1. SCOPE
This
specification covers the requirements for erection of structural steel for PLTU 1 Nusa Tenggara Timur, Ende, Nusa
Tenggara Timur, Indonesia.
2. REFERENCES
The
requirements contained in the latest editions of the following standards and
REKADAYA Specification shall form an integral part of the requirements of this
specification in the manner and to the extent specified herein.
ACI 117 Standard
Tolerances for Concrete Construction and Material
ACI 214R Recommended
Practice for Evaluation of Compression Test Result of Field Concrete
ACI 301 Specification
for Structural Concrete For Building
ACI 304 Recommended
Practice for Measuring, Mixing, Transporting and Placing Concrete
ACI 308 Recommended
Practice for Curing Concrete
ACI 311.5R Batch
Plant Inspection and Field Testing or Ready Mixed Concrete
ACI 315 Manual
of Standard Practice For Detailing Reinforced Concrete Structure
ACI 318 Building
Code Requirements For Reinforced Concrete
ASTM American
Society for Testing and Materials
ASTM C31 Practice
for Making and Curing Concrete Test Specimens in the Field
ASTM C33 Specification for Concrete Aggregate
ASTM C39 Test
Method for Compressive Strength of Cylindrical Concrete
ASTM C94 Ready
Mixed Concrete
ASTM C150 Specification
for Portland Cement
ASTM C172 Practice
for Sampling Freshly Mixed Concrete
SII Indonesian
Industrial Standard
SNI Indonesian
National Standard
SKI Indonesian
Construction Standard
JIS Japanese
Industrial Standard , Manufacturer’s
Specification
SKBI Indonesian
Standard for Building Construction
1801-00-S-05-XXX-001-0-0
Design
Specification For Civil, Structural and Architecture PLTU1 NTT
PLTU1 NTT contract Document, Section 4.4 Civil Works
3.
MATERIALS
Cement
Cement shall
conform to SII 0013-81, ASTM C150 or equivalent. Cement type I shall be used
for above grade work, cement Type II for Sub structure and cement type V for
all structure direct contact with sea water including wharf. Cement type II and
type V supplied directly by cement manufacturer
Admixtures
(1) Admixtures
to be used in concrete shall conform to the following standards or be an
approved equal;
Air-entraining
admixtures ASTM
C260
Water-reducing,
retarding and accelerating admixtures ASTM
C494
Pozzolanic
admixture ASTM
C618
(2) Admixtures
shall be the same composition as the
admixture used in establishing the required concrete proportions
(3) Accelerating
admixtures containing calcium chlorides shall not be used for reinforced
concrete
(4) In
High temperature or in chemical resistance such as acid, special treatment of
concrete mixed are required
Water
The mixing
water for the concrete shall be potable water, clean and free from injurious
amounts of oil, acid, alkaline and other deleterious materials, and conform to
ASTM C94. Non potable water may be used if mortar test cubes made with
non-potable water result in 7 days and 28 days strengths equal at least 90
percent of strength of similar specimen made with potable water. The strength
comparison shall be made on identical motar cubes,except for the mixing water,
prepared and tested in accordance with ASTM C109. Mixing water must not contain
more than 1000 ppm of sulfates, 500 ppm of chlorides and 2000 ppm of silt
Aggregates
The
aggregates for concrete shall conform to the requirements given in ASTM C33 and
SKI (Indonesian Construction Standard)
Reinforcing Bar
Reinforcing
steel bar and wire fabric shall conform to the ASTM A615, fy = 4000 kg/cm2 for
deformed bar and fy = 2400 kg/cm2 for plain bar.
4. STORAGE OF MATERIALS
4.1 Cement shall be
storage in weather tight building, Which will provide protection from moisture
and contamination. Sack of cement shall no be stacked in piles exceeding 13
stack. When storing cement in sacks the floors shall be a minimum of 30 cm
above ground level and shall be paved with concrete and cover with plastic sheet
to prevent the absorption of water.
4.2 Aggregate stock
shall be arranged and used in a manner to avoid excessive segregation and to
prevent contamination with other materials or with other sizes of aggregates.
4.3
Sand shall be allowed to drain
until it has a uniform moisture content before it is used.
4.4
Reinforcing steel , wether
fabricated or not, shall not be placed directly on the ground. Care shall be
taken to prevent reinforcing steel from being deformed during storage.
4.5
Admixtures shall be stored as
recommended by themanufacturer
5. PROPORTIONING
5.1
Strength of concrete
The
minimum compressive strength of concrete and maximum water-cementious ratio
shall be follow. Concrete mix design shall be determined in accordance with the
provisions in section 16.2
Classification
of concrete grade
|
Compressive Strength At 28 days (Cylinder
specimen)
|
Application
|
|
f’c = 500 kg/cm2 (C50)
|
For prestress concrete structure (eg. Spun
piles, sheet piles)
|
|
f’c = 300 kg/cm2 (C30)
|
For Important structure and foundation (chimney,
turbine generator, jetty, boiler and Cooling water pump house)
|
|
fc = 250 kg/cm2 (C25)
|
For all concrete work in common building and
structures of the power plant, unless otherwise specified
|
|
fc = 150 kg/cm2 (C150)
|
For lean concrete as specified and for
un-reinforced concrete or otherwise noted
|
5.2
Slump Concrete.
(1)
Slump of concrete shall be in
accordance with table 1
Table
1; Slump of concrete
|
Type
of Construction
|
Maximum
(mm)
|
Minimum
(mm)
|
|
Reinforced
footing
|
75
(100)*
|
25(50)*
|
|
Plain
footing and substructure wall
|
75
(100)*
|
25(50)*
|
|
Slab,
beams
|
100(150)*
|
25(75)*
|
|
Columns
& Wall
|
125(150)*
|
25(75)*
|
|
Bored
Pile
|
200**
|
170**
|
|
|
|
|
* the value in the parentheses
are for concrete to be placed by pumping methods
** Shall be based on the
requirement of concrete device
(2)
Maximum Slump shown in table 1
may be increased 25 mm for methods of consolidation other than vibration
5.3 Maximum size of
coarse aggregate
Unless otherwise specified or approved by REKADAYA, the maximum
nominal size aggregate shall not exceed
;
(1)
one-fifth of the narrowest
dimension between sides of forms
(2)
one-third of the depth of slabs
(3)
Three-quarters of the minimum
clear spacing between individual reinforcing bars
(4)
200 for bored pile
5.4 Selection of
proportions
(1) The proportion of ingredients shall be
selected in accordance with requirements given in ACI211.1 and to produce proper place
ability, durability, strength and other required properties
(2) All proportions for concrete shall be approved by
REKADAYA
(3) As a rule proportion of ingredients shall be
determined by concrete mix design
6. MIXING
6.1 The concrete shall be concrete mix design
which shall be mixed in accordance with ASTM C94, concrete mixer used shall be
portable type which capable of combining the aggregates, cement and water
thoroughly into a uniform mass within the specified mixing time and of
discharging the concrete without harmful segregation
6.2 Except
as provided in section 6.4 below, batches of 0.75 m3 or less shall be mixed for
not less than 1 minute. The mixing time shall be increased 15 second for each
0.7 m3 of fraction there of additional capacity. At least three-quarter of the
required mixing time shall take place after of the last mixing water has been
added
6.3 A
shorter mixing time may be permitted if performance tests indicate that the
time is sufficient to produce uniform concrete
6.4 In
hot weather, mixing time shall be held to the minimum which ensure adequate
concrete quality and uniformity. Mixer drums and blades shall be checked
frequently during hot weather and the interior of the mixer shall be free of
accumulations that interfere with mixing action
6.5 Tolerance
for measuring ingredients shall be as specified
in table 2
6.6 Use
of air-entraining admixture and other chemical admixture shall be made in
accordance with ASTM C494
Table 2 : Typical Batching Tolerances
(Reference :
ACI 304, Table 3.1.2)
|
Ingredient
|
Batch weight greater than 30 % scale
capacity
|
Batch weight less than 30 % scale capacity
|
|||
|
Individual
Batching
|
Cummulative
batching
|
Individual
Batching
|
Cummulative
batching
|
||
|
Cement and other
Cementious Material
|
A1 percent or A 0.3 percent of scale capacity whichever greater
|
Not less than
required weight or 4 percent more than required weight
|
|||
|
Water (by volume
or weight), percent
|
A 1
|
Not Recommended
|
A 1
|
Not Recommended
|
|
|
Aggregate,percent
|
A2
|
A1
|
A 2
|
A0.3 percent of scale
capacity or A3 percent of required
cummulative weight whicever is less
|
|
|
Admixture (by
volume or weight),percent
|
A3
|
Not Recommended
|
A3
|
Not Recommended
|
|
7. TRANSPORTATION
7.1 Concrete shall be transported from the potable
mixer to the place of final depositby the appropriate method
7.2 The
Method shall be such that will prevent segregation, loss or contamination of
the ingredients
7.3
The Maximum time from concrete
mixing to final placing of concrete shall be as follow :
Table 3 : Time limit from
concrete mixing to final placing of concrete shall be as follows ;
|
Concrete Grade
|
Ambient Temparature
|
Maximum Time
|
|
|
|
(in oC)
|
(in Min)
|
|
|
High grade Concrete (f'c > 270 kg/cm2)
|
25
|
45
|
|
|
> 25
|
30
|
||
|
Ordinary grade Concrete (f'c < 270 kg/cm2)
|
25
|
60
|
|
|
> 25
|
45
|
||
|
Concrete for bored pile
|
25
|
Subcontractor shall be propose and provide
concrete mix design for determining the time limits for REKADAYA aprpoval
prior executing the work
|
|
|
>25
|
|||
8. PLACING
8.1
Prior to concreting the interior of the forms shall be thoroughly clean and be
free from all foreign matter and accumulated water. The interior of wooden
forms shall be wetted prior to concreting
8.2 Concreting shall be deposited as nearly as
practicable at its final position to avoid segregation due to re handling or
flowing
8.3 Concrete shall be placed at such a rate that
concrete it plastic at all times and flows readily into the spaces between the
bars
8.4
Concrete that has taken its initial set or been contaminated by foreign
material shall be not used
8.5 Concrete shall be placed so as to avoid
segregation of the material. Chutes or through shall be used in placing
concrete so as to prevent a free fall through steel mesh obstruction in excess
of 1.2 m high
8.6 Maximum
height of concrete placing per one layer shall not exceed 5.0 m
8.7 All
concrete shall be thoroughly consolidated by suitable means, preferably by
vibration during placing and shall be thoroughly worked around reinforcement,
anchor bolts and other embedded fixtures and into the corners of the forms. An
adequate number of spare vibration shall be kept always at the site during all
concrete placing operation
8.8 No
concrete shall be poured without approval form REKADAYA
8.9
Where joints are to be made the
surface of the hard concrete shall be cleaned thoroughly, roughened and all
laitance shall be removed by brushing or chipping and treated with a thin layer
of near cement before additional fresh concrete is placed
8.10
The concrete surface of
vertical joints shall be thoroughly wetted and coated with neat cement grout
immediately before placing adjoining concrete
8.11
Grooves shall be formed at
construction joints as directed on the drawing
8.12
All horizontal surfaces, unless
otherwise specified, shall be given a wooden trowel finish. Where non-skid
surface are required the surfaces shall be broom finished.
8.13
Concrete showing structural
defects shall be demolished and replaced. Concrete showing only surface defects
shall be chipped out to sound concrete, treated with epoxy bonding agent and
then patched with concrete of rich mortar or epoxy mortar. The repair method
for above shall be subject to the approval from REKADAYA
8.14
Holes left by withdrawal of tie
rod shall be filled solidly with cement mortar and be made flush
8.15
Reinforced concrete must not be
placed directly upon the ground. Base could be of either a blinding concrete or
polyethylene sheeting of suitable thickness
8.16
Location of anchor bolt and
other item to be embedded in concrete such as insert, hanger, pipe support,
pipe sleeve, conduit drain etc. shall be checked using precision instrument during
concreting
8.17
In Wall concrete shall be
placed in horizontal layers of 30 – 45 cm thickness to maintain a level surface
stopping only at panel or section
9. CURING
9.1 All
concrete surface shall be kept wet at least 7 days after placing except that
high early strength concrete shall be maintained for at least 5 days.
9.2 The
concrete surfaces not in contact with the forms shall be kept continuously
moist for 24 hours by covered with burlap, cotton fabric or other suitable
material such as a curing compound, immediately after finishing the surface
9.3 The
covering material shall remain in place during the full curing period. The
covering material may be removed when the concrete has hardened sufficiently,
provided that the surface is immediately covered with sand, straw or other
similar material. In either case, the materials shall be kept thoroughly wet
during the full curing period.
9.4 Wood
forms in contact with the concrete shall kept wet during the curing period and
to prevent moisture loss by sealing concrete surface with waterproof paper,
plastic sheet.
9.5 Curing
shall be in accordance with the appropriate provision of ACI 301 and 308 unless
noted otherwise herein
9.6 In
hot weather requirement when the air temperature is at or above 80o
F
(28o C), provisions for windbreaks, shading, foq spraying,
sprinkling or ponding shall be made in advande to the delivery of any concrete.
Such protective measure shall be as quick as concrete finishing and hardening
operation allow. All work shall conform to ACI 305
9.7 The Curing compound
shall be applied in accordance with the manufacturer’s directions
9.8 No Load shall
be placed on the concrete during the curing period.
10. REPAIRING DEFECTIVE CONCRETE
Subcontractor
shall be immediately notified if defects, such as honey comb or detrimental
cracking are found in the concrete after the forms are removed. All defects in
the concrete shall be repaired in accordance with the requirement given in ACI
301, chapter 9 and the following stipulations ;
(1)
All defect detrimental to
structural strength, durability and water tightness shall be repaired by the
method approved.
(2) All honey comb and other defective concrete
shall be removed down to sound concrete. The sound surface shall be inspected
by REKADAYA prior to patching as specified in section 8.13.
11. FORMWORK
All forms shall be leak proof
and of sufficient strength to sustain construction and concrete loads without
excessive deflection. Design of the form work as well as its construction shall
be done to attain safe installation, removable without any damage to the
concrete and shall be approved by REKADAYA.
Before concreting is
commenced the forms shall be thoroughly
cleaned and free from all dust, dirt and other debris. Temporary openings shall
be provided where necessary to drain away
water and rubbish.
All formwork, whether wood or
steel, shall be fixed in perfect alignment and securely braced to withstand
displacements and deflections due to construction load, such as vertical,
horizontal and impact construction loads.
Where necessary to maintain the
specified tolerances the formwork shall be cambered to compensate anticipated
deflection caused in the formwork by the weight and pressure of the fresh
concrete and by construction loads. The tolerances for the installation of the formwork
shall be as specified by ACI 347
Suitable molding or chamfer
strips shall be placed in the corners of column, beam and wall forms where
concrete will be exposed to view
All anchor bolts, pipes, angle,
insert plates etc. to be embedded in or through the concrete shall be fixed
firmly in the forms which shall be cut neatly and accurately for a tight fit
The internal surface of the
form shall be coated with form oils or other releasing agents approved by
REKADAYA prior to installation
Temporary opening shall be
provided at the base of column and wall forms, and at other points where
necessary to facilitate cleaning and inspection immediately before the concrete
is deposited
Removal of forms
(a) Forms
shall be removed in such manner as to ensure the complete safety of the
structure. Where the structure as a whole is adequately supported on shores,
side forms of beams, girders, columns and similar vertical forms may be removed
after a lapse of 3 days during which the air temperature exceeds 10 oC or when the
compressive strength of the concrete reaches 50 kgf/cm2
(b) Forms and
shoring in the formwork used to support the weight of concrete in beams, slabs
and other structural members shall remain in place until structure attains
sufficient strength to support the dead load and other imposed loads.
Field-cured specimens shall be used to estimate the structural strength.
(c) Forms other
than mentioned above and shoring shall remain in place for period of time not
less than those shown in Table. 4 . If high-early-strength concrete is used
this perio may be reduced if approved by REKADAYA
(d) After removal
of forms for the cable pit the concrete surface shall be cleaned and all burns
and any injurious obstruction shall be removed
All
form surface shall be cleaned before re-use
Table 4 : Schedule Removal of Forms
|
|
Clear Span Between support (CS)
|
LL < DL
(Days)
|
LL > DL
(Days)
|
|
|
Beam and Girder Soffit
|
CS < 3 m
|
7
|
4
|
|
|
3 m < CS < 6 m
|
14
|
7
|
||
|
6 m < CS
|
21
|
14
|
||
|
Floor slab
|
CS < 3 m
|
4
|
3
|
|
|
3 m < CS < 6 m
|
7
|
4
|
||
|
6 m < CS
|
10
|
7
|
Where ;
CS ; Distance in meter between supports, referred to
structural supports and not to temporary formwork or shore
LL ; Live
load
DL ; Dead
Load
12. REINFORCING BAR WORK
Reinforcing shall be detailed
and bent in accordance with ACI 315. Heating bar to facilitate bending will not
be permitted. All reinforcing bar shall be bent cold before being placed in
position. Reinforcing steel shall not be bent or straightened in a manner that
will injure the material. Bending or straightening of bars after their
embedment in concrete will not be permitted.
Reinforcing bars shall be free
from mud, dirt, loose mill scale, oil, grease and any other foreign matters
that reduce the bond between the bar and the concrete.
All reinforcing bars shall be
placed exactly as shown on the drawings and be supported by an adequate number
of small precast mortar block with with tie wire-cast-in or with other approved
chair and spacer. The strength of the mortar shall be same or greater than that
of the concrete.
Reinforcing bars shall be tied
adequately at the intersection with annealed steel wire and be held in position
rigidly by using spacer, chair, or hanger to prevent displacement by
construction loads or by the placing of concrete.
Splices shall be located as
shown on the drawings. Additional splices no shown on the drawings shall be
subject to the approval of REKADAYA
Reinforcing bar shall not be
spliced in a line at one location but staggered at a distance equal to 40 times
of the bar diameters as a minimum
Length of lap for splicing and
concrete to reinforcing bar shall be as indicated on the drawing and conform to
the requirements of ACI 318
Bars may be moved as necessary
to avoid interference with other reinforcing bar, conduit or embedded items
Splicing of reinforcing bars by
welding will not be permitted under any circumstances.
Fabricating and splicing
tolerances shall be specified in ACI 301 section 5.6 as follow.
5.6
Fabrication and splicing tolerances
5.6.1 Reinforcing bars shall be
fabricated in accordance with the standard fabrication tolerances in fig.
4 and 5 of ACI 315
5.6.2 Reinforcement shall be placed to
the following tolerances
tolerance
mm
Clear distance
To formed soffit
………………………………………………………. A6.35
To other formed surfaces …………………………………………… A6.35
Minimum spacing between bar ………………………………………… A6.35
Clear distance from unformed surface to top
reinforcement
Members 8 in deep or less ………………………………………... A6.35
Member more than 8 in, deep but less than 24 in deep…………...
-6.35,+12.7
Member 24 in deep or greater
……………………………………….. -6.35, +25.4
Uniform spacing of bars but the required number of
bars shall not be reduced A50.8
Uniform spacing of stirrups and ties, but the
required number of stirrups and ties shall not be reduced
………………………………………... A25.4
Longitudinal location of bends and ends of ends of
reinforcement ;
General ………………………………………………………………… A50.8
Discontinuous ends of members ……………………………... A12.7
Length of bars laps …………………………………………. A38.1
Embedded length
For bar size No. 3 through 11 ……………………………... A25.4
For bar size No. 4 and 18 ……………………………... A50.8
5.6.3
When
it is necessary to move bar to avoid interference with other reinforcement,
conduits or embedded items exceeding the specified placing tolerances, the
resulting arrangement of bars shall be subject to acceptance
13. ACHOR BOLT AND EMBEDDED PLATE
SETTING
Anchor bolts and other items to
be embedded in concrete such as insert, hanger, pipe support, pipe sleeves,
conduit drain etc. shall be placed and secured in position before any concrete
is paced. The securing of these items in position by welding reinforcing bars
will not be permitted.
Anchor bolt setting for the
foundation shall be in accordance with the following stipulation :
Anchor bolt with template
(1)
When setting anchor bolts with
templates, supports shall be provide so as to avoid any movement of the anchor bolts templates at
the time of concrete placing.
(2)
Supporting frame for setting
template shall not be fixed on the reinforcement bars or forms.
(3)
Tolerance of template setting
shall be as follow ;
|
Position
|
Orientation
|
Level
|
Verticallity
|
|
+/- 3 mm
|
+/- 2mm on
the periphery
|
+5 mm – 0
mm
|
(L bolt /
300 ) mm
|
Anchor bolt with gauge plate
(1)
Gauge plates shall be used for
direct anchor bolt setting for steel structure etc, where template are not used
(2)
Gauge plate shall be firmly
fixed to the forms
(3)
Tolerance for gauge plate
setting shall be as follows :
Position : A
3
mm
Level : +
5 mm
- 20 mm
Anchor bolt with Anchor box
(1)
Size and depth of anchor box
shall be according to the drawings
(2)
Tolerance of anchor box setting
shall be as follow ;
Position :
A 10 mm
Level : -
0 mm
+ 20
mm
(3)
Anchor bolt shall be set after the inside of anchor
box is cleaned and drained
(4)
Filling materials for the
anchor box shall be non shrink grout, mixed and installed in accordance with
manufacture’s recommendation
(5)
When specification of machine,
equipment etc. require the use non shrinking cement to filling anchor box,
contractor shall use it and submit to REKADAYA the specification catalogs
and/or samples of non-shrinking cement for approval.
Thread on anchor bolts shall be
protected at all times against damage.
14. GROUTING
Base
plate and base of structure, after erection, shimming and leveling shall be
grouted using a non-shrink grout unless otherwise specified herein.
All
grout shall be mixed and installed in accordance with manufacturer’s
recommendation. Surface against which grout
will come in contact with shall be clean and free of all deleterious
coating. Concrete surface to be in
contact with non shrink non staining grout shall be completely saturated with
no standing water immediately prior to the installation of the grout.
Shims
shall not be incorporated in the final structures unless specifically
recommended to be left in place by the manufacturer of the equipment being
supported. Shim shall be removed only after the first placement of grout has
obtained sufficient strength to support the equipment or structure. The first
placement of grout has obtained sufficient strength to support the equipment or structure. The void left by
removal of shims shall then be filled with a grout mix similar to the initial
mix.
Grout
mix water non-shrink shall be limited the amount required to procedure the
stiffest consistency that may be efficiently used.
Finishing
and Curing of grout :
(1) The exposed
grout shoulders shall be troweled to provide as smooth surface and shall be
sloped from base to edge of foundation for drainage
(2) The exposed
area of fresh grout shall be immediately covered with clean rags wet with
potable water
(3) When grout is
sufficiently hard, remove forms and leveling shims (unless otherwise noted).
Damp pack void left by shim removal, using a stiff mixture of identical grout.
All
anchor bolt sleeves and holes shall be cleaned and completely filled with
non-shrink grout. Anchor bolt sleeves and holes when used with special grout
shall be handled per grout manufacturer’ recommendation
15. CONSTUCTION JOINT AND EXPANSION
JOINT
Construction shall be
monolithic whenever practicable. If monolithic construction is not practicable,
properly designed construction joints are required.
All construction joints shall
be shown on the design drawing. Joints not shown on the drawings shall be so
made and located as to least impair the strength of the structure and shall be
approved by REKADAYA.
Reinforcing steel and mesh
shall be continued across all joints except expansion joints. All expansion
joints where it is required to transfer loading from one side of the joint to
the other or to maintain surface alignment (slab or grade) shall be provided
with smooth dowels with sleeves on one end to allow sliding. Expansion joints
shall be 12 mm thickness joint filler to separate slab on grade on vertically
surface. Joint sealer shall be provided where appropriate and necessary to
assure foreign substances are prevented from entering the joint.
Where water-tight construction
is required, construction joints shall have water stop.
16. TESTING
AND QUALITY CONTROL
Concrete mix design
(1) Prior
to the commencement of concrete works, contractor shall perform mix design to
determine the kinds and mix proportion of cement, coarse aggregate, fine aggregate,
water and admixtures
(2) Result
of the mix design shall be reported to REKADAYA in the prescribed form shown in
the table 5 . attached herewith
Table 5 :
Result of Mixing Design of Concrete
|
Specimen No.
|
#1
|
#2
|
#3
|
|
|
Stregth 28 days
(kg/cm2)
|
|
|
|
|
|
Cement Type
|
|
|
|
|
|
Maximum size of
coarse aggregate (mm)
|
|
|
|
|
|
Slump (cm2)
|
|
|
|
|
|
Air Content (%)
|
|
|
|
|
|
Fine Aggregate
ratio
|
|
|
|
|
|
Unit water
content (kg/cm2)
|
|
|
|
|
|
Absolute Volume
(l/m3)
|
Cement
|
|
|
|
|
Fine Aggregate
|
|
|
|
|
|
Coarse Aggregate
|
|
|
|
|
|
Weight (kg / m3)
|
Cement
|
|
|
|
|
Fine Aggregate
|
|
|
|
|
|
Coarse Aggregate
|
|
|
|
|
|
Admixture (cc/m3
or kg/m2 )
|
|
|
|
|
|
Test result for
compressive (kg/m2)
|
7 days age
specimen
|
|
|
|
|
14 days age
specimen
|
|
|
|
|
|
28 day age
specimen
|
|
|
|
|
|
Maximum pre-placing
time limit
|
</= 25 oC
|
|
|
|
|
> 25 oC
|
|
|
|
|
|
R E M A R K S
|
|
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Compressive Strength Test
Compressive
strength test shall be carried out in accordance with the following procedure :
(1) Compressive
strength test shall be performed by an apparatus approved by REKADAYA and shall
be in accordance with ASTM C-39
(2) Obtaining
samples of concrete for making compressive strength tests specimen shall be in
accordance with ASTM C 172
(3) A
minimum of four specimens shall be made in accordance with ASTM C 31 unless otherwise
specified
(4) Three
specimen shall be made for each test at the given age. At least three specimen
shall be made for each 50 cubic meter or fraction thereof; for each mix design
of structural concrete to be placed in any one day.
(5) The
age of strength test unless otherwise specified shall be 7 days and 28 days
(6) The
strength of the concrete shall be considered satisfactory if the following
requirements are met ;
(a)
The average strength value at
28 days age of all specimens used in three consecutive strength tests (average
of six or more cylinders) is equal to or exceeds the specified strength
(b)
No individual strength falls
below the specified strength by more than 35 kg/cm2. If concrete compressive
strength do not meet the specification. REKADAYA shall stop concreting the
facility (foundation or structure) until corrective measures are taken
Slump Test
(1) Slump
test shall be made in accordance with ASTM C 143 unless otherwise specified
(2) Frequency
of slump test shall be determined based on the weather conditions and on the
operating condition of the mixer, however the slump test shall be made at least
once for each set specimen.
(3) Unless
otherwise shown on the drawing, the slump shall be accordance with table – 1
Air content test
Air content
test shall be carried out if requested by REKADAYA and in accordance with the
requirements given in ASTM C 138, ASTM C 173 or ASTM C 231
Water filling test for concrete
ponds
Unless
otherwise shown on the drawings any water filling test shall be carried out
before back filling the concrete ponds. Water shall be filled to the highest
level expected and maintained for minimum of 24 hours. Concrete ponds shall be
filled only after obtaining the approval of REKADAYA
17. HOT WEATHER CONCRETING
Concrete work in hot weather shall be in accordance with ACI 305.