SHRP-A-379 traducir

pressed. Otherwise, measure and record the peak axial load and recoverable vertical
deformation for the load interval from the last five cycles. Then calculate the ECS modulus
as outlined in section 11.3.3.
NOTE 5.--Typically, to achieve a strain level of 100 + 5 #strain, a dynamic load approximately 4000 N is
required. Once the load has been adjusted, use the same loads for subsequent measurements for the same specimen
after the conditioning cycles.
NoTE 6.--Do
specimen.
not exceed 250 load cycles when performing the ECS modulus test. This will damage the
10.3.6 Remove the load from the specimen after the last load cycle. Check that the
inlet and outlet gauges are closed.
10.4 Vacuum
valve.
10.4.1 Check that the bypass valve is open. Select vacuum with the vacuum-water-air
10.4.2 Open the vacuum valve and close the bypass valve. Apply a vacuum of
510 mm of Hg for 10 min.
10.4.3 Open the bypass valve.
10.5 Wetting
10.5.1 Maintain the temperature of the environment chamber at 25 + 0.5°C.
Establish the temperature of the distilled water source at 25 + 3°C (room temperature).
Open the bypass valve.
10.5.2 Select water flow from the vacuum-water-air valve. Turn on the vacuum and
adjust using the vacuum regulator until a level of 510 + 25 mm of Hg (as measured by the
outlet gauge) has been reached.
10.5.3 Wait for one minute or until distilled water has been drawn into the tubing
and the system. Close the bypass valve so that the distilled water is pulled through the test
specimen for 30 + 1 min.
10.6 Coefficient of Permeability of Water Flow
10.6.1 Decrease the vacuum level to approximately 40 kPa (5.8 psi) differential
pressure by adjusting the vacuum regulator. Record the water flow through the test specimen.
Record the pressure differential reading.
10.6.2 Repeat the procedure described in section 10.6.1 for four different pressures.
The pressures selected will vary depending on the void content of the specimen being tested.
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