Q-see man inter'l Resitest-400M User manual

Resitest-400M
Concrete Resistivity Tester
Instruction Manual
www.mkckorea.com

Contents
1. Introduction.........................................................2
2. Measurement and it's principle......................3
3. Components of Resitest-400M kit....................5
4. Basic information on Resitest-400M................6
5. Preparation for use Resitest-400M...................8
6. How to maintain Resitest-400M......................10
7. Operation of Resitest-400M.............................11
8. Inspection using Resitest-400M.......................13
9. Operation according to each mode............14
10. Analysis of results..............................................24
11. Maintenance......................................................25
12. Specifications.....................................................26
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1. Introduction
We thank you for your procurement of the Resitest-400M. Before using this
instrument, We recommend you are to be fully aware of this instruction
manual of the Resitest-400M. The Resitest-400M is a useful measuring
equipment that can be used to measure the electrical resistivity of the surface
of the concrete and detect corrosion state of reinforced concrete structures.
The Resitest-400M mainly consists of the basic equipment and the Wenner
array sensor. The measurement is to assess results when the Wenner sensor
contacts the surface of reinforced concrete structures.
In LCD battery status is displayed. It has "HOLD" key to hold present
measurement display and other keys to store measurement display in memory
Especially RT-400M has contour mapping function which enables easy analysis
of concrete status in site by color mapping.
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Note: If Wenner sensor comes into contact with statically charged
materials or high conductive materials such as metal as not
concrete or standard block, the electronic circuitry in Resitest-400M
will be damaged due to overflowing current.
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2. Measurement and it's principle
Corrosion of reinforcing steel is encountered in a variety of reinforced
concrete structures. Corrosion can result in spalling of the concrete and
reduction in the cross section of the reinforcement, thus it is important to
detect corrosion at an early stage of its development. The Half-cell potential
technique (Half-cell 200/Q-see man int'l) can be used to locate corroding
reinforcement without disrupting the concrete over to the reinforcing steel. By
adopting this technique, this is effective in locating regions of corrosion
activity using contour mapping program. However, to connect between the
electrical connection and reinforcement, a part of the concrete should be
disrupted
However Resitest-400M which has the Wenner sensor comes into contact with
the concrete cover, it can easily measure the state of corrosion of the
concrete cover.
The resistivity of the concrete extremely does an important role about
advancing corrosion. When the resistivity of the concrete is low, it is assumed
that the probability of active and rapidly advancing corrosion is very high
than the one of higher resistivity.
The resistivity is calculated using the formulae R=v/I and ρ=2πaR
where 'R' is the resistance, 'v' is the voltage measured across the
voltage electrodes, 'I' is the current flowing between the current
electrodes, 'ρ' is the resistivity and 'a' is the distance between the
electrodes.
R= v/I , ρ=2πaR
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The measurement Principle of the Resitest-400M
The Wenner sensor of the Resitest-400M consists of a row of four electrodes. By
passing an electric current between the two outer current electrodes and by
measuring the resultant voltage developed across the two liner 'voltage'
electrodes, the Resitest-400M is to assess the results and display the electrical
resistivity (㏀/㎝) on LCD of the main body.
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main body Wenner sensor Reference PCB Water container
Connection cable Insert sponge Sensor cap RT-4040 CD
Pouch Adaptor manual Carrying Bag
3. Components of Resitest-400MM
The Resitest-400M consists of the followings:
Resitest-400M main body
Wenner sensor
Reference PCB
Water container
Connection cable
Insert sponge (8)
Sensor cap (6)
RT-4040 CD concrete corrosion analysis & report program
Carrying Pouch
Instruction Manual
Aluminum carrying bag
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4. Basic information on Resitest-400M
From a long time ago, an inspection instrument which has the four point
electrodes had been used to measure and assess in soil strata. When the
Wenner sensor with four electrodes was used to measure the
corrosion of the concrete, several problems had been found. To solve
these problems, papers have been released in the early of 1980's. The
Colebrand Ltd. in England has developed the Resistivity logger on the
basis of "measurement of the Electrical Resistivity of Reinforced Concrete
Structures for the assessment of Corrosion Risk by S.G. Millard, J.A. Harrison &
A. J. Edwards) The CNS Ltd. in England also has developed the Resistivity
meter on the basis of "Resistivity Measurements in Concrete" by A.J. Ewins,
and Proceq SA in Switzerland has developed the Resi as a new Resistivity
meter lately.
The Resitest-400M was designed to make accurate measurements with
easy operation by solving the problems and inconveniences of the
existing equipments.
Even though the measurement of corrosion of the concrete using the
Resitest-400M is very effective, there are a few difficulties that must be
overcome to obtain reliable results, owing to the character of the concrete.
Because the concrete is an electrically non-homogeneous material, it is
likely to be affected by the ambient temperature and the moisture
content of the concrete. Measuring the same point by the Resitest-400M, the
accuracy of the result should be within ± 1%.
However, it must be remembered that the resistivity of the concrete
can vary as the moisture content changes. Values of less than 1㏀.cm for
water-saturated concrete can increase to over 100㏀.cm for the same
concrete when oven-dried.
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Therefore, be sure that the electrical resistivity of the concrete is
affected by the ambient temperature and the moisture content
change. Also an electrical current is affected by the reinforcement bar in the
concrete. Therefore, if the measurement is to be conducted on the area of
concrete with reinforcement bar, use the Covermeter-3000 (Q-see man int'l) or
other concrete cover meters to locate precisely the position of the reinforcing
bars. Thereafter, keep the Wenner sensor as far as possible from reinforcement
bars.
When the surface of the concrete is more narrower than the widthof the
Wenner sensor (150 mm) or when all of the four electrodes could not contact
with the surface of the concrete that is too rough, the measurements are
impossible. The Resitest-400M consists of a row of electrodes arranged at 50
mm spacing in a straight line. If the spacing is too small, the presence or
absence of the individual aggregate particles, usually having a very high
resistivity, will lead to high degree of scatter in the measurements. Using
larger spacing may lead to inaccuracies due to the current field being
constricted by the spacing will also increase the error in the measurement of
the concrete resistivity due to the increased influence of the conductive
reinforcing steel embedded below the surface of the concrete. Therefore, in
case that the surface of the concrete is more smaller the 150 mm, the
measurements could be impossible. In case that the surface of the
concrete is crooked or hollow, the measurement could be impossible as
well. Because the Wenner sensor is paralleled, all of the four electrodes
should be contacted on the surface of the concrete.
The results may be affected by the contact condition between the
electrodes and the concrete surface of the concrete.
In case Resitest-400M, it is easy to get the most accurate results using
special ring, should always pay attention to the contact condition.
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5. Preparation for use of Resitest-400M
a. How to insert the sponge into the Wenner sensor.
The sponge of the Wenner sensor should always be kept clean
condition to get accurate results. Before and after every
measurement, the sponge need to be cleaned, using Bath Tub
(water container), which is supplied with the instrument during
measurement.
Soak the sponges in water and insert them to the rings. After use,
take out the sponges to wash in tap water or clean water.
From time to time you should wash them, using bath tub.
b. How to connect the Wenner sensor to the main body.
After connecting the cable to the sensor, connect the cable to
the socket in the main body. If the main body is turned before
connecting the cable to the main body, the main body may be
damaged during connecting the cable so that it is advisable to turn
the instrument after connecting cables.
c. Concrete Surface
If the concrete surface is dry or wet, this can cause significant error.
Also when the concrete surface is stained, it can not be measured
and may cause significant error. If possible, therefore, it is advisable
to keep the concrete surface as the best condition. In case of the
concrete surface coated with oil paint, it is impossible to measure
the electrical resistivity. Likewise in the event of the concrete
surface coated with water paint, measurement may be incorrect.
Should be drilled 2 - 3 mm hole into the concrete in order to get
the best results.
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d. Main body
The Resitest-400M consumes the battery quite much so that you
would better take the instruments with full charged.
Before going on site, turn on the instrument and check whether
the instrument is operated well. Check if the measurement is O.K
with reference block.
While there is no pre-defined minimum spacing between
measurements on the surface of the concrete member, it is of little
value to take two measurements from virtually the same point,
Conversely, measurements taken with very wide spacing may
neither detect corrosion activity that is present nor result in the
appropriate accumulation of data for evaluation. The spacing shall
therefore be consistent with the member being investigated and
the intended end use of the measurements. Generally, a spacing of
50 cm has been used on site. But in case of the place where the
probability of corrosion is high, smaller spacing is recommended.
When measuring at a certain place, it is better to keep the Wenner
sensor as far as possible from the reinforced bars.
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6. How to maintain Resitest-400M
a. How to maintain the Resitest-400M.
If possible, it is advisable for the Resitest-400M to be kept in AL
carrying case. By doing so, the Resitest-400M is prevented from
moisture and dust. And in case of dropping that were caused by
mistake, damage can be minimized as well. The Resitest-400M can
be continuously used for about 5 hours. This is why before using it,
the battery should always be recharged.
b. How to maintain the Wenner sensor.
In the event of the measurement of the electrical resistivity of
concrete structures for the assessment of corrosion risk, 4 electrode
Wenner sensor is used on all occasions so far. Because the
accuracy of the instrument is affected by the contact condition
between the sponge and the concrete surface, the sponge
condition should be all the time. When the measurement is finished,
after pulling out the sponges and get rid of the moisture and then
keep them dry. The part of the Wenner sensor which is
made of the metal should be got rid of the moisture and kept from
rust. If the sponge is worn away, should be changed as new one.
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7. Operation of Resitest-400M
① MENU (MODE: pressing for a second or longer)
MENU: Select MENU. In MENU mode, stored data is called or erased and it
is possible to set up time.
MODE: Measurement mode is selected. Resitest-400M has normal
measurement mode and mapping mode. To change the mode, it
should be pressed for a second long.
② HOLD/SELECT (RANGE: pressing for a second or longer)
HOLD: used the measurement to be hold. Then signal lines of probe
icon on the upper left are stopped and HOLD icon is displayed.
By pressing again, get back to measurement mode.
SELECT: It is used in MENU mode to enter into selected MENU or enter
into set up.
RANGE: Used to select measurement range. To change measurement
range, press this key for a second or longer. There are 3
measurement ranges, 0~20, 20~200, 200~2,000(kΩ). In case the
measurement is not within measurement range, “OUT OF RANGE" is
displayed in LCD.
③ SAVE
To save or store what is measured.
④ CANCEL
Get back to measurement mode or cancel set up.
⑤,⑥ ▲/▼
To select MENU or make a set up in MENU mode.
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⑦ POWER Switch
ON/OFF switch to power or not.
⑧ RS-232 connector
Used to transfer the stored data to PC.
3PIN SERIAL CABLE should be used which was supplied with the
instrument.
⑨ CHARGER socket
The socket is for rechargeable batteries inside.
The charger supplied with the instrument should be used.
How to recharge batteries: First connect the plug in the charger to
the socket⑨ in the instrument and plug the power plug to 220 or 110V
power. When the adaptor is connected, red and green LED are lighted.
When the batteries are fully charged, green LED is extinguished.
⑩ SENSOR connector
To connect Wenner sensor to the instrument. The point marked with
black dot is the upside.
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8. Inspection using Resitest-400M
1. Inserting the sponge into the Wenner sensor.
Insert all of the soaked four sponges into the holes of the sensor's
contact. Before inserting the sponges, wash them in tap water or
clean water. During surveying, if the sponge is dried, the sponge
should be soaked in water using bath tub.
2. Connecting the Wenner Sensor to the main body.
After connecting the cable to the Wenner sensor, connect it to
the socket of the main body.
3. Turning on the Resitest-400M.
Power on, using the power key. At that time the Resitest-400M
should be displayed 000 or 001.
4. Confirming the Resitest-400M using the reference block.
When the Wenner sensor of RT-400M is contacted on the reference
confirm if it displays in the range of 62.5㏀.cm ±1.5 or not.
The displayed value in Resitest-400M should be within the range of
61.0 - 64.0㏀.㎝
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9. Operation according to each mode
1. Normal Measurement Mode
In normal measurement mode, traditional
measurement is performed. After measurements,
Max value, minimum value, number of stored
data are displayed.
How to store data measured
a. Contact Wenner sensor on concrete and
ascertain the measurement.
b. Press HOLD key to hold measurement.
c. After ascertaining if the measured value is
correct, press SAVE key and then SELECT key to
store the measurement. When CANCEL key is
pressed, the measurement is not stored and
returns to normal measurement mode.
d. When a datum was stored, SAVE COUNT: 1 is
displayed on the bottom of LCD.
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How to call stored data
a. Press MENU key to open MENU window.
b. Select “LOAD DATA” by pressing ▲/▼ key and
press SELECT key.
c. Data numbers, date and measurement value are
displayed one after one.
How to delete stored DATA
a. Press MENU key to open window.
b. By pressing ▲/▼ key, select “ALL DATA CLEAR”
and press SELECT key.
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c. If press SELECT key when “warning!" message
appears, all dat stored are deleted.
d. It can be ascertained by opening
LOAD DATA window.
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How to set up time
a. Open MENU window by pressing MENU key.
b. Press ▲/▼ keys to select “TIME SET” and press
SELECT key.
c. Press SELECT key in "CURRENT TIME" to change the
year.
d. Press ▲/▼ keys to set the year and then press
SELECT to select the month which is changed in
red color. Press ▲/▼ keys to set the month and
press SELECT key. The others are set up in same
manner.
e. When set up is completed, press CANCEL key to
close CURRENT TIME window.
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2. Mapping Mode
In MAPPING mode, the operator can edit any
co-ordinates and store measurement values
in the co-ordinates and finally generate
contour mapping image.
How to set any X,Y co-ordinates FORMAT
a. Press MENU to open MENU window.
b. Press ▲/▼ key to select “NEW FORMAT” and
press SELECT key.
c. When "WARNING!" message appears, press
SELECT key. At this point, not stored data are
deleted.
d. After input x, y co-ordinates values
in NEW FORMAT window, press SELECT.
(The co-ordinate values are set up by 2 x 2
through 10 x 10.)
e. After set up, press CANCEL key to return to
measurement mode.
\
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How to store measurement values in the FORMAT
a. After set up, contact the Wenner sensor on the
concrete surface and ascertain the
measurement.
b. Press HOLD key to hold the measurement value.
c. Press SAVE key to ascertain the measurement
value in MENU window, After ascertaining if the
value is correct, press SELECT key to store the
measurement. When CANCEL key is pressed, the
measurement is not stored and return to
measurement mode.
d. Contact Wenner sensor on the second point.
After ascertaining the measurement, repeat the
b-c procedure to store the data.
e. When all the blue colored cursors are gone and
all the measurement points are stored, then
mapping procedure is completed.
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