This specification covers design and
supply of all materials, labor and equipment necessary to produce all the cast
in place and precast concrete included in the Contractor's work or as shown on
the drawing or as directed by the Owner.
WORK INCLUDED
Furnishing and testing cement, aggregates, and all other materials for the
production of concrete and grout.
Receiving and handling, storing, and protecting materials for the production of
concrete and grout.
Installation of anchor bolts and embedment in conjunction with concrete work.
Detailing, furnishing, testing and fabricating, reinforcing steel.
Providing concrete mix designs.
Batching, mixing and delivering Portland cement concrete mixtures.
Furnishing, installing and removing forms
Placing reinforcing steel
Furnishing and installing bar supports, spacers, and tie wire
Placing, finishing and curing concrete.
Forming, placing and curing noushriuk grout and dry.
Furnishing and installation of material for all expansion, contraction and
construction joints, including water stops, pre-molded expansion joint filter
and other concrete related materials.
Installation of anchor bolts and embedment in conjunction with concrete work.
Inspection of all work.
CODES AND STANDARDS
The Contractor shall comply with requirements of the requirements of the
applicable codes and standards published by the following organizations :
ASTM American Society for Testing and Materials
ACI American Concrete Instute.
CRSI Concrete Reinforcing Steel Institute, U.S.A.
AASHTO American Association of State Highway and Transportation Officials.
PBI Peraturan Beton Bertulang Indonesia.
SII Standard Industri Indonesia.
USBR United States Bureau of Reclamation
When references are made in this specification to the provisions of specific
codes or standards the Contractor shall strictly comply with those provisions,
unless deviations or substitutions are specifically requested and approved by
the Owner in writing.
QUALITY ASSURANCE/QUALITY CONTROL (QA/QC
Contractor shall fully comply with the Project Quality Assurance/Quality
Control Requirements. For submitting Quality Assurance/Quality Control
Procedures and Documentation the provision of Clause “Submittals” of this
specification shall apply.
SUBMITTALS
PRELIMINARY REVIEW
The source and quality of concrete materials and the concrete proportions
proposed for the work shall be submitted to the Owner for review and approval
before the concrete works is started. Complete certified reports prepared by an
independent testing laboratory and covering the materials and proportions shall
be submitted to the Owner.
REPORTS
Mill Test Reports of Reinforcing Bars : These reports from manufactures shall
accompany each delivery of reinforcing bars, indicating that these bars have
been tested in accordance with ASTM A615. At the same time, two copies of these
reports shall be submitted to the Owner for information purpose.
Reports from the cement manufactures shall accompany each delivery of cement
and shall include the type, brand, manufacturer, composition and method of
handling (scale or bulk) and compliance with ASTM C 150 and all other
requirements of this specification.
Reports on fine aggregates shall include the source, type, gradation,
deleterious substances, soundness and the results of all tests required to
verify compliance with the specified standards.
Reports on coarse aggregates shall include the source, type, gradation,
deleterious substances, soundness, abrasion loss and the results of all tests
required to verify compliance with the standards specified.
Reports on admixtures shall include the ASTM C 494 classification, brand,
manufacturer, and character of the material and lot number. All admixtures
shall be the products of one manufacturer.
When required by the Owner, the Contractor shall at his expense have the water
tested in accordance with ASTM C 94.
STORAGE OF MATERIALS
At all times cement shall be stored in a manner approved by the Owner. The
cement storage area for bagged cement shall be a weather proof building, well
ventilated, lighted and free from dampness. The size of storage shall be sufficient
for 2 weeks continuous output of the batching plant at its designated capacity.
Any bag, package or container that has been damaged or any consignment of
cement that shows sign of deleterious shall be rejected naturally and
Contractor shall remove all rejected cement from the Site without delay.
Concrete bathing operations shall be organized so that cement that has been
longest on site issued first.
Aggregate shall be stored so that they kept clean and free from contamination
and in manner that will protective deterioration or inclusion of foreign
material and contact with sea water. Aggregates of different sizes shall be
stored in separate piles in a manner to avoid segregation. If segregation does
occur, the aggregates shall be removed to conform to specified grading
requirement.
Where a clean hard surface is not available for the stockpiles the bottom 150 m
of the aggregate piles which are in contact with the ground shall not be used.
Reinforcement shall be stored in a manner that will avoid excessive rusting,
coating with grease, oil, dirt and/or other objectionable materials. All
reinforcement shall be stored on site timber or concrete supports suitably
spaced and of sufficient height to keep the steel clear of the ground.
Admixture shall be stored on such a manner as to avoid contamination,
evaporation or damage.
Materials used for Concrete Work shall generally be the product of local
manufacturing plants.
All material used in the Work shall be new and of the best quality of their
respective kinds from approved sources and shall comply with the requirements
of the latest edition of the approved standards or codes of Practice.
The Contractor shall be deemed to have satisfied himself that suitable
materials for concrete and mortar can be obtained in sufficient quantities to
carry out the works.
As soon as possible after the contract has been placed the contractor shall
submit a list giving details of the sources from which he proposes to obtain
concrete and mortar materials. Only materials from approved sources shall be
brought to site. Approval of sources shall no imply acceptance of material
found not conform to this Specification
Materials shall conform to the requirements specified in Table 4.4.2.5 - 1 or
approved equal.
Material for Concrete Work
ITEM
NO
|
MATERIAL
|
ASTM
STANDARDS
|
RESTRICTIONS
OR EXCEPTIONS
|
1.
2.
3.
4.
|
Cement
Fine Aggregate
Coarse Aggregate
Reinforcing Bars (Deformed Bars)
|
C150
C33, C289, C295
C33, C289, C295
4.1 A615 Grade 60
4.2 A615
Grade 40
|
Type II only for foundations structures below grade and
marine Structures.
Type I for above grade Work. Subject to results of
additional ground investigation.
Use only graded natural sand unless otherwise indicated.
Use only graded crushed stone unless otherwise indicated,
with size an specified in Section 7.
For all reinforcing unless other wise indicated.
Reinforcing bars conforming to ASTM A615 with a yield
strength of 40N/mm² are also acceptable
For dowels of equipment foundation over grade slab only
where specifically indicated.
|
Material for Concrete Work (Continued)
ITEM
NO
|
MATERIAL
|
ASTM
STANDARDS
|
RESTRICTIONS
OR EXCEPTIONS
|
5.
6.
7.
8.
|
Bar supports
Form Ties
Welded Steel
Wire Fabric
Air Entraining Admixtures
|
A 185
C 260
|
CRSI Manual of Standard Practice Class C. For mat
foundations on soil or mud mats, use precast concrete blocks having the same
compressive strength as the mat foundation
6.1 Steel ties with PVC sleeves for structure
contact with sea water.
6.2 For all other structural, steel snapties
architectural type with out washers, or better.
Spacing and gauge of wires as indicated on approved
drawings.
|
9.
10.
11.
12.
12.1
12.2
|
Water Reducing Admixture
Membrane Curing Compound
Water
Forms
Plywood (Exposed Surface)
Lumber
|
C 494
C 309
C 94
|
10.1 Type 1, for concrete floor and tread
finished, Type 1-D with fugitive dye for all other work, (wax base not
permitted)
Shall be fresh, clean and drink-able
Waterproof, resin bonded, exterior type
Straight, uniform width and thickness, and free of knots
offsets, holes, and other surface defects.
|
Material for Concrete Work (Continued)
ITEM
NO.
|
MATERIAL
|
ASTM
STANDARDS
|
RESTRICTIONS
OR EXCEPTIONS
|
12.3
12.4
13.
13.1
13.2
13.3
13.4
13.5
14.
|
Chamber strip (Beveled corner)
Metal Deck
Expansion joint material
Filler
Urethene sealant
Primer
Epoxy Bonding
Membrane Curing Compound hardness and floor sealer
Fly Ash
|
ASTM D1752
Fed spec TT-
S-00227E-70
Recommended by manufacture
ASTM C 881
ASTM C 309
ASTM C 618 - 619 Class C or F
|
Wood, surface against concrete planed.
Type I (Sponge rubber) or closed cell plastic foam.
Type I, Class A, greycolour
Type component moisture intensitas epoxy adhesive
Styrene-acrtlate or styrene butadiene min. 18 % percent
solid, nou yellowing moisture loss 0.0399/kg/ cm2 max. meeting water
retention requirement.
Class C fly ash shal
not be used with cement type II.
|
CEMENT
The cement used throughout the works shall be in accordance with ASTM C150 or equal.
All cement shall be delivered to the site under cover in strong, sealed waterproof bags in such quantities and at times suitable for the amount of work in hand. All cement shall be effectively protected against deterioration during storage on the site. Only sufficient cement shall be stored at site to ensure continuity of the works, and to allow testing of any consignment before it is required for use.
Cement manufacturer's test certificates shall be made available to the Owner on request.
ADDITIVES GENERALLY
The cement used throughout the works shall be in accordance with ASTM C150 or equal.
All cement shall be delivered to the site under cover in strong, sealed waterproof bags in such quantities and at times suitable for the amount of work in hand. All cement shall be effectively protected against deterioration during storage on the site. Only sufficient cement shall be stored at site to ensure continuity of the works, and to allow testing of any consignment before it is required for use.
Cement manufacturer's test certificates shall be made available to the Owner on request.
ADDITIVES GENERALLY
Air entraining, water reducing, set accelerating, set
retarding, or other additives shall not be used except with the written
approval of the Owner, following comparative concrete durability and
compression strength tests carried out on concrete made with and without
additives. Any request for approval of use of additives shall be accompanied by
comprehensive documentation setting out the particular benefits and effects of
the product on the concrete mix that is intended to be used. The additives
shall be used strictly in accordance with the manufacturer's instruction and to
the Owner's directions.
Test with additives shall give durability and compressive
strength at least equal to those without additives except that water reducing
agents shall increase the compressive strength by ten (10) percent.
AGGREGATES
Coarse
Aggregates
Coarse aggregates shall be crushed stone with well graded
and show general compliance with the requirements of the appropriate standards.
It shall be clean, hard, strong, fine grained, non friable, non porous and
durable stone of approved quality and shall be obtained from an approved
source. It shall be roughly cubical in shape and be free from dust.
The granulometric curve of the coarse aggregate shall be within the following tolerances, which shall be achieved by means of sifting and screening of the material.
The granulometric curve of the coarse aggregate shall be within the following tolerances, which shall be achieved by means of sifting and screening of the material.
Should the loss by weight, when the aggregates is subjected
to abrasion test by used of the Los Angeles Machine (ASTM 31) exceed 10 % at
100 revolutions or 40 % at 500 revolution, the coarse aggregate shall be
rejected.
Coarse
Aggregate
Screen Size
|
% Age Weight
|
Passing Nominal
|
Maximum Size
|
40 mm
|
20 mm
|
10 mm
|
|
37.5 mm
19.0 mm
9.5 mm
4.75 mm
|
95 - 100
30 - 70
10 – 25
0 – 5
|
100
95 - 100
25 - 55
0 - 10
|
100
85 - 100
0 - 20
|
Size
of Coarse Aggregates
ITEM
NO.
|
PORTION
OF THE WORK
|
GRADING REQUIREMENTS-ASTM C 35
|
|
Nominal Size
(Sieves)
|
Size Number
|
||
1.
2.
|
All concrete 300 mm or less in thickness, unless otherwise
indicated
All other concrete work, unless otherwise indicated
|
19 mm to no. 4
38 mm to no. 4
|
67
467
|
Fine
Aggregate (Sand)
The fine aggregate for concrete and mortar shall comply with
ASTM C 33. The fine aggregate for concrete shall be clean, sharp, fresh-water
or pit sand, or other suitable and approved material, and shall be free from
all impurities.
They clay, silt and fine dust in, or adhering to, the
aggregates shall not exceed five (5) percent by volume. The fine aggregate
shall be well graded within the limits of four and three-quarters (4.75) mm to
six hundred (600) micrometres in size.
The fine aggregates for mortar shall, unless otherwise
specified, be rounded sand or other suitable and approved material and shall be
free from all impurities. The clay, silt or fine dust shall not exceed five (5)
percent by volume. The sand shall consist of particles between two point three
six (2.36) mm and six hundred (600) micrometers in size.
WATER
Water used for mixing concrete and mortar shall be clean, fresh water obtained from an approved source and free from harmful chemicals, oils, organic matter and all other impurities, conforming with the requirements of the ASTM C 94.
Water used for mixing concrete and mortar shall be clean, fresh water obtained from an approved source and free from harmful chemicals, oils, organic matter and all other impurities, conforming with the requirements of the ASTM C 94.
STEEL BAR
REINFORCEMENT
The reinforcement shall comply with the requirement of ASTM
A 615.
The bars shall be round and free from corrosion, cracks,
surface flaws, laminations, rough, jagged and shall not exceed two and one half
(2.5) percent. All bars shall be clean, new and of the diameters described on
the drawings, and shall be transported and stored on site so that they remain
straight, clean, undamaged and free from corrosion, rust or scale.
Bars or different diameters shall be separately bundled and
bars from different sources shall be separately stored, free from direct
contact with wet ground.
Deformed bar shall be used for diameter more than 13 mm and
other sized plained bar may be used.
THREADED INSERTS
THREADED INSERTS
Threaded insert for casting into concrete shall be of the
diameters and dimension shown on the drawings and shall be electro-galvanized
and of malleable iron or mild steel.
LIME PUTTY
Lime putty used for mortar shall be well slaked and kept in
the lime pool for a minimum of four days. It shall be prevented from drying
while in the lime pool.
ADMIXTURE
The use of admixture shall be approved by the Owner.
The use of admixture shall be approved by the Owner.
Any request for approval of use admixtures shall be
accompanied by comprehensive documentation setting out the particular benefits
and effects of the product on the concrete mix that is intended to be used.
The admixture shall be used strictly in accordance with the
manufacturer's instructions and to the Owner's directions.
Admixtures containing calcium chloride in any form shall not
be used. All admixtures shall be product of one manufacturer and shall be
compatible with all other admixtures used.
Waterproof concrete and mortar shall be used where shown on
the drawing. Waterproof shall be by the use of a reliable and approved brand of
admixture. The admixture shall be used strictly in accordance with the
manufacturer's instructions.
STRENGTH, LIMITING, PROPORTIONING AND MIXING REQUIREMENTS
GRADES OF CONCRETE
Applicable grades are shown on the design drawings.
The concrete shall have the minimum compressive strengths
shown below :
CLASS
|
MINIMUM
COMPRESSIVE STRENGTH (Kg/cm2)
|
A
B
C
D
– 1
D
– 2
E
F
|
500
350
270
210
210
180
150
|
This value above shall be tested by a cylindrical
compressive strength method.
Unless otherwise specified, concrete of the various classes
shall be used as follows:
Class A : For prestress concrete spun piles and concrete
sheet piles
Class B : For coal silo and ash silo
Class C : For chimney windshield and T/G pedestal
Class D – 1 : For all concrete work in the buildings and
structures of the power plant, unless otherwise specified.
Class D – 2 : For all concrete work in contact with water
and jetty.
Class E : For slabs on grade, unless otherwise specified
Class F : For lean concrete as specified and for all
concrete not reinforced, unless otherwise specified.
LIMITING REQUIREMENTS
LIMITING REQUIREMENTS
General
The acceptability of concrete shall be decided on the basis of compliance with all of the specified requirements and not on the basis of strength alone.
The acceptability of concrete shall be decided on the basis of compliance with all of the specified requirements and not on the basis of strength alone.
Minimum Cement Factors
Minimum quantity of Portland Cement, expressed in kg per
cubic meter, shall be not less than that indicated in the following table.
NO.
|
CONCRETE
CLASS
|
MINIMUM CEMENT
CONTENT IN Kg/M3
|
MAXIMUM
WATER CEMENT RATIO
|
|
NOMINAL MAXIMUM
OF AGGREGATE
|
||||
20 mm
|
40 mm
|
|||
1.
2.
3.
4.
|
E
D
C
B
|
200
270
300
350
|
180
240
270
320
|
0.52
(Notes 1 & 2)
0.50
(Notes 1 & 2)
|
Note :
1. The water/cement ratio shall not exceed 0.40 by weight for concrete used in marine structures.
2. The water/cement ratio shall not exceed 0.45 for mass concrete without reinforcing exposed to seawater.
3. A sack of cement in Indonesia is 40 kg.
Chlorides
The amount of the total water soluble chloride ion content of any mix shall not exceed the following:
Reinforced concrete : 0.15 % by weight of cement
Mass concrete with -
out reinforcing : 1.00 % by weight of cement
Prestressed concrete : 0.06 % by weight of cement
Sulfates
If sulfates in the aggregate are detected, the aggregate shall be washed to eliminate the water soluble sulfate content.
The total sulfate content of any mix excluding that present in the cement but including any present in other ingredients shall not exceed 0.5 by weight of cement in the mix.
Water
Water for each batch of concrete shall be accurately gauged by measurement of volume in calibrated tank or by weighing. One litre of water shall be equivalent to one kilogram weight.
If the fine and coarse aggregates contain water, adjustment shall be made to the quantity water to be added to the mix by carrying out moisture content test on the aggregate and by slump test on the freshly mixed concrete.
The water used to mix the concrete shall be fresh and clean and drinkable. The water chemistry shall be in accordance with the following :
Total solids per AASHTO T.26
Chlorides per ASTM D512
Sulfates less than 500 mg/litre
Compressive strength of 50 mm cubes made with water must be within 10 % of the strength of 50 mm cubes made using distilled water.
Fine and Coarse Aggregate
The quantities of the coarse aggregate should preferably be determined by weight but where approval has been obtained from the Owner, may be determined by volume.
The conversion of "weight" to "volume" or vice versa shall be based on the weight per cubic metre of the preliminary tests on aggregates. Where batching by volume is approved, suitable batch boxes for measurement of the aggregate shall be made and use.
Allowance shall be made in gauging fine aggregate for increase in volume due to bulking because of moisture content.
Fine and coarse aggregate shall comply with ASTM C 33 and the following:
Water absorption to ASTM C127 to be less than 2 %
The severe weathering regions in Table 3 of ASTM C33.
Magnesium sulfate soundness loss to ASTM C88 to be less than 14 % (compared to 15 % and 18 % limit of ASTM C33).
1. The water/cement ratio shall not exceed 0.40 by weight for concrete used in marine structures.
2. The water/cement ratio shall not exceed 0.45 for mass concrete without reinforcing exposed to seawater.
3. A sack of cement in Indonesia is 40 kg.
Chlorides
The amount of the total water soluble chloride ion content of any mix shall not exceed the following:
Reinforced concrete : 0.15 % by weight of cement
Mass concrete with -
out reinforcing : 1.00 % by weight of cement
Prestressed concrete : 0.06 % by weight of cement
Sulfates
If sulfates in the aggregate are detected, the aggregate shall be washed to eliminate the water soluble sulfate content.
The total sulfate content of any mix excluding that present in the cement but including any present in other ingredients shall not exceed 0.5 by weight of cement in the mix.
Water
Water for each batch of concrete shall be accurately gauged by measurement of volume in calibrated tank or by weighing. One litre of water shall be equivalent to one kilogram weight.
If the fine and coarse aggregates contain water, adjustment shall be made to the quantity water to be added to the mix by carrying out moisture content test on the aggregate and by slump test on the freshly mixed concrete.
The water used to mix the concrete shall be fresh and clean and drinkable. The water chemistry shall be in accordance with the following :
Total solids per AASHTO T.26
Chlorides per ASTM D512
Sulfates less than 500 mg/litre
Compressive strength of 50 mm cubes made with water must be within 10 % of the strength of 50 mm cubes made using distilled water.
Fine and Coarse Aggregate
The quantities of the coarse aggregate should preferably be determined by weight but where approval has been obtained from the Owner, may be determined by volume.
The conversion of "weight" to "volume" or vice versa shall be based on the weight per cubic metre of the preliminary tests on aggregates. Where batching by volume is approved, suitable batch boxes for measurement of the aggregate shall be made and use.
Allowance shall be made in gauging fine aggregate for increase in volume due to bulking because of moisture content.
Fine and coarse aggregate shall comply with ASTM C 33 and the following:
Water absorption to ASTM C127 to be less than 2 %
The severe weathering regions in Table 3 of ASTM C33.
Magnesium sulfate soundness loss to ASTM C88 to be less than 14 % (compared to 15 % and 18 % limit of ASTM C33).
The apparent specific gravity of aggregate as
determined by an approved test, such as in ASTM C127, shall not be less than
2.5.
The potential alkali reactivity of the aggregates and the concrete mixes shal be determined by tests in accordance with the requirements of ASTM C227, C289 and C295.
Elongation index to B.S 812 to be less than 30 %.
Flakiness index to B.S 812 to be less than 25 %.
PROPORTIONS AND SLUMP
The proportions of cement to aggregate shall be the least which will produce a plastic mix of suitable workability for each portion of the works so as to result in uniformly dense concrete free from aggregate pockets or honeycomb.
Slumps shall be not less than 50 mm nor more than 125 mm.
Proportions to meet these requirements shall be established by design mixes in accordance with the Chapter 4 of ACI 318 and all concrete work shall be in strict conformance with the design mixes.
An air-entraining admixture conforming to the requirements of sub section mentioned before, Admixtures, shall be added at the mixer in such quantities as to produce concrete with total air content conforming to the moderate exposure requirements of table 4. 5.1 of ACI 318-83. The admixture shall be added as a solution in a portion of the mixing water, using a suitable mechanically activated dispenser.
CONCRETE DESIGN MIXES
Contractor shall furnish to the testing laboratory with sufficient quantities of cement, aggregates, water and admixtures, from the same sources as will be used for the Work, for testing of these materials and preparations of trial mixtures. Materials thus furnished shall be used for the entire project without changes. Changes in the source of materials will require the preparation of trial mixes and a revised mix design.
Trial mixtures shall be designed to produce a slump of max 125 mm and within 0.5 percent of the maximum allowable air content. For each proposed mixture at least three compressive of cylinders for each age shall be made and cored in accordance with ASTM C192. The cylinders shall be tested for strength in accordance to ASTM C39 at 3, 7 and 28 days. When fly ash or pozolan is used, control tests shall be made also at 90 days from the test results curves shall be plotted showing the water-cement ratio relationship with the strength. Using these curve concrete proportion shall be selected to produce the average strength required by ACI 318.
When the mix proportions of each grade of concrete have been finalized and approved by the Owner, the Contractor shall not vary these proportions without a good and valid reason for doing so and only with the Owner's approval. Any such change of proportions, arising from any cause whatsoever shall not be considered as a basis for a claim to an increase in unit rated for concrete.
The Contractor shall submit the test result of design mixes to the Owner at least six weeks before starting concrete work.
Mix Proportions for Concrete Grades
It shall be the contractors responsibility to design the concrete mixes, using the constitute materials specified, to comply with the requirements of the various grades of concrete.
The contractor shall, as soon as possible after the contract has been placed, obtain representative samples of water and fine and coarse aggregates in sufficient quantities for testing as directed by the Owner. Tests so designated by the Owner shall be in accordance with the provisions of the appropriate standards by the Owner. Materials which do not comply with those specified under Clause 6. shall be rejected.
In determining the mix proportions, the contractor shall use trial mixes in accordance with the recommendation of Codes and Standards specified in Section 2 to establish the most suitable combination that will give concrete of the maximum water/cement ratios consistent with the strength specified for the different concrete grades. Water cement ratios will normally be not greater than 0.55 by weight otherwise specified, approved or instructed for each grade of concrete.
Approval of Mix Proportions
The contractor shall submit to the Owner for approval the proportions of ingredients he proposes to use for each grade of concrete, and the basis on which he has designed the mix.
Under the supervision of the Owner the contractor shall make six (6) test cylinders or cubes of each grade of concrete, using his proposed proportions.
Two (2) cylinders or cubes of each set shall be tested at three (3) days and seven (7) by an independent authority approved by the Owner, the remainder tested at twenty-eight (28) days.
All test cylinders or cubes shall be given a reference number and the contractor shall supply the Owner with a record, in duplicate showing the reference number, date made, concrete grade, proportions of mix, water cement ratio and the concrete slump.
The minimum designed strengths obtained from the trial mix tests shall be one and one third (1 1/3) times the minimum crushing strengths specified in Section 7 for each grade of concrete.
FORMWORK
Formwork shall be constructed from timber, metal, plastic or concrete, lined as necessary for special finished and designed with the quality and strength required to ensure rigidity throughout placing, ramming, vibration and setting of the concrete, without detrimental effect.
GENERAL REQUIREMENTS
Forms shall be designed and constructed to produce hardened concrete having the shape, lines, grade and dimensions required by the approved drawings and conform to the applicable requirements of ACI 301 and ACI 347.
In the design of formwork, consideration shall be given to the following:
§ Rate and method of placing concrete.
§ Weight of concrete.
§ Construction loads including vertical, horizontal, and impact loads.
§ Concrete pressure and form tightness, particularly when high range water reducer concrete is used.
The potential alkali reactivity of the aggregates and the concrete mixes shal be determined by tests in accordance with the requirements of ASTM C227, C289 and C295.
Elongation index to B.S 812 to be less than 30 %.
Flakiness index to B.S 812 to be less than 25 %.
PROPORTIONS AND SLUMP
The proportions of cement to aggregate shall be the least which will produce a plastic mix of suitable workability for each portion of the works so as to result in uniformly dense concrete free from aggregate pockets or honeycomb.
Slumps shall be not less than 50 mm nor more than 125 mm.
Proportions to meet these requirements shall be established by design mixes in accordance with the Chapter 4 of ACI 318 and all concrete work shall be in strict conformance with the design mixes.
An air-entraining admixture conforming to the requirements of sub section mentioned before, Admixtures, shall be added at the mixer in such quantities as to produce concrete with total air content conforming to the moderate exposure requirements of table 4. 5.1 of ACI 318-83. The admixture shall be added as a solution in a portion of the mixing water, using a suitable mechanically activated dispenser.
CONCRETE DESIGN MIXES
Contractor shall furnish to the testing laboratory with sufficient quantities of cement, aggregates, water and admixtures, from the same sources as will be used for the Work, for testing of these materials and preparations of trial mixtures. Materials thus furnished shall be used for the entire project without changes. Changes in the source of materials will require the preparation of trial mixes and a revised mix design.
Trial mixtures shall be designed to produce a slump of max 125 mm and within 0.5 percent of the maximum allowable air content. For each proposed mixture at least three compressive of cylinders for each age shall be made and cored in accordance with ASTM C192. The cylinders shall be tested for strength in accordance to ASTM C39 at 3, 7 and 28 days. When fly ash or pozolan is used, control tests shall be made also at 90 days from the test results curves shall be plotted showing the water-cement ratio relationship with the strength. Using these curve concrete proportion shall be selected to produce the average strength required by ACI 318.
When the mix proportions of each grade of concrete have been finalized and approved by the Owner, the Contractor shall not vary these proportions without a good and valid reason for doing so and only with the Owner's approval. Any such change of proportions, arising from any cause whatsoever shall not be considered as a basis for a claim to an increase in unit rated for concrete.
The Contractor shall submit the test result of design mixes to the Owner at least six weeks before starting concrete work.
Mix Proportions for Concrete Grades
It shall be the contractors responsibility to design the concrete mixes, using the constitute materials specified, to comply with the requirements of the various grades of concrete.
The contractor shall, as soon as possible after the contract has been placed, obtain representative samples of water and fine and coarse aggregates in sufficient quantities for testing as directed by the Owner. Tests so designated by the Owner shall be in accordance with the provisions of the appropriate standards by the Owner. Materials which do not comply with those specified under Clause 6. shall be rejected.
In determining the mix proportions, the contractor shall use trial mixes in accordance with the recommendation of Codes and Standards specified in Section 2 to establish the most suitable combination that will give concrete of the maximum water/cement ratios consistent with the strength specified for the different concrete grades. Water cement ratios will normally be not greater than 0.55 by weight otherwise specified, approved or instructed for each grade of concrete.
Approval of Mix Proportions
The contractor shall submit to the Owner for approval the proportions of ingredients he proposes to use for each grade of concrete, and the basis on which he has designed the mix.
Under the supervision of the Owner the contractor shall make six (6) test cylinders or cubes of each grade of concrete, using his proposed proportions.
Two (2) cylinders or cubes of each set shall be tested at three (3) days and seven (7) by an independent authority approved by the Owner, the remainder tested at twenty-eight (28) days.
All test cylinders or cubes shall be given a reference number and the contractor shall supply the Owner with a record, in duplicate showing the reference number, date made, concrete grade, proportions of mix, water cement ratio and the concrete slump.
The minimum designed strengths obtained from the trial mix tests shall be one and one third (1 1/3) times the minimum crushing strengths specified in Section 7 for each grade of concrete.
FORMWORK
Formwork shall be constructed from timber, metal, plastic or concrete, lined as necessary for special finished and designed with the quality and strength required to ensure rigidity throughout placing, ramming, vibration and setting of the concrete, without detrimental effect.
GENERAL REQUIREMENTS
Forms shall be designed and constructed to produce hardened concrete having the shape, lines, grade and dimensions required by the approved drawings and conform to the applicable requirements of ACI 301 and ACI 347.
In the design of formwork, consideration shall be given to the following:
§ Rate and method of placing concrete.
§ Weight of concrete.
§ Construction loads including vertical, horizontal, and impact loads.
§ Concrete pressure and form tightness, particularly when high range water reducer concrete is used.
Forms shall be readily removable
without damaging the concrete. The form material shall produce the required
surface finish. Defects, such as chipped plywood or kinks in steel forms, shall
not be permitted on exposed surface.
Forms shall be supported by a propriety steel formwork support system approved by the Owner, braced and tied to maintain position, shape, and alignment during and after placing concrete therein. Wales, studs, internal ties, and other form supports shall be of sufficient size and number and shall be located and spaced to that proper working presses therein are not exceeded.
The top edges of forms for walls, equipment bases, and other concrete which is to be finished to a specified elevation, slope, or contour, shall be brought to a true line and grade so that the top concrete surface can be finished with a screed or template resting on the top edges of the forms. Wall forms, on one side at least, shall not extend above horizontal construction joints.
Completed work shall have a smooth finish and uniform colour, and shall be level, plumb and true. Forms shall be substantial and sufficiently tight to prevent leakage of mortar. When forms, for slabs and roofs, in the form of metal decking are used, Contractor shall provide suitable closures to prevent leakage of mortar.
Bolts and rods used for internal ties shall be arranged so that all metal remaining in concrete shall be not less than 75 mm from concrete surface after ties are removed for concrete exposed to sea or river water and 25 mm from concrete surface for all other works unless otherwise indicated on the design drawings.
Temporary openings shall be provided at base of forms for columns, walls, piers, and at other points where necessary to facilitate cleaning and inspection prior to placing of concrete.
All exposed projecting corners of concrete work, such as piers, columns, equipment foundations, etc shall be leveled. Bevel size shall be 25 mm by 25 mm unless otherwise specified.
CLEANING AND TREATMENT OF FORMS
No concrete shall be placed in any portion of the work until the forms for the position have been completed by the Contractor and reviewed by the Owner. All rubbish shall be removed from the interior of forms before concrete is placed.
Forms for exposed concrete surfaces shall be coated with non-staining mineral oil, applied before reinforcement is placed. For unexposed concrete surfaces, forms may be wetted thoroughly with water. Surplus coating shall be removed before concrete placement. Forms that are to be used for forming concrete surfaces on which tile adhesives, paint, epoxies, masonry coatings or overlays are to be applied, shall not be treated with form coating or release agents that leave residuals on the surface of the concrete. The release agent shall be chosen by the Contractor and approved by the Owner. Only one agent shall be used for all surfaces that are permanently exposed.
REMOVAL OF FORMS
Forms shall not be removed until the concrete has acquired sufficient strength to safely carry its own weight and any construction loads that may be imposed on it.
Forms for columns, walls, sides of beams, slabs and girders and other parts not supporting the weight of the concrete shall be removed as soon as practicable to avoid delay in curing and in repairing imperfections.
Methods used for removal of formwork shall be such as to prevent marring, breakage or other damage to concrete. Removal of formwork shall conform to the applicable requirements of ACI 301.
Temporary shoring for suspended elements shall not be disturbed during removal of column forms.
FORMS FOR EXPOSED SURFACES
'Exposed Surfaces’ shall mean all formed concrete surfaces exposed to view on completion of work, unless otherwise indicated.
Forms for all exposed surfaces shall produce extremely smooth, dense and true finishes free of fins, imperfections or other defects. For exposed surfaces of structures in contact with ground, such finish shall extend 300 mm below finish grade.
Forms shall consist of plywood, lined forms or accepted equal. Plywood shall be water-resistant and shall be treated to prevent raising of the grain. Lining shall consist of accepted non-absorptive fiber board plastic coated to resist moisture and with a hard smooth surface on contact side.
CONSTRUCTION DETAILS OPENINGS IN CONCRETE
Openings, pockets, chases, recesses, slots etc. shall be provided in walls, piers, floors or other portions of concrete work for structural steel, conduit, pipe, sewers, sleeves, and similar items, as may be required.
All such openings, pockets, chases etc. shall be filled with concrete after proceeding items are installed as the work progresses. Finishing shall be applied to exposed surfaces of such concrete fills to match adjoining concrete work.
Concrete wall and floor openings for piping and other fixtures which will be installed after the walls and floors are built shall be of sufficient size that adequate space is available for the proper compaction of concrete which will be placed later around the pipe or fixture. The top of each wall opening shall be sloped or beveled to provide adequate space for placing and compacting the pipe embedment concrete. Water stops shall be provided around wall openings below grade and floor opening which are exposed to weather or sub-emergence.
EMBEDDED MATERIALS
Embedded materials include all work which is by Contractor and also all pipe, conduit, ground bars, electrical equipment, etc. placed and secured by others. During placement of concrete protection and care shall be taken so as do not dislodge any of these installations.
CONSTRUCTION JOINTS
All construction joints shall be provided as shown on design drawings and/or as proposed by the Contractor and accepted by the Owner.
Where not indicated on drawings, the Contractor shall locate joints so as satisfy the criteria given the subsection 9.3.4 and not be impair the strength of the structure. Contractor shall submit the locations for the Owner's acceptance prior to placement.
If Contractor wants to revise locations of construction joints or to add or delete construction joints, drawings showing proposed changes shall be submitted for review by the Owner if requested. All changes, including required waterstops if any, shall be made at no cost to Owner.
Space of construction joints in slabs shall be not greater than 15 m in plan. Vertical construction joints in walls shall be arranged so that the horizontal length of placement does not exceed 15 m. Maximum spacing between horizontal construction joints shall not exceed 5 m, unless adequate space is available for working inside of the forms.
Construction joints shall be cleaned by sandblasting, water blasting, or scarifying and roughening until all unsatisfactory concrete, laitance, coatings, stains, debris, and other foreign materials removed. All loose material shall be removed by washing the surface of the concrete thoroughly.
Air-water cutting of horizontal joints may be performed in lieu sandblasting or water blasting. Before placing the next lift, supplement air-water cutting by any of the methods or Subparagraph 9.3.5 where laintance, coating, or stains have not been satisfactorily removed.
When air-water cutting is used, it shall be accomplished between initial and final set. When the surface of a lift is congested with reinforcing steel, and it is relatively in, accessible, or when it is undesirable to disturb the surface, sandblasting, water blasting or scarify and roughening shall provided after the final set.
Horizontal surfaces shall be covered with grout or starter mix immediately before the concrete is placed. Grout with the same sand cement ratio as that used in the concrete mix shall be provided.
EXPANSION JOINTS
Expansion Joints
Expansion joints shall be located and constructed as indicated on the design drawings. Expansion joint filler shall be firmly bonded to the previously poured joints. Face with a suitable adhesive and the new concrete shall be poured directly against the joint filler.
Accessible edges of each expansion joint shall be sealed with the sealer applied in accordance with the manufacturer's directions.
Forms shall be supported by a propriety steel formwork support system approved by the Owner, braced and tied to maintain position, shape, and alignment during and after placing concrete therein. Wales, studs, internal ties, and other form supports shall be of sufficient size and number and shall be located and spaced to that proper working presses therein are not exceeded.
The top edges of forms for walls, equipment bases, and other concrete which is to be finished to a specified elevation, slope, or contour, shall be brought to a true line and grade so that the top concrete surface can be finished with a screed or template resting on the top edges of the forms. Wall forms, on one side at least, shall not extend above horizontal construction joints.
Completed work shall have a smooth finish and uniform colour, and shall be level, plumb and true. Forms shall be substantial and sufficiently tight to prevent leakage of mortar. When forms, for slabs and roofs, in the form of metal decking are used, Contractor shall provide suitable closures to prevent leakage of mortar.
Bolts and rods used for internal ties shall be arranged so that all metal remaining in concrete shall be not less than 75 mm from concrete surface after ties are removed for concrete exposed to sea or river water and 25 mm from concrete surface for all other works unless otherwise indicated on the design drawings.
Temporary openings shall be provided at base of forms for columns, walls, piers, and at other points where necessary to facilitate cleaning and inspection prior to placing of concrete.
All exposed projecting corners of concrete work, such as piers, columns, equipment foundations, etc shall be leveled. Bevel size shall be 25 mm by 25 mm unless otherwise specified.
CLEANING AND TREATMENT OF FORMS
No concrete shall be placed in any portion of the work until the forms for the position have been completed by the Contractor and reviewed by the Owner. All rubbish shall be removed from the interior of forms before concrete is placed.
Forms for exposed concrete surfaces shall be coated with non-staining mineral oil, applied before reinforcement is placed. For unexposed concrete surfaces, forms may be wetted thoroughly with water. Surplus coating shall be removed before concrete placement. Forms that are to be used for forming concrete surfaces on which tile adhesives, paint, epoxies, masonry coatings or overlays are to be applied, shall not be treated with form coating or release agents that leave residuals on the surface of the concrete. The release agent shall be chosen by the Contractor and approved by the Owner. Only one agent shall be used for all surfaces that are permanently exposed.
REMOVAL OF FORMS
Forms shall not be removed until the concrete has acquired sufficient strength to safely carry its own weight and any construction loads that may be imposed on it.
Forms for columns, walls, sides of beams, slabs and girders and other parts not supporting the weight of the concrete shall be removed as soon as practicable to avoid delay in curing and in repairing imperfections.
Methods used for removal of formwork shall be such as to prevent marring, breakage or other damage to concrete. Removal of formwork shall conform to the applicable requirements of ACI 301.
Temporary shoring for suspended elements shall not be disturbed during removal of column forms.
FORMS FOR EXPOSED SURFACES
'Exposed Surfaces’ shall mean all formed concrete surfaces exposed to view on completion of work, unless otherwise indicated.
Forms for all exposed surfaces shall produce extremely smooth, dense and true finishes free of fins, imperfections or other defects. For exposed surfaces of structures in contact with ground, such finish shall extend 300 mm below finish grade.
Forms shall consist of plywood, lined forms or accepted equal. Plywood shall be water-resistant and shall be treated to prevent raising of the grain. Lining shall consist of accepted non-absorptive fiber board plastic coated to resist moisture and with a hard smooth surface on contact side.
CONSTRUCTION DETAILS OPENINGS IN CONCRETE
Openings, pockets, chases, recesses, slots etc. shall be provided in walls, piers, floors or other portions of concrete work for structural steel, conduit, pipe, sewers, sleeves, and similar items, as may be required.
All such openings, pockets, chases etc. shall be filled with concrete after proceeding items are installed as the work progresses. Finishing shall be applied to exposed surfaces of such concrete fills to match adjoining concrete work.
Concrete wall and floor openings for piping and other fixtures which will be installed after the walls and floors are built shall be of sufficient size that adequate space is available for the proper compaction of concrete which will be placed later around the pipe or fixture. The top of each wall opening shall be sloped or beveled to provide adequate space for placing and compacting the pipe embedment concrete. Water stops shall be provided around wall openings below grade and floor opening which are exposed to weather or sub-emergence.
EMBEDDED MATERIALS
Embedded materials include all work which is by Contractor and also all pipe, conduit, ground bars, electrical equipment, etc. placed and secured by others. During placement of concrete protection and care shall be taken so as do not dislodge any of these installations.
CONSTRUCTION JOINTS
All construction joints shall be provided as shown on design drawings and/or as proposed by the Contractor and accepted by the Owner.
Where not indicated on drawings, the Contractor shall locate joints so as satisfy the criteria given the subsection 9.3.4 and not be impair the strength of the structure. Contractor shall submit the locations for the Owner's acceptance prior to placement.
If Contractor wants to revise locations of construction joints or to add or delete construction joints, drawings showing proposed changes shall be submitted for review by the Owner if requested. All changes, including required waterstops if any, shall be made at no cost to Owner.
Space of construction joints in slabs shall be not greater than 15 m in plan. Vertical construction joints in walls shall be arranged so that the horizontal length of placement does not exceed 15 m. Maximum spacing between horizontal construction joints shall not exceed 5 m, unless adequate space is available for working inside of the forms.
Construction joints shall be cleaned by sandblasting, water blasting, or scarifying and roughening until all unsatisfactory concrete, laitance, coatings, stains, debris, and other foreign materials removed. All loose material shall be removed by washing the surface of the concrete thoroughly.
Air-water cutting of horizontal joints may be performed in lieu sandblasting or water blasting. Before placing the next lift, supplement air-water cutting by any of the methods or Subparagraph 9.3.5 where laintance, coating, or stains have not been satisfactorily removed.
When air-water cutting is used, it shall be accomplished between initial and final set. When the surface of a lift is congested with reinforcing steel, and it is relatively in, accessible, or when it is undesirable to disturb the surface, sandblasting, water blasting or scarify and roughening shall provided after the final set.
Horizontal surfaces shall be covered with grout or starter mix immediately before the concrete is placed. Grout with the same sand cement ratio as that used in the concrete mix shall be provided.
EXPANSION JOINTS
Expansion Joints
Expansion joints shall be located and constructed as indicated on the design drawings. Expansion joint filler shall be firmly bonded to the previously poured joints. Face with a suitable adhesive and the new concrete shall be poured directly against the joint filler.
Accessible edges of each expansion joint shall be sealed with the sealer applied in accordance with the manufacturer's directions.
Expansion joint so designated on the
design drawings, and which will be subjected to differential hydrostatic
pressure, shall be provided with a flexible waterstop. Waterstop embedment
shall be equal on each side of the joint.
Flexible waterstops shall be spliced in strict conformity with the recommendations of the waterstop manufacturer.
CONNECTIONS TO EXISTING CONCRETE
Connections of new concrete to existing concrete shall include all necessary cutting, patching and fitting required for a neat and workmanlike job. All exposed surfaces shall be cut true and smooth and shall be patched and finished to match adjoining concrete surfaces.
Flexible waterstops shall be spliced in strict conformity with the recommendations of the waterstop manufacturer.
CONNECTIONS TO EXISTING CONCRETE
Connections of new concrete to existing concrete shall include all necessary cutting, patching and fitting required for a neat and workmanlike job. All exposed surfaces shall be cut true and smooth and shall be patched and finished to match adjoining concrete surfaces.
WATERSTOP
General
Flexible waterstops shall be used for all construction joints in concrete below grade level and as shown on design drawing. The waterstops shall be suitable for the hydrostatic pressure.
Material
The rubber waterstops shall be made from a high grade compound conforming to the requirements of CRD-C572. Contractor shall provide standard factory fabricated tees, ells, crosses and other joint fittings required for all intersections.
Unless shown otherwise on the design drawings the rubber waterstops shall be 230 mm by 10 mm with "0" bulb closed center section.
Fabrication
The rubber waterstop may be molded or extruded. All materials shall be molded or extruded and cured in such a manner that any cross section will be dense, homogeneous and free from porosity and other imperfections.
Tests and Test Reports
Rubber waterstops shall be subject to laboratory tests prior to shipment to the Project Site. Testing of rubber waterstops shall conform to the requirements of CDRC572. The rubber waterstop shall be capable of withstanding a maximum design hydrostatic head of 20 meters. Manufacturer shall furnish certified copies of all laboratory test reports.
General
Flexible waterstops shall be used for all construction joints in concrete below grade level and as shown on design drawing. The waterstops shall be suitable for the hydrostatic pressure.
Material
The rubber waterstops shall be made from a high grade compound conforming to the requirements of CRD-C572. Contractor shall provide standard factory fabricated tees, ells, crosses and other joint fittings required for all intersections.
Unless shown otherwise on the design drawings the rubber waterstops shall be 230 mm by 10 mm with "0" bulb closed center section.
Fabrication
The rubber waterstop may be molded or extruded. All materials shall be molded or extruded and cured in such a manner that any cross section will be dense, homogeneous and free from porosity and other imperfections.
Tests and Test Reports
Rubber waterstops shall be subject to laboratory tests prior to shipment to the Project Site. Testing of rubber waterstops shall conform to the requirements of CDRC572. The rubber waterstop shall be capable of withstanding a maximum design hydrostatic head of 20 meters. Manufacturer shall furnish certified copies of all laboratory test reports.
Installation
The waterstop shall be installed with approximately one-half of its width embedded in the concrete on each side of the joint. Nailing of waterstop to formwork is not permitted. Care shall be exercised in placing and vibrating the concrete about the waterstop, to insure complete filling of the concrete around the waterstop, and to obtain a continuous bond between the concrete and the waterstop at all points around the periphery of the waterstop. Waterstops shall be cut and spliced at changes in direction as necessary to avoid buckling or distorting of the web or flange. Ensure all joints shall develop water tightness equal to that of the continuous waterstop material. Rubber unions and rubber cement shall be used for splicing waterstops at all joints and at fittings.
The Contractor shall take suitable precautions to support and protect the waterstops during the progress of the work and shall repair or replace any damaged waterstops as directed by the Owner. All waterstops shall be protected from oil or grease.
In the event the waterstop is installed in the concrete on one side of a joint more than one month prior to the scheduled date of placing concrete on the other side of the joint, the exposed waterstop shall be covered or shaded to protect it from the direct rays of the sun during exposure.
Manufacturer's Representative
The Contractor shall provide the services, at no additional cost to Owner, of a technically qualified manufacturer's field representive to instruct Contractor's field installation personnel on the proper procedures for the installation of the waterstops.
PREMOLDED EXPANSION JOINT FILLER
Premolded expansion joint filler shall conform to ASTM D 1752. Type III self-expanding cork. Thickness, widths, and lengths shall be as shown on drawings.
MATERIALS INCLUDED
Reinforcement shall include all reinforcing bars, stirrups, spirals, and other reinforcement materials with all necessary wire ties, bar supports, spacers, block supports and other devices required to install and secure reinforcement properly.
The waterstop shall be installed with approximately one-half of its width embedded in the concrete on each side of the joint. Nailing of waterstop to formwork is not permitted. Care shall be exercised in placing and vibrating the concrete about the waterstop, to insure complete filling of the concrete around the waterstop, and to obtain a continuous bond between the concrete and the waterstop at all points around the periphery of the waterstop. Waterstops shall be cut and spliced at changes in direction as necessary to avoid buckling or distorting of the web or flange. Ensure all joints shall develop water tightness equal to that of the continuous waterstop material. Rubber unions and rubber cement shall be used for splicing waterstops at all joints and at fittings.
The Contractor shall take suitable precautions to support and protect the waterstops during the progress of the work and shall repair or replace any damaged waterstops as directed by the Owner. All waterstops shall be protected from oil or grease.
In the event the waterstop is installed in the concrete on one side of a joint more than one month prior to the scheduled date of placing concrete on the other side of the joint, the exposed waterstop shall be covered or shaded to protect it from the direct rays of the sun during exposure.
Manufacturer's Representative
The Contractor shall provide the services, at no additional cost to Owner, of a technically qualified manufacturer's field representive to instruct Contractor's field installation personnel on the proper procedures for the installation of the waterstops.
PREMOLDED EXPANSION JOINT FILLER
Premolded expansion joint filler shall conform to ASTM D 1752. Type III self-expanding cork. Thickness, widths, and lengths shall be as shown on drawings.
MATERIALS INCLUDED
Reinforcement shall include all reinforcing bars, stirrups, spirals, and other reinforcement materials with all necessary wire ties, bar supports, spacers, block supports and other devices required to install and secure reinforcement properly.
DETAILING
When placing drawings, bending details and bills of materials are not part of the contract design drawings, the Contractor shall submit placing drawings and accompanying bending details to the Owner prior to fabrication. The placing drawings shall reference the design drawings. Bar lists or bills of material shall reference the related placing drawings.
FABRICATION
The details of fabrication shall conform to ACI 315 and 318. In case of conflict, ACI 318 shall govern.
Cutting, bending and tolerances shall be in accordance with CRSI Manual of Standard Practice Reinforcement may be supplied pre-bent from a manufacturer or in stock lengths and cold bent on site. Bending of reinforcing bars in hardened concrete will not be permitted.
Heating, welding and tack welding of reinforcement as part of the fabrication process, is expressly prohibited.
SPLICING OF REINFORCING BARS
Splicing shall conform to the applicable requirements of ACI 318. Mechanical splices shall be approved by the Owner and shall be in accordance with manufacturer's recommendations.
Splices shall be located in accordance with the design drawings. Splices shall not be used in regions of maximum bending stress. Welded splices shall not be used.
CONCRETE COVER
Thickness of concrete cover shall be in accordance with the applicable requirements of ACI 318 and CRSI Manual of Standard Practice, unless otherwise indicated. Concrete cover shall be clearly indicated on the approved drawings.
Except as otherwise indicated on the drawings, the reinforcement of concrete deposited against the ground shall have not less than 85 mm of concrete between the concrete surface and the ground surface. For concrete below grade level but consolidated between forms the minimum cover shall be 75 mm. When concrete surfaces are to be exposed to the weather, the reinforcement shall be protected with not less than 50 mm of concrete for bars larger than 16 mm diameter and not less than 40 mm for bars with 16 mm diameter or smaller.
The concrete protective covering for any reinforcement of surfaces not exposed directly to the ground or weather shall be not less than 25 mm nor the bar diameter.
PLACEMENT
All reinforcement shall be free of loose rust or scale, grease, dirt or any other coating that would reduce or destroy the bond. Reinforcement shall be accurately positioned on supports, spacers, hangers, concrete blocks or other reinforcements, and shall be secured in place during course of construction.
With the exception of lapped portions of spliced bars which are wired of clamped together, the clear distance between parallel bars shall be not less than 1.5 times the maximum size of coarse aggregate in the concrete, or less than 25 mm in beams, 40 mm in columns, or 50 mm in other locations.
Where reinforcement in beams in placed in two or more layers, the bars in the upper layer shall be placed directly above the bars in the lower layer and the clear distance between bars shall be not less than 25 mm.
Bar supports may be used provided they are clamped or wired to the reinforcement.
FIELD BENDING
If necessary and approved by the Owner, reinforcing bars projected from existing concrete may be bent, provided that the bending and the subsequent straightening are performed as specified herein.
The minimum distance from existing concrete surface to the beginning of bend and the minimum inside diameter of bend shall be :
Bar diameter 8 - 16 mm, 6 bar diameter
Bar diameter 16 - 36 mm, 8 bar diameter
Bar diameter over 36 mm, 10 bar diameter
Bar up to 16 mm inclusive may be cold bent once. Preheating is required for subsequent bending and straightening, as specified below.
Preheating is required for bars over 16 mm diameter in all cases. Heat for bending or straightening bars shall be applied as uniformly as possible over a length of bar equal to approximately 10 bar diameters. The heated length shall be centered at the middle of the arc of the completed bend. The bar temperature shall be between 580 and 64 °C, and maintained at that level until bending or straightening is completed. The temperature of the bar at the concrete interface shall not exceed 25 °C. Temperature-measuring crayons or a contact pyrometer shall be used determine the temperature. Care shall be taken to prevent quenching bars, either by application of water or by exposure to rain.
Straightened bars shall be inspected to determine whether they are cracked or otherwise damaged. Any damaged portions shall be removed and replaced as required by the owner.
All costs in connection with any such heating, bending, or straightening one for the convenience of the Contractor and all costs in connection with any repair or replacement required by reason of such heating, bending, or straightening shall be borne by the Contractor.
PLACING OF WELDED WIRE FABRIC
Carefully place fabric reinforcement and maintain in the position before and during placing of concrete.
ANCHORING DOWELS
All dowels shall be securely anchored in place by wire tying, etc, before starting placement of concrete.
COATING DOWELS FOR FUTURE EXTENSION
Exposed reinforcing bars and metal waterstops intended for bending with future work shall be protected from corrosion with two coats of "Bitumastic" coating. Before coating the dowels, two coats of Bitumastic Concrete Penetrant shall be applied on the surface adjacent to the dowels. When the dowels are coated, the coated concrete surface shall be included as an integral part of the dowel coating.
COMPLIANCE WITH STRENGTH REQUIREMENTS
COMPRESSIVE STRENGTH
Compliance with the specified compressive strength shall be measured by tests made on cylinders at an age of 28 days if fly ash or pozzolan is used for replacing part of the cement 90 days test cylinders shall be used.
STRENGTH TEST RESULTS
Strength test results shall conform to the following requirements.
When placing drawings, bending details and bills of materials are not part of the contract design drawings, the Contractor shall submit placing drawings and accompanying bending details to the Owner prior to fabrication. The placing drawings shall reference the design drawings. Bar lists or bills of material shall reference the related placing drawings.
FABRICATION
The details of fabrication shall conform to ACI 315 and 318. In case of conflict, ACI 318 shall govern.
Cutting, bending and tolerances shall be in accordance with CRSI Manual of Standard Practice Reinforcement may be supplied pre-bent from a manufacturer or in stock lengths and cold bent on site. Bending of reinforcing bars in hardened concrete will not be permitted.
Heating, welding and tack welding of reinforcement as part of the fabrication process, is expressly prohibited.
SPLICING OF REINFORCING BARS
Splicing shall conform to the applicable requirements of ACI 318. Mechanical splices shall be approved by the Owner and shall be in accordance with manufacturer's recommendations.
Splices shall be located in accordance with the design drawings. Splices shall not be used in regions of maximum bending stress. Welded splices shall not be used.
CONCRETE COVER
Thickness of concrete cover shall be in accordance with the applicable requirements of ACI 318 and CRSI Manual of Standard Practice, unless otherwise indicated. Concrete cover shall be clearly indicated on the approved drawings.
Except as otherwise indicated on the drawings, the reinforcement of concrete deposited against the ground shall have not less than 85 mm of concrete between the concrete surface and the ground surface. For concrete below grade level but consolidated between forms the minimum cover shall be 75 mm. When concrete surfaces are to be exposed to the weather, the reinforcement shall be protected with not less than 50 mm of concrete for bars larger than 16 mm diameter and not less than 40 mm for bars with 16 mm diameter or smaller.
The concrete protective covering for any reinforcement of surfaces not exposed directly to the ground or weather shall be not less than 25 mm nor the bar diameter.
PLACEMENT
All reinforcement shall be free of loose rust or scale, grease, dirt or any other coating that would reduce or destroy the bond. Reinforcement shall be accurately positioned on supports, spacers, hangers, concrete blocks or other reinforcements, and shall be secured in place during course of construction.
With the exception of lapped portions of spliced bars which are wired of clamped together, the clear distance between parallel bars shall be not less than 1.5 times the maximum size of coarse aggregate in the concrete, or less than 25 mm in beams, 40 mm in columns, or 50 mm in other locations.
Where reinforcement in beams in placed in two or more layers, the bars in the upper layer shall be placed directly above the bars in the lower layer and the clear distance between bars shall be not less than 25 mm.
Bar supports may be used provided they are clamped or wired to the reinforcement.
FIELD BENDING
If necessary and approved by the Owner, reinforcing bars projected from existing concrete may be bent, provided that the bending and the subsequent straightening are performed as specified herein.
The minimum distance from existing concrete surface to the beginning of bend and the minimum inside diameter of bend shall be :
Bar diameter 8 - 16 mm, 6 bar diameter
Bar diameter 16 - 36 mm, 8 bar diameter
Bar diameter over 36 mm, 10 bar diameter
Bar up to 16 mm inclusive may be cold bent once. Preheating is required for subsequent bending and straightening, as specified below.
Preheating is required for bars over 16 mm diameter in all cases. Heat for bending or straightening bars shall be applied as uniformly as possible over a length of bar equal to approximately 10 bar diameters. The heated length shall be centered at the middle of the arc of the completed bend. The bar temperature shall be between 580 and 64 °C, and maintained at that level until bending or straightening is completed. The temperature of the bar at the concrete interface shall not exceed 25 °C. Temperature-measuring crayons or a contact pyrometer shall be used determine the temperature. Care shall be taken to prevent quenching bars, either by application of water or by exposure to rain.
Straightened bars shall be inspected to determine whether they are cracked or otherwise damaged. Any damaged portions shall be removed and replaced as required by the owner.
All costs in connection with any such heating, bending, or straightening one for the convenience of the Contractor and all costs in connection with any repair or replacement required by reason of such heating, bending, or straightening shall be borne by the Contractor.
PLACING OF WELDED WIRE FABRIC
Carefully place fabric reinforcement and maintain in the position before and during placing of concrete.
ANCHORING DOWELS
All dowels shall be securely anchored in place by wire tying, etc, before starting placement of concrete.
COATING DOWELS FOR FUTURE EXTENSION
Exposed reinforcing bars and metal waterstops intended for bending with future work shall be protected from corrosion with two coats of "Bitumastic" coating. Before coating the dowels, two coats of Bitumastic Concrete Penetrant shall be applied on the surface adjacent to the dowels. When the dowels are coated, the coated concrete surface shall be included as an integral part of the dowel coating.
COMPLIANCE WITH STRENGTH REQUIREMENTS
COMPRESSIVE STRENGTH
Compliance with the specified compressive strength shall be measured by tests made on cylinders at an age of 28 days if fly ash or pozzolan is used for replacing part of the cement 90 days test cylinders shall be used.
STRENGTH TEST RESULTS
Strength test results shall conform to the following requirements.
REQUIREMENTS
FOR STRENGTH TEST RESULTS
ITEM
NO
|
TEST RESULTS
|
REQUIREMENTS
|
1.
|
Average of any 3 consecutive strength test results
|
Equal to, or greater than, specified strength
|
2.
|
For any strength test result
|
Not more than 1/3 of specified strength less than
specified strength
|
CONCRETE BELOW SPECIFIED STRENGTH
If the results of strength tests indicate that concrete does
not meet specified requirements, the concrete production shall be stopped until
corrective action is implemented to guarantee conformance with specification.
Contractor may be directed to take concrete cores and/or
make load tests, at his own expense, of any work that he has installed with
concrete not meeting specified strength requirements. If cores and/or load test
establish that such work in place does not meet requirements, Contractor shall
correct the work as directed without cost to the Owner.