GENERAL REQUIREMENTS
Inspection program shall be submitted for inspecting items
and activities affecting quality. The following items shall be included in the
inspection program :
- Pre-placement inspection of area to receive concrete which
includes but is not limited to formwork, reinforcing steel, embedded items, and
final cleanup
- Concrete placement
- Finishing and curing
- Formwork removal
- Concrete repair
Field control tests shall include all material and concrete
test required, but not be limited to the following :
- Slump tests (ASTM C143), every 50 m3
- Air Content Tests (ASTM C231), every 50 m3
- Aggregate Gradation Tests (ASTM C136), weekly
- Specific Gravity Tests (ASTM C127), weekly
- Organic Impurities (ASTM C40), daily
- Surface Moisture (ASTM C70), daily
- Concrete Temperature every 50 m3
The Contractor shall provide at his own expense an approved
independent material and concrete Testing Laboratory fully equipped to carry
out all testing required to meet the requirements of the ASTM & ACI
Specifications. Evidence shall be provided that the equipment and procedures
comply with ACI or other approved standards and its equipment are regularly
checked, calibrated and adjusted for accuracy. Field tests shall be performed
by the Contractor. The Contractor shall be responsible for conducting field
test, preparing test specimen and supplying material for laboratory testing
with the quantities and frequencies as specified herein.
The Contractor shall provide the services of qualified
employees as required for making the field tests, preparing, storing, curing,
and handling test specimen and for delivery of materials tests specimens to the
independent laboratory.
All field control tests and the preparation of concrete test
specimens shall be made by the contractor's employees. Tests shall be made in
the presence of the Owner's representative and when directed.
Frequencies specified for each field control test are
minimum. If any additional field control tests are necessary, in the opinion of
the Owner, the Contractor shall carry out the additional tests or supply the
material for additional without any additional cost to the Owner.
Up-to-date records shall be kept by the Contractor of
positions in the works of every batch of concrete, of its grade and of all test
cylinders, core, or other specimens taken. Copies of these records shall be
supplied to the Owner at weekly intervals or upon request by the Owner.
The Owner on site shall have the authority to stop all
further concrete work until acceptable test results are forth coming.
AGGREGATE GRADATION
Fine and coarse aggregate shall be sampled and tested in
accordance with ASTM D75 and C136.
SLUMP
Slump tests (ASTM C143) shall be made at the same frequency as the compression test cylinders and shall be made from the same batch of concrete and from the first batch mixed each day. Each set of compression test cylinders shall be marked or tagged with the slump.
Slump tests (ASTM C143) shall be made at the same frequency as the compression test cylinders and shall be made from the same batch of concrete and from the first batch mixed each day. Each set of compression test cylinders shall be marked or tagged with the slump.
AIR CONTENT
An air content test shall be made from the first batch mixed
each day and from each batch of concrete from which concrete compression test
cylinders are made. Air content shall be determined in accordance with ASTM
C231.
Each set of compression test cylinders shall be marked or
tagged with the air content.
CONCRETE TEST CYLINDERS
Production Test
To verify the compatibility of the Laboratory Design Mixes
with the working conditions on site, the Contractor shall carry-out trial mix
under full scale production conditions.
Procedures and number of test cylinder to be tested shall be
as for the Laboratory Design Mix.
Trial mix under full scale production conditions shall be carried out at least
four weeks before commencing any concreting in the works, under supervision of
the Owner.
Concrete Testing
Cylinder molds, curing and test mentions shall be in
accordance with ASTM C31, C39, C143, C172, C231 and C511. Contractor shall
provide cure boxes for storing test specimens, meeting the temperature and
other requirements of ASTM C31.
The testing laboratory will provide cylinder molds and
instructions to Contractor for properly making, storing and shipping job
concrete test cylinders and instructions for checking percentage of air
entrainment and for making slump tests.
Production Control of Concrete
Control of concrete shall be by Contractor as follows:
Contractor shall make all production concrete test cylinders,
as specified in the following, from fresh samples of concrete taken on site,
from discharge of stationary mixers, pump concrete machines, truck mixers or
truck agitators. Locations for taking samples shall be acceptable to the Owner.
Making of test cylinders shall be included slump test followed by preparation
of storing, packing, and delivery of test cylinders to Testing Laboratory with
required data as to materials, water-cement ratio, proportions, slumps etc.
Schedule of Production Concrete Test Cylinders
|
Total cylinders required from a sample representing each
50 cu m of concrete, or from each day's pour if less then 50 cu m.
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Cylinders
For
Strength Test At
|
||
|
3
days
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7
days
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28
days
|
|
|
3 sets of 2 each - Total 6
|
2
|
2
|
2
|
NOTE :
1) One set of 2 cylinders comprises a strength test.
2) Add 90 days sets, when fly ash or pozzolan is used.
Unless otherwise indicated, the Contractor shall at his own expense, furnish equipment for and shall check the slump of concrete and air content of air-entrained concrete by direct measurement of fresh samples of concrete taken on site from discharge of stationary mixers, pump Crete machines, truck mixers or truck agitators. Equipment shall consist of slump cones, one air meter and one or more pocket-type air indicators. Locations of samples for testing slump and air entrainment shall be the same as for samples for test cylinders.
1) One set of 2 cylinders comprises a strength test.
2) Add 90 days sets, when fly ash or pozzolan is used.
Unless otherwise indicated, the Contractor shall at his own expense, furnish equipment for and shall check the slump of concrete and air content of air-entrained concrete by direct measurement of fresh samples of concrete taken on site from discharge of stationary mixers, pump Crete machines, truck mixers or truck agitators. Equipment shall consist of slump cones, one air meter and one or more pocket-type air indicators. Locations of samples for testing slump and air entrainment shall be the same as for samples for test cylinders.