defects shall be
34

painted with mortar and then rubbed smooth. If the City of Stillwater
35

deems any honey comb or other defect to require such trea
tment, the
36

defective concrete shall be cut out to a depth sufficient to expose the
37

reinforcement and to afford a key for the concrete replacing the cut out.

38

23)

Curing concrete:

39

A.

Exposed surfaces of concrete shall be protected by accepted methods
40

from prematur
e drying for a period of at least seven (7) days. Curing
41

compounds, when accepted by the City of Stillwater, shall be applied
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according to the manufacturer's recommendations and shall not be
1

used on any surface against which additional concrete is to be b
onded,
2

nor on surfaces which will be painted. In dry, hot weather, forms shall
3

be removed as early as practicable and curing started immediately.
4

The City of Stillwater may require the frequent wetting of the concrete
5

and the use of means to protect it f
rom the direct rays of the sun.

6

1.

The Contractor shall protect freshly placed concrete from
7

premature drying and excessive cold or hot temperature, and
8

maintain without drying at a relatively constant temperature for the
9

period of time necessary for hydratio
n of the cement and proper
10

hardening of the concrete.

11

2.

The Contractor shall start initial curing as soon as free moisture has
12

disappeared from the concrete surface after placing and finishing
13

and weather permitting, keep continuously moist for not less than

14

72 hours.

15

3.

The Contractor shall begin final curing procedures immediately
16

following initial curing and before the concrete has dried; continue
17

final curing for at least 7 days and in accordance with ACI 301
18

procedures; and avoid rapid drying at the end of
the final curing
19

period.

20

B.

Water curing: The Contractor shall moist cure the concrete using only
21

water that is free of impurities which could etch or discolor exposed,
22

natural concrete surface. The methods are as follows:

23

1.

Keeping the surface of the concret
e continuously wet by covering
24

with water.

25

2.

Continuous water
-
fog spray.

26

3.

Covering the concrete surface with the specified absorptive cover,
27

thoroughly saturating the cover with water, and keeping the
28

absorptive cover continuously wet. Place absorptive cover

so as to
29

provide coverage of the concrete surfaces and edges, with a 4 inch
30

lap over adjacent absorptive covers.

31

C.

Moisture Retaining Cover: The Contractor shall provide moisture
32

retaining cover curing as follows: Cover the concrete surfaces with the
33

specif
ied moisture
-
retaining cover for curing concrete, placed in the
34

widest practicable width with sides and ends lapped at least 3" and
35

sealed by waterproof tape or adhesive. Immediately repair any holes
36

or tears during the curing period using cover material
and waterproof
37

tape.

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D.

Liquid membrane cover: The Contractor shall provide liquid
1

membrane curing as follows:

2

1.

Apply the specified membrane
-
forming curing compound to damp
3

concrete surfaces as soon as the water film has disappeared.
4

Apply uniformly in a 2
-
c
oat continuous operation by power spray
5

equipment in accordance with the manufacturer's directions. Re
-
6

coat areas which are subjected to heavy rainfall within 3 hours after
7

initial application. Maintain the continuity of the coating and repair
8

damage to
the coat during the entire curing period.

9

2.

Do not use membrane curing compounds on surfaces which are to
10

be covered with a coating material applied directly to the concrete
11

or with a covering material bonded to the concrete, such as other
12

concrete, liquid f
loor hardener, waterproofing, dampproofing,
13

membrane roofing, flooring, painting, and other coatings and finish
14

materials, unless otherwise acceptable to the City of Stillwater.

15

E.

Curing formed surfaces: The Contractor shall cure formed concrete
16

surfaces, in
cluding the undersides of girders, beams, supported slabs
17

and other similar surfaces by moist curing with the forms in place for
18

the full curing period or until forms are removed. If forms are removed
19

prior to specified curing period, continue curing by o
ne of the methods
20

specified in "Curing Unformed Surfaces".

21

F.

Curing unformed surfaces: The Contractor shall immediately after
22

finishing operation is complete, commence curing unformed surfaces
23

by one of the following methods:

24

1.

Continuously sprinkle or pond s
urface with water. Use this method
25

for footings only.

26

2.

Cover surface with 2 inches of moist sand. Keep sand moist
27

throughout the curing period. Use this method for footings only.

28

3.

Cover surface with moist fabric. Keep fabric moist and in direct
29

contact w
ith surface so that a film of water remains on the surface
30

throughout the curing period. This method may be used on all
31

concrete surfaces.

32

4.

Cover surface with curing paper. Lap sides and ends at least 3
33

inches and seal with tape. This method may be used
on all
34

concrete surfaces.

35

5.

Apply a uniform coat of liquid curing compound in accordance with
36

manufacturer's recommendations. This method may be used on all
37

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concrete surfaces except those scheduled to receive bonded
1

materials. Do not use this method in hot

weather.

2

G.

Temperature of concrete during curing:

3

1.

When the atmospheric temperature is 40° F and below, the
4

Contractor shall maintain the concrete temperature between 50° F
5

and 70° F continuously throughout the curing period. When
6

necessary, make arrangemen
ts before concrete placing for heating,
7

covering, insulating, or housing, as required to maintain the
8

specified temperature and moisture conditions, continuously for the
9

concrete curing period. Do not use combustion the first 24 hours of
10

curing without ta
king precautions to prevent exposure of the
11

concrete to exhaust gases. Provide cold weather protection
12

complying with the requirements of ACI 306.

13

2.

When the atmospheric temperature is 80° F, and above or during
14

other climatic conditions which will cause to
o rapid drying of the
15

concrete, the Contractor shall make arrangements before the start
16

of concrete placing for the installation of wind breaks or shading,
17

and for fog spraying, wet sprinkling, or moisture retaining covering.
18

Protect the concrete continuo
usly for the concrete curing period.
19

Provide hot weather protection complying with the requirements of
20

ACI 305. Maintain temperature as uniformly as possible, and
21

protect from rapid atmospheric temperature changes. Avoid
22

temperature changes in concrete
which exceed 5 degrees F. in any
23

one hour and 50 degrees F. in any 24 hour period.

24

H.

Protection from mechanical injury:

25

1.

During the curing period, protect concrete from damaging
26

mechanical disturbances including load stresses, heavy shock,
27

excessive vibratio
n, and from damage caused by rain or flowing
28

water. Protect all finished concrete surfaces from damage by
29

subsequent construction operations. Do not allow any traffic
30

(except for curing purposes) on the concrete surfaces until the
31

concrete has attained 6
0% of its 28
-
day strength.

32

24)

Removal of forms: Forms shall be removed in such manner as to ensure
33

the complete safety of the structure. No forms shall be removed except
34

with the express permission of the City of Stillwater. In general,
35

acceptance will b
e based on the following:

36

A.

Forms on ornamental work, railings, parapets and vertical surfaces
37

which do not carry loads and which will be exposed in the finished
38

work shall be removed within twenty
-
four (24) hours to forty
-
eight (48)
39

hours after placing, as
long as the temperature has been above 50° F
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the entire duration and the concrete hardness is such that the form
1

removal will not damage the surface.

2

B.

Form work supporting weight of concrete, such as beam soffits, joists,
3

and slabs and other structural elem
ents shall not be removed in less
4

than fourteen (14) days and not until concrete has attained the design
5

minimum twenty
-
eight (28) day compressive strength. Determine
6

potential compressive strength of in
-
place concrete location or
7

members under the least
favorable conditions prevailing for any portion
8

of the concrete.

9

C.

Girder, beam and joint soffit forms shall remain in place with adequate
10

shoring underneath, and no construction load shall be supported upon
11

nor any shoring removed from any part of the stru
cture under
12

construction until that portion of the structure has attained sufficient
13

strength to support safely its weight and the loads placed thereon.


14

D.

Form facing material may be removed four (4) days after placement,
15

only if shores and other vertical s
upports have been arranged to permit
16

removal of form facing material without loosening or disturbing shores
17

and supports.

18

25)

Re
-
use of forms:

19

A.

The Contractor shall form lumber which is to be used a second time
20

shall be free from bulge or warp and shall be thor
oughly cleaned and
21

repaired. Split, frayed, delaminated or otherwise damaged form facing
22

material will not be acceptable. The Contractor shall apply new form
23

coating compound material to concrete contact surfaces as specified
24

for new form work.

25

B.

When forms

are extended for successive concrete placement, the
26

Contractor shall thoroughly clean surfaces, remove fins and latence,
27

and tighten forms to close all joints. Align and secure joints to avoid
28

offsets. Do not use "patched" forms for exposed concrete surf
aces,
29

except as acceptable to the Owner's Representative.

30

26)

Concrete surface repairs:

31

A.

Patching defective areas

32

1.

The Contractor shall repair and patch all defective areas with
33

cement mortar immediately after removal of forms, but only when
34

directed by the City

of Stillwater.

35

2.

The Contractor shall cut out honeycomb and rock pockets, down to
36

concrete but, in no case, to a depth of less than 1 inch. In no case
37

shall reinforcing metal be cut into. Make edges of cuts
38

perpendicular to the concrete surface. Before pla
cing the cement
39

mortar, thoroughly clean, dampen with water, and brush
-
coat the
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area to be patched with neat cement grout. Proprietary patching
1

compounds may be used when acceptable to the City of Stillwater.

2

3.

For exposed
-
to
-
view surfaces, the Contractor s
hall blend white
3

portland cement and standard portland cement so that, when dry,
4

the patching mortar will match the color of the surrounding
5

concrete. Provide test areas at inconspicuous location to verify
6

mixture and color match before proceeding with th
e patching.
7

Compact mortar in place and strike off slightly higher than the
8

surrounding surface.

9

4.

The Contractor shall fill holes extending through concrete by means
10

of a plunger
-
type gun or other suitable device from the least
11

exposed face, using a flush
stop held at the exposed face to insure
12

complete filling.

13

B.

Repair of formed surfaces

14

1.

The Contractor shall repair of exposed
-
to
-
view formed concrete
15

surfaces where possible, that contain defects which adversely
16

affect the appearance of the finish. Remove an
d replace the
17

concrete having defective surfaces if the defects cannot be repaired
18

to the satisfaction of the City of Stillwater. Surface defects, as
19

such, include color and texture irregularities, cracks, spalls, air
20

bubbles, honeycomb, rock pockets, and

holes left by the rods and
21

bolts; fins and other projections on the surface; and stain and other
22

discoloration that cannot be removed by cleaning.

23

2.

The Contractor shall repair concealed formed concrete surfaces,
24

where possible, that contain defects that ad
versely affect the
25

durability of the concrete. If defects cannot be repaired, remove
26

and replace the concrete having defective surfaces. Surface
27

defects, as such, include cracks in excess of 0.01 inch wide, cracks
28

of any width and other surface deficienc
ies which penetrate to the
29

reinforcement or completely through non
-
reinforced sections,
30

honeycomb, rock pockets, holes left by tie rods and bolts and spalls
31

except minor breakage at the corner.

32

C.

Repair of unformed surfaces:

33

1.

The Contractor shall test unforme
d surfaces, such as monolithic
34

slabs, for smoothness and to verify surface plane to the tolerances
35

specified for each surface and finish. The Contractor shall correct
36

low and high areas as herein specified.

37

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2.

Test unformed surfaces sloped to drain for truen
ess of slope, in
1

addition to smoothness, using a template having the required slope,
2

Correct high and low areas as herein specified.

3

3.

Repair finished unformed surfaces that contain defects which
4

adversely affect the durability of the concrete. Surface def
ects as
5

such, include cracking, (cracks in excess of 0.01" wide or which
6

penetrate to the reinforcement or completely through non
-
7

reinforced sections regardless of width) spalling, popouts,
8

honeycomb, rock pockets, and other objectionable conditions.

9

4.

Corre
ct high areas in unformed surfaces by grinding, after the
10

concrete has cured sufficiently so that repairs can be made without
11

damage to adjacent areas.

12

5.

Correct low areas in formed surfaces during or immediately after
13

completion of surface finishing operati
ons by cutting out low areas
14

and replacing with fresh concrete. Finish repaired areas to blend
15

into adjacent concrete.

16

6.

Repair defective areas, except random cracks and single holes not
17

exceeding 1 inch diameter, but cutting out and replacing with fresh
18

co
ncrete. Remove defective areas to sound concrete with clean,
19

square cuts, and expose reinforcing steel with at least 3/4"
20

clearance all around. Dampen all concrete surfaces in contact with
21

patching concrete and brush with a neat cement grout coating, or
22

use concrete bonding agent. Place patching concrete before grout
23

takes its initial set. Mix patching concrete of the same materials to
24

provide compact and finish as required to blend with adjacent
25

finished concrete. Cure in the same manner as adjacent c
oncrete.

26

7.

Repair isolated random cracks and single holes not over 1 inch in
27

diameter by the dry
-
pack method. Groove the top of cracks, and
28

cut out holes to sound concrete and clean of dust, dirt and loose
29

particles. Dampen all cleaned concrete surfaces an
d brush with a
30

neat cement grout coating. Place drypack before the cement grout
31

takes its intial set. Mix drypack, consisting of one part Portland
32

cement to 2
-
1/2 parts fine aggregate passing a No. 16 mesh sieve,
33

using only enough water as required for
handling and placing.
34

Compact drypack mixture in place and finish to match adjacent
35

concrete. Keep patch areas continuously moist for not less than 72
36

hours.

37

8.

Repair methods not specified above may be used, subject to the
38

acceptance of the City of Stillwa
ter.

39

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1

E
ND OF
S
ECTION

2