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Test methods and standard practices for concrete
3 Definition
In addition to the definitions specified in CSA A23.1, the following definition applies in this Test Method:
Constant mass — the condition of a test sample dried at a temperature of 110 °C ± 5 °C such that the
sample will not lose more than 0.1% moisture after 2 h of drying.
Note: Such a condition of dryness can be verified by determining the mass of the sample before and after successive 2 h
drying periods. In lieu of such a determination, samples may be considered to have reached constant mass when they have
been dried at a temperature of 110 °C ± 5 °C for an equal or longer period than that previously found adequate for
producing the desired constant mass condition under equal or heavier loading conditions of the oven.
4 Significance and use
Water soluble chloride, when present in sufficient amount, is capable of leading to the initiation or
acceleration of corrosion of ferrous metals, embedded in or contacting a cement based mortar, grout, or
concrete. Determination of the chloride ion content or profile with depth may form part of an
investigation to determine the cause of corrosion and/or potential for future corrosion. However, it must
be recognized that water soluble chloride determined at some particular time in the life of a concrete
element can be substantially different than at another time.
Clause 4.1.1.2 of CSA A23.1 provides limits on chloride ion content.
5 Apparatus
5.1 Sampling
The apparatus for sampling shall include the following:
(a) a rotary-impact-type drill with pulverizing bits of sufficient diameter to provide a representative
sample of sufficient size for testing or a concrete coring drill with a bit of sufficient size to provide a
concrete core, which can be sliced by saw cutting, to represent a range of depths from the concrete
surface (the volume of the slices to be sufficient to produce samples suitable for pulverizing). In the
latter instance, provide a suitably sized cut off saw fitted with a diamond segmented saw blade.
(b) a spoon or other suitable means to remove pulverized sample material from the drill hole without
contamination;
(c) a syringe or other suitable means to clean any remaining material from the drill hole without
contamination; and
(d) sample containers capable of maintaining samples in an uncontaminated state.
5.2 Testing
The apparatus for testing shall include the following:
(a) silver, chloride/sulphide ion selective electrode or a silver billet electrode coated with silver chloride
with an appropriate reference electrode;
Note: Suitable electrodes are available from Orion, Beckman Instruments, Fisher Scientific, and Leeds and Northrup.
The manufacturer’s instructions should be followed.
(b) a potentiometer with a millivolt scale readable to 1 mV or better. A digital readout is preferred, but
not required;
(c) a buret, Class A, 10 mL capacity with 0.05 mL divisions. A buret of the potentiometric type with a
displaced delivery tip is convenient, but not required;
(d) a magnetic stirrer and TFE fluorocarbon-coated stirring bar;
(e) a hotplate;
(f) disposable weighing boats;
(g) 315 μm and 160 μm sieves;
(h) an agate mortar and pestle;
(i) various glassware, consisting of 250 mL beakers, filter funnels, stirring rods, watch glasses, droppers,
and wash bottles;
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(j) Whatman Nos. 40 and 41 filter paper or equivalent; and
(k) a balance sensitive to 100 μg with a minimum capacity of 100 g.
6 Hazards
This Test Method does not purport to include all safety issues associated with its use. It is the responsibility
of the user to establish appropriate safety and health practices.
7 Reagents
The following reagents shall be used for testing:
(a) sodium chloride (NaCl), primary standard grade;
(b) silver nitrate (AgNO3), reagent grade;
(c) potassium chloride (KCl), reagent grade (required for silver billet electrode only);
(d) reagent water conforming to the requirements of ASTM D1193 for Type III reagent water; and
(e) ethyl alcohol, technical grade.
8 Preparation of solutions
The solutions shall be prepared as follows:
8.1
(a) For sodium chloride, standard solution (0.05 N NaCl):
(a) Dry sodium chloride (NaCl) at 110 °C ± 5 °C to a constant mass;
(b) Measure 2.922 g of dried reagent; and
(c) Dissolve in water and dilute to exactly 1 L in a volumetric flask and mix thoroughly.
This solution is the standard and requires no further standardization.
8.2
For silver nitrate, standard solution (0.05 N AgNO3):
(a) Dissolve 8.494 g of silver nitrate (AgNO3) in water;
(b) Dilute to 1 L in a volumetric flask and mix thoroughly;
(c) Standardize against 5.00 mL of standard 0.05 N sodium chloride solution diluted to 150 mL with
water following the titration method given in Clause 10.7 beginning with the second sentence; and
(d) Calculate the exact normality from the average of three determinations, as follows:
N=
0.25
V
where
N
= normality of AgNO3 solution
0.25 = milliequivalents NaCl (5.0 mL × 0.05 N)
V
= volume of AgNO3 solution, mL
8.3
For methyl orange indicator, prepare a solution containing 2 g of methyl orange per litre of 95% ethyl
alcohol.
Note: Commercially available standard solutions may be used provided that the normality is verified according to the
standardization procedure.
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Test methods and standard practices for concrete
9 Sampling
9.1 Sampling method from test sample
9.1.1
Cast grout columns (or 50 mm cubes) or, in the case of concrete, test cylinders, directly from the mix to
be tested in accordance with the applicable requirements of CSA A23.2-1B or CSA A23.2-3C, respectively.
Seal specimens immediately after casting and consolidation and allow to cure for a minimum 28 d period
before sampling.
Note: The 28 d curing period is required to minimize the variations in water-soluble chloride that may occur with
insufficiently cured specimens.
9.1.2
Using the rotary impact drill, drill parallel to the axis of the specimen to a depth sufficient to obtain a
representative sample of at least 30 g of pulverized material finer than a 315 μm sieve or saw-cut a slice of
concrete of sufficient volume to produce a sample of at least 30 g after pulverizing the material finer than
a 315 μm sieve.
Note: To prevent sample contamination, contact between the sample and hands should be avoided. All sampling tools
should be cleaned with ethyl alcohol and dried prior to each sampling operation. No lubricants should be used during drilling
or sawing.
9.1.3
Transfer the pulverized sample into sample container using a spoon or other suitable means.
9.2 Sampling method from structures
9.2.1
The sample may be obtained using a rotary impact drill perpendicular to the surface of the concrete under
test.
When the sample represents a certain depth of concrete, remove the concrete above this layer and
clean the area of any residue to prevent contamination of the subsequent layers.
Note: Several holes from the impact drill can be required to avoid the influence of coarse aggregate particles and to obtain
a representative sample of at least 30 g of pulverized material.
9.2.2
An alternative method is to drill a sufficiently large core, suitable for slicing by saw-cutting to represent a
range of depths from the concrete surface. Pulverize each concrete slice to obtain a representative sample
of at least 30 g of material finer than a 315 μm sieve.
Notes:
(1) Water used to cool drill bits and saw blades may dissolve some of the chloride in the concrete. Air or light oil cooling is
preferred.
(2) Concrete cores may be cut laterally into 10 mm thick disks representative of the concrete core at various depths, or cut
longitudinally to provide a 10 mm thick section generally representative of the core.
9.3 Sample preparation
9.3.1
Dry the pulverized samples to constant mass at 110 °C ± 5 °C.
9.3.2
If the sample, as collected, does not completely pass a 315 μm sieve, perform additional pulverizing with a
mortar and pestle until the entire sample is finer than 315 μm.
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10 Test procedure
10.1
Measure a representative 3 g sample in a disposable weighing boat. Transfer the sample to a mortar and
add 10 mL of hot water. Grind the slurry with a pestle until all lumps are eliminated and the resulting
particles will pass a 160 μm screen.
Note: About 75% of a properly ground sample will pass a 80 μm screen. The analyst should grind several trial samples in
accordance with the above procedure and then dry the samples and determine the particle size as a means of defining the
grinding required for actual samples.
10.2
Transfer the slurry from the mortar through a funnel into a 250 mL beaker. Rinse the mortar and pestle
with hot water. Finally, wash the funnel with hot water and make up the volume to 75 mL.
10.3
Cover with a watch glass and boil for 5 minutes. Then let stand for 24 h from the end of the boil in an
atmosphere free of HCl fumes.
Note: It is important to keep the beaker covered during heating and digestion to prevent the loss of chloride by
volatilization.
10.4
Fit a 250 mL or 500 mL Buchner funnel and filtration flask with a 9 cm double filter paper consisting of a
Whatman No. 41 over a No. 40. Wash the papers with nitric acid before water washing to prevent
contamination of the sample. Wash the filter papers with four 25 mL increments of water using suction
filtering. Discard the washings and rinse the flask once with a small portion of water. Reassemble the
suction apparatus and filter the sample solution. Rinse the beaker and the filter paper twice with small
portions of water. Transfer the filtrate from the flask to a clean 250 mL beaker and rinse the flask once with
water. Ensure that the volume does not exceed 175 mL.
10.5
Add three drops of methyl orange indicator to the sample solution and then add HNO3 dropwise until a
permanent pink to red colour is obtained. Make up the volume to 200 mL with water.
10.6
For instruments equipped with dial readout, establish an approximate “equivalence point” by immersing
the electrodes in a beaker of water and adjusting the instrument to read about 20 mV lower than
midscale. Record the approximate millivoltmeter reading. Remove the beaker and wipe the electrodes
with absorbent paper.
10.7
To the sample beaker specified in Clause 10.4, carefully pipette 2 mL of standard 0.05 N NaCl solution.
Place the beaker on a magnetic stirrer and add a TFE fluorocarbon-coated magnetic stirring bar. Immerse
the electrodes in the solution, taking care that the stirring bar does not strike the electrodes; begin stirring
gently. Place the delivery tip of the 10 mL buret, filled to the mark with standard 0.05 N silver nitrate
solution, in (preferably) or above the solution.
Notes:
(1) A constant temperature should be maintained during measurement because the solubility relationship of silver chloride
varies markedly with temperature at low concentrations.
(2) If the tip of the buret is out of the solution, any adhering droplet should be rinsed onto the beaker with a few millilitres
of water following each titration increment.
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Test methods and standard practices for concrete
10.8
Gradually titrate and record the amount of standard 0.05 N silver nitrate solution required to bring the
millivoltmeter reading to –60.0 mV of the equivalence point determined in the water.
10.9
Continue the titration at 0.20 mL increments. Record the buret reading and the corresponding
millivoltmeter reading in columns 1 and 2 of a four-column recording form as shown in Attachment A1.
Allow sufficient time between each addition for the electrodes to reach equilibrium with the sample
solution. Experience has shown that acceptable readings are obtained when the minimum scale reading
does not change within a 5 second period (usually within 2 minutes).
10.10
As the equivalence point is approached, the equal additions of AgNO3 solution will cause larger and larger
changes in the millivoltmeter readings. Past the equivalence point, the change per increment will again
decrease. Continue to titrate until three readings past the approximate equivalence point have been
recorded.
10.11
Calculate the difference in millivolt readings between successive additions of titrant and enter the values in
column 3 of the recording form. Calculate the difference between consecutive values in column 3 and
enter the results in column 4. The equivalence point of the titration will be within the maximum ∆mV
interval recorded in column 3. The precise equivalence point can be interpolated from the data listed in
column 4 as shown in Attachment A1.
10.12
Make a blank determination using 75 mL of water in place of the sample, following the procedure outlined
in Clauses 10.5 to 10.11. Correct the results obtained in the analysis accordingly by subtracting the blank.
Note: If the sample is not a referred analysis, then the blank may be omitted. In such cases, calculate the chloride
percentage in the sample, as follows:
Cl, % = 3.5453 (VN – 0.10)/M
where
V
N
0.10
M
=
=
=
=
0.05 N AgNO3 solution used for sample titration (equivalence point), mL
exact normality of 0.05 N AgNO3 solution
milliequivalents of NaCl added (52 mL; 0.05 N)
mass of sample, g
11 Calculations
The chloride percentage shall be calculated to the nearest 0.001% (10 mg/kg), as follows:
Cl, % =
3.545VN
M
where
V
= 0.05 N AgNO3 solution used for titration of the sample (equivalence point), mL
N
= exact normality of 0.05 N AgNO3 solution
M = mass of sample, g
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12 Reporting
12.1 Required information
The following information shall be included in the test report:
(a) identification of the certified laboratory performing the test (i.e., name and address);
(b) sample number or identification marks;
(c) test age of laboratory cast samples;
(d) water-soluble chloride ion content expressed as a percentage of the concrete or grout mass to the
nearest 0.001%;
(e) name and signature of the person responsible for the review of the test report;
(f) any deviations from the test procedure; and
(g) optional Information.
12.2 Optional information
The following information may be included in the test report:
(a) name of technician who obtained the sample;
(b) date sample was taken or received by the test laboratory;
(c) test age of field cast samples; and
(d) sample source or sample location, or both.
13 Precision and bias
13.1 Precision
The precision statement in this Clause is based on ASTM C1218, using data from more coarsely ground
samples (passing a 600 μm sieve rather than a 160 μm sieve).
The single laboratory standard deviation has been found to be 0.0013% chloride by mass of sample.
Therefore, results of two properly conducted tests by the same operator on the same coarse aggregate
should not differ from each other by more than 0.0037%. The multi-laboratory standard deviation has
been found to be 0.0037% chloride by mass of sample. Therefore, results of two properly conducted tests
from two laboratories on samples of the same material are not expected to differ from each other by more
than 0.0106%.
13.2 Bias
The procedure in this Test Method has no bias because the value of water soluble chloride is defined by
the procedure.
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Test methods and standard practices for concrete
Attachment A1 (informative)
Example of determination of equivalence point
for chloride determination
Note: This Attachment is not a mandatory part of this Test Method.
1
2
3
4
AgNO3, mL
Potential, mV
∆mV*
∆2mV†
1.60
125.3
—
5.8
1.80
119.5
1.4
7.2
2.00
112.3
1.3
8.5
2.20
103.8
1.3
9.8
2.40
94.0
0.6
9.2
2.60
84.8
2.3
6.9
2.80
77.9
0.8
6.1
3.00
71.8
1.3
4.8
3.20
67.0
—
*Differences between successive readings in column 2.
†Differences between successive ∆ readings in column 3 “second differentials”.
Note: The equivalence point is in the maximum ∆mV interval (column 3) and thus
between 2.20 mL and 2.40 mL. The exact equivalence point in this 0.20 increment is
calculated from the ∆2mV (column 4) data as follows:
E = 2.2 +
1.3
× 0.20 = 2.337 mL (round to 2.34 mL )
1.3 + 0.6
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A23.2-6B
Determination of bond strength of bonded
toppings and overlays and of direct tensile
strength of concrete, mortar, and grout
1 Scope
This Test Method specifies the procedure to determine the bond strength of bonded toppings and the
direct tensile strength of concrete, mortar, and grout by tensile load. It also applies to all other materials
bonded to concrete.
This Test Method outlines two procedures. Procedure A enables the determination in-situ and
Procedure B enables the determination in the laboratory of the bond and direct tensile strength of
cementitious materials.
2 Reference publications
In addition to the references in CSA A23.1, this Test Method refers to the following publications, and
where such reference is made, it shall be to the editions listed below, including all amendments published
thereto:
CSA Group
A23.1-14
Concrete materials and methods of concrete construction
A23.2-3C-14
Making and curing concrete compression and flexural test specimens
A23.2-12C-14
Making, curing, and testing compression test specimens of no-slump concrete
A23.2-14C-14
Obtaining and testing drilled cores for compressive strength testing
ASTM International (American Society for Testing and Materials)
E4-13
Standard Practices for Force Verification of Testing Machines
3 Summary of test method
In this Test Method, the surface or the two ends of the specimen are gripped or bonded to the machine
device and a tensile force is applied to cause rupture. Bond or tensile strength is obtained by dividing the
maximum applied load by the cross-sectional area of the specimen.
4 Significance and use
Procedures A and B are used to determine the tensile strength of cylindrical specimens prepared and cured
in accordance with CSA A23.2-3C, CSA A23.2-12C, and CSA A23.2-14C.
In addition to providing information on bond strength, this Test Method can also be used to determine
the impact of microcracking in concrete affected by alkali-aggregate reaction or fatigue. The location of
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Test methods and standard practices for concrete
failure is determined visually and gives an indication regarding the element in the tested system having
the lowest tensile strength properties.
5 Apparatus
5.1 Procedure A
5.1.1 Pullout and load measuring device
The pullout and load measuring equipment shall consist of a mechanical or hydraulic pullout device
coupled to a calibrated load cell, bourdon tube gauge, or a dynamometer. The counter pressure ring of
the pullout device shall be designed to accommodate the fastening devices described in Clause 5.1.2.
Note: The mechanical testing apparatus of Figure 1 has been shown to be functional.
5.1.2 Fastening devices
The fastening devices shall consist of a rigid plate with pullout attachment or standard pipe caps; the
bottom of the plate or cap shall be machined smooth and shoulder-cut to provide a plane surface. The
outside diameter (D1) of the fastening device shall be slightly smaller than the inner diameter of the core
bit (D2). The connection between the pullout device and the fastening device shall ensure a tensile force
perpendicular to the bottom plane of the fastening device.
Note: A schematic diagram is presented in Figure 2.
5.1.3 Coring drill
A concrete coring drill with the inner diameter of the core bit slightly larger than the fastening device and
the outside diameter (D3) smaller than the counter pressure ring (D4) of the pullout device shall be used
to drill an annular ring through the layer under test and into the underlying concrete. The minimum
diameter of the core bit shall be 3 times the nominal maximum aggregate size but in no case less than
60 mm.
5.1.4 Bonding agent
A commercially available room temperature, rapid-curing epoxy compound adhesive having sufficient
tensile adhesive strength to satisfy the requirements of the test shall be used.
5.2 Procedure B
5.2.1 Load measuring device
The testing machine shall have sufficient capacity and capability to provide the rates of loading specified in
Clause 8.2.2.
The device shall be verified at suitable time intervals requirements specified in ASTM E4 and under the
following conditions:
(a) on original installation or relocation of the machine;
(b) after an elapsed interval since the previous verifications of 18 months maximum, but preferably after
an interval of 12 months.
5.2.2 Fastening devices
Any kind of grips or epoxy bonded caps that produce a uniform tensile strength in the middle third of the
specimens may be acceptable for use in this Test Method.
Note: Cylindrical or square metal caps of sufficient diameter or dimension, when bonded to the specimen ends provide, for
old concrete, a means through which the direct tensile load can be applied. It could be required to have a reduced section in
the middle third of the test specimens when the method is applied to the determination of tensile strength of new concrete.
Grips or caps shall be provided with a suitable linkage system for load transfer from the loading device
to the test specimen. The linkage system shall be designed so that the load will be transmitted through the
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axis of test specimens without the application of bending or stresses in torsion. The length of the linkages
at each end shall be at least two times the diameter of the metal and caps or grips.
Note: Roller of link chain of suitable capacity, appropriate universal joints to minimize eccentric loading, and
ball-and-socket of suitable dimension have been found to perform quite well in this application. Figure 3 shows a suitable
device.
6 Hazards
This Test Method does not purport to address the safety problems associated with its use. It is the
responsibility of the user of this Test Method to establish appropriate safety and health practices and
determine the applicability of regulatory limitations prior to use.
7 Sampling and test specimens
7.1
A minimum of two satisfactory tests shall be performed and each result will provide a test value.
The core specimens for the determination of tensile strength or adhesion shall have a diameter of at
least three times the nominal maximum size of the coarse aggregate used in any part of the bonded
system or in the cementitious material but in no case less than 50 mm.
Note: A minimum core diameter of 75 mm should be used whenever practical.
7.2
The test specimens for Procedure B shall be prepared in accordance with CSA A23.2-14C, except that the
degree of flatness and smoothness of the specimen’s end is not critical. End surfaces, such as those
resulting from sawing with a diamond cut-off wheel, may be acceptable. The ratio of length between grips
or caps to diameter of the specimen shall be, as nearly as practicable, between 0.75 and 1.0.
Note: A smaller ratio results in a greater variability in test results.
7.3
If required, a reduced section shall be obtained by kerfing. The cross-section shall be reduced all around by
a notch 10 mm deep in the middle third of the test specimen. The width of the notch should be between
10 mm and 15 mm.
Note: Grinding, lapping, or polishing beyond this point serves no useful purpose and, in fact, may adversely affect the
adhesion of bonding of medium caps.
8 Procedure
8.1 Procedure A
The overlay shall be cored to a minimum of 30 mm into the underlying concrete. The surface of the cored
disk shall be cleaned and the fastening device shall be bonded to the disk’s centre, using the epoxy
compound. The fastening device may be heated to facilitate spreading of the adhesive and to accelerate
its hardening as long as this does not modify the properties of the material tested.
When the adhesive has reached sufficient strength, the fastening device shall be attached and the
tensile load shall be applied at a rate of approximately 50 N/s to 100 N/s, making sure that the axis of the
loading device coincides with the axis of the fastening device. The load indicated on the measuring gauge
at failure shall be recorded. A minimum of three satisfactory tests shall be performed (see Clause 7) and
averaged to provide a test value.
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