ISO 1920-6:2004 pdf free download.Testing of concrete Part 6 : Sampling , preparing and testing of concrete cores.
This part of ISO 1920 specifies a method for taking cores from hardened concrete, their examination, preparation for testing and determination of compressive strength.
The part of ISO 1920 does not give guidance on the decision to drill cores or on the locations for drilling nor does it provide procedures for interpreting the core strength results.
NOTE It is recommended that before coring, full agreement should be reached by all parties on the need for core testing and how the results should be Interpreted.
2 Normative references
The following referenced documents are essential for the application of this part of ISO 1920. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1920-4. Testing of concrete — Part 4: Strength of hardened concrete
ISO 1920-5, Testing of concrete — Part 5: Properties of hardened concrete other than strength
EN 12390-4:2000, Testing hardened concrete — Part 4: Compressive strength — Specification for testing
machines
3 Definitions
For the purposes of this document, the following definition applies.
3.1
core strength
compressive strength of the cored specimen, as determined by the test defined in this part of ISO 1920
4 Apparatus
NOTE Concrete compression testrg machines conforming Ic EN 12390-4 mIght need adaptation in order to lest cores small., Ih*n 90 mm diameter for oonteseon
4.3 Balance or scale, capable of detemwiing the mass of the core. as tested, to within en accuracy of
0,1 %o(the mass.
4.4 Callipers endior rules, capable of measuring the dimensions of the core end the steel reinforcement to a tolrance of ±1 %.
4.5 Gauge. capable of establishing that the relevant flatness of the specwien is within the requirements of clause 7.
4.6 Square. and gauges, capable of establishing that the perpendlciiarity and parallelism of speci1ems and moulds are wlthrn the requirements of Clause 7
5 Taking of cores
5.1 Location
Poesile structural implications resulting from taking a core shall be considered prior to driling and the location where the cores are to be taken specified.
Cores should preferably be taken at points not near to joints or edges of the concrete element to avoid as far as possible any reinforcement.
5.2 DrIlling
Unless otherwise specified, the cores shall be drilled perpendici4ar to the surface in such a manner as not to damage the cores. The drill frame shall be rigidly pos4ioned during corrig. Water shall be applied as a cooling fluid to the cutting edge of the core &III.
5.3 DIameter of cores
The diameter of the cores to be taken shall be specified.
The ratio of diameter to the maximum aggregate size should generally be greater than 3. The core diameter should generally be 100 mm 10mm ci 125mm t 10 mm or 150 mm ± 10mm, with the preferred diameter being 100 mm.
Other smaller diameters, which will make d.lllmg easier and reduce the damage to the element, may be used. provided the effect this has on the accuracy of the result is taken into account.
5.4 Length of cores
The length of core to be taken and the length the core has to be cut to shall be specified. In deciding the length of cores Ici strength testing, take the following into account:
a) the diameter of the core;
b) the possible method of adjustment
C) whether comparison will be made with cube strength or cylInder strength (see Clause 7 for preferred dierneterdlength ratios).
5.5 Marking and identification
Immediately after dn4ing. mark each core dearly and indelibly. Record its location and orientation witlin the element from which 4 was drilled. IF a core Is subsequently cut to produce a number of specimens. mark each apecireen to indicate its position and orientation within the original core.
5.6 Reinforcement
DrlIImg through reinforcement shall be avoided Cores containing any reinforcing bars In or close to the direction of the longitudinal ax’s shall not be used for strength testing.
6 Examination
6.1 Visual Inspection
Carry out visual examination of the cored specimen to identity abnormalities,
6.2 Measurements and calculations Take the followvig measurements:
a) core dlemeter Take pairs of measurements at flght angles, at the halt and quarter points of the length of the core to an accuracy oft 1 %. Determine the average diameter (m)•
b) core length: Measure the maximum and minimum lengths after completion of the end preparation
in accordance with Clause 7 (excluding capping material) to an accuracy of ± 1 %.
Determine the average length
c) mass: Where specified, each specimen shal be weighed as received and/or saturated. The
mass shall be recorded to the nearest 0.1 % of the mass of the specimen.
d) density: Where specified, the density of each specimen shall be determined as received and/or
saturated In accordance with ISO 1920-5 and the result recorded to the nearest
10 kg/rn3.
e) reinforcement: Measure the diameter (size) of any reinforcement. and the position of the reinforcement measured from the centre of the exposed bar to the end and/or axis of the core both as received and after end preparation. The measurements shall be to the nearest 1 mm.
All measurements shall be recorded.
7 Preparation of cores
7.1 General
The ends of cores for compression tests shall be prepared in accordance with Annex B of ISO 1920-42004.
NOTE Th. preferred method of preperwig the ends of cores by grinding.
7.2 Lengthidiarneter ratios
The preferred length/diameter ratios are as follows:
a) if the strength result is to be compared to cylinder strength. 2.0 i 5 %;
b) Wthestrengthreeullistobeoomparedtocubeslrength, 1,0±5%.
In the case of using a specimen with a length-to-diameter ratio smaller than 2,0. it is permissible to convert, by an appropriate method, the test value of the compressâve strength corresponding to a value for a length-todiameter ratio of 2,0.
7.3 Tolerances
Prepare the specwnen to within the following tolerances:
a) flatness: The tolerance on flatness of the prepared end surfaces shall be * 0.000 3dm. where
Is the average core diameter.
b) perpendicularity: The tolerance on perpendaculanty of the prepared end, with respect to the aias of the specimen as datum, abel be ± 0.5 rne.
c) paralletism: The tolerance on parallelism of the prepared top surface, with respect to the bottom
surface of the specimen as datum, shall be ± 1,0 mm.
d) straightness: The tolerance on straightness of any surface parallel to the centre line of the core
shall be ±3 % of the average core diameter (dm).
If cores with diameters less than the values recommended in 5.3, the tolerances above should be considered with regard to their adequacy and narrowed If necessary, for example, reduced In proportion to the actual specimen diameter of 100 mm.
8 CompressIon test
8.1 Storage
Record the storage condition(s) of the specimen.
If it is required to test the specimen in the saturated condition, soak in water at 20C ±2 C for at least 40 h before testing,
If it Is required to test the specimen in air-dry conditions, store in laboratory air for at least 40 h prior to testing. record the storage time, ambient temperature and relative humidity of the storage conditions during air-dry storage of the specimens.
8.2 Testing
Carry out the testing in accordance with ISO 1920-4 using a calibrated compression-testIng machme. Do not test cores with cracked, hollow or loose caps. frll the ,neasunng apparatus shall be in calibration at the time of the test.
Remove any loose sand or other material on the surface of the specimen.
If the specimen is to be tested whdst it is still wet, remove any surface waler.
Record the surface mosture condition (wet/dry) of the specimen at the time of teat.
9 Test results
Determine the con pressive strength of eacti specimen by dividing the maximum load by the cross-sectional area. calculated from the average diameter and express the restits to the nearest 0.5 MPa.
10 Test report
The report shall wiclude:
a) description and identification 01 the test specimen:
b) dale and time of test:
C) characterization of test specimen (if supplied): cement content and waterloement ratio. maximal nominal siz. of aggregate, type of admixture, date of casting, dale of taking core samples. etc.:
d) condition of test specimen on receipt: average diameter. Ml millimetres, maximum length, in milbmelres. minmum length. i millimetres, mass in alr. m grams (It appropriate), mass In water. in grams, (if appropriate), density. in kilograms per cubic metre (if appropriate):
e) visual Inspection riohog any abnormalities identifIed.
1) reinforcement (wt’len appropriate): diameter(s), ii millimetres, position4s). in millimetres:
9) method used for the preparation of specimen: nggnnd.ngicappwlg:
h) dimensions of prepared specimen: average length, ii milimetres, average diameter, in millimetres. iengthidlameler ratio.
I) storage: on receipt, prior to end preparation, after end preparation:
j) surface moisture condition at time of test:
k) test result: maximum load, in newtons or kilonewtons average area, in square millimetres. core compressive strength, In megapascals:
I) any deviations from the standard method of examination or compression testing;
m) a declaration by the person responsdle for the examination and testing that these were done In accordance with ISO 1920-62004 except as detailed in 101).