WPT & RCPT Testing Procedure
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Transcript of WPT & RCPT Testing Procedure
7/21/2019 WPT & RCPT Testing Procedure
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WATER PERMEABILITY TEST
As per Contract SpecificationVolume 5 Section3 Cl. 3.6.1 (17) & DIN 1048: -
Test Procedure:
The permeability of concrete will be verified by the following procedure:
i. After 28 days of curing, test specimen will be fitted in a
machine such that the specimen can be placed in water under
pressure up to 7 bars.
ii. At first a pressure of one bar is applied for 48 hours, followed
by 3 bars for 24 hours and 7 bars for next 24 hours.
iii. After the passage of the above period, the specimen is taken out
and split in the middle by compression applied on two round
bars on opposite sides above and below.
iv. The water penetration in the broken core is measured with scale
and the depth of penetration assessed in mm at three places of
maximum penetration and average of three values is taken as
Water Penetration (max permissible limit 25 mm as per
Outline Construction Specification and 10 mm as per
Outline Design Specification).
However, as per International Standards (DIN1048) the specimen shall be kept
under 5 bar pressure for 72 hours and water penetration shall be determined as
above.
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RAPID CHLORIDE ION PENETRATION TEST
As per ASTM C1202-05:
This test method covers the determination of the electrical conductance of
concrete to provide a rapid indication of its resistance to the penetration of
chloride ions.
This test method consists of monitoring the amount of electrical current
passed through 2-in. (51-mm) thick slices of 4-in. (102-mm) nominal
diameter cores or cylinders during a 6-h period.
A potential difference of 60 V dc is maintained across the ends of the
specimen, one of which is immersed in a sodium chloride solution, the other
in a sodium hydroxide solution. The total charge passed, in coulombs, hasbeen found to be related to the resistance of the specimen to chloride ion
penetration.
As per various studies, RCPT values of concrete stabilize at about 90 to 100
days. Thereafter reduction in RCPT value is insignificant.
Apparatus:
1. Vaccum Saturation Apparatus (Vaccum Dessicator, Vaccum Pump,
Beaker1000ml cap., Vaccum gauge)
2.
Rapid setting sealer3. Silicon Sealant
4. Applied Voltage Cell
5. Temperature measuring device
6. Voltage Application and Data readout apparatus
Chemical Used : -
Sodium Chloride Solution - 3.0 % by mass (reagent grade) in distilled water.
Sodium Hydroxide Solution - 0.3 N (reagent grade) in distilled water.
Procedure: -
Sample taken out from curing tank after 90 days should be cleaned with the
help of carborandom stone (Chemical application face).
Sealer to be applied on the peripheral of the specimen.
Specimen should be placed in the closed desiccator and air sucked for a
period of 3 hrs with the help of Vacuum Pump.
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Distilled water introduced into the desiccator to submerge the specimen.
Again Vacuum Pump runs for 1 hr. for filling the pores with distilled water.
Fully immersed Specimen kept for 18 hrs. soaking in the desiccator.
Specimen taken out from the desiccators, check the diameter of specimen
and fixed into the testing mould with silicon sealant to prevent leakage.
Chemicals poured into the mould.
Electrode connected with the mould with constant power supply @ 60 volt
DC.
Charge recorded for 6 hrs. @ an interval of every half an hour.
Calculation of Result
Qs = 900 (I0 +2I30 +2I60 +………. +2I300 + 2I330 + I360)
where:
Q = charge passed (coulombs),
Io = current (amperes) immediately after voltage is applied, and
It = current (amperes) at t min after voltage is applied.