6
©
Germann Instruments, Inc.
Test Smart – Build Right
©
The software permits specimens with diameters other than 95 mm to be tested. The Proove’it
©
software
will automatically adjust the Coulombs for the actual diameter of the specimen to Coulombs for 95 mm
diameter specimens according to ASTM C 1202.
The specimen is positioned in the PR-1000 standard measuring cell, containing a fluid reservoir at each
face of the specimen. For the ASTM / AASHTO test one reservoir is filled with a sodium chloride (3.0%
NaCl) solution, the other with a sodium hydroxide (0.3 N NaOH) solution. For testing effectiveness of
membranes, the face of the specimen containing the membrane is placed in the NaCl reservoir.
The reservoir containing the NaCl is connected to the negative terminal and the NaOH reservoir to the
positive terminal of the Proove’it
©
Microprocessor Power Supply unit.
The Proove’it
©
software (ProovePC) is installed in a PC or laptop with Windows 10, and the test is run
after the required parameters have been entered.
If desired, the temperature can be monitored with a probe inserted in the NaCl reservoir. Should the
temperature of the solution exceed 90°C, the test will be automatically interrupted to avoid boiling. The
PR-1100 cell will avoid heating effects with its cooling ribs. The consequence of overheating is that the
relative Coulombs measures will be higher.
The cells may be started up at different times and its time of testing may also be chosen individually.
1.4
ASTM C 1760 using the Proove´it Cell PR-1200
(
See figure 3.b
)
The
Proove’it
©
system can also be used as specified in ASTM C 1760 for measuring the bulk electrical
conductivity of hardened concrete, which has a theoretical relationship to the diffusion coefficient of
chloride ions in the concrete
[17][18]
. Experimental data
[19][20]
confirm that there is a correlation between the
bulk electrical conductivity and the apparent chloride diffusion coefficient as measured by the non-
electrical methods ASTM C 1556 “Test Method for Determining the Apparent Chloride Diffusion of
Cementitious Mixtures by Bulk Diffusion” or NT BUILD 443 “Concrete, Hardened: Accelerated Chloride
Penetration”. These two methods require, however, a minimum ponding period of the specimen of at
least 35 days for natural diffusion to take place. The apparent chloride diffusion coefficient allows service
life estimation using Fick’s Second Law of Diffusion.
With the ASTM C 1760, water saturated cylindrical specimens, 100 mm in diameter by 200 mm length, are
used as a standard. For cores, the trimmed core length has to be between 100 and 200 mm. A 3% NaCl
solution is used in both chambers of the testing cell and the testing takes place at 60 V-DC. The current is
recorded on the screen after 1 minute of test to the nearest 0.1 mA.
The part number of the cell required to perform this test is PR-1200. For this testing procedure, the cells
are mounted with two spacer rings with appropriate holes, spacer distance pieces (for 200 mm long
specimens) and four threaded rods with nuts and washers (
See figure 3.b
).
NOTE:
To ensure quick, trouble-free and watertight assembling of the cells, the recommended size of
the specimens for the Proove’it is 100 mm in diameter by 50 mm thickness and use the B-Gasket. For
other diameters, ranging from 93 mm to 104 mm, matching gaskets are available for the Proove’it cells
(
See table 2
).
