1、 Reference number ISO 1920-4:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 1920-4 First edition 2005-07-15 Testing of concrete Part 4: Strength of hardened concrete Essais du bton Partie 4: Rsistance du bton durci ISO 1920-4:2005(E) PDF disclaimer This PDF file may contain embedded typefaces. In accord
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6、neva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2005 All rights reservedISO 1920-4:2005(E) ISO 2005 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Determination of compressive str
7、ength. 1 3.1 Test specimens . 1 3.2 Apparatus 2 3.3 Procedure 2 3.4 Test results 6 3.5 Test report . 6 4 Determination of flexural strength 6 4.1 Test specimens . 6 4.2 Apparatus 6 4.3 Procedures 8 4.4 Test results 9 4.5 Test report . 10 5 Determination of tensile splitting strength 10 5.1 Specimens
8、 . 10 5.2 Apparatus 10 5.3 Procedure 11 5.4 Test results 13 5.5 Test report . 13 6 Test report . 14 Annex A (normative) Precision data for measurements of compressive strength. 15 Annex B (normative) Adjustment of test specimens for the compressive strength test . 16 Annex C (informative) Examples o
9、f test reports . 25 ISO 1920-4:2005(E) iv ISO 2005 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO techni
10、cal committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely w
11、ith the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Int
12、ernational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document m
13、ay be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 1920-4 was prepared by Technical Committee ISO/TC 71, Concrete, reinforced concrete and pre-stressed concrete, Subcommittee SC 1, Test methods for concrete. This first edition of
14、ISO 1920-4:2005 cancels and replaces the first editions of ISO 4012:1978, ISO 4013:1978 and ISO 4108:1980, which have been technically revised. ISO 1920 consists of the following parts, under the general title Testing of concrete: Part 1: Sampling of fresh concrete Part 2: Properties of fresh concre
15、te 1) Part 3: Making and curing test specimens Part 4: Strength of hardened concrete Part 5: Properties of hardened concrete other than strength Part 6: Sampling, preparing and testing of concrete cores Part 7: Non-destructive tests on hardened concrete The following parts are under preparation: Par
16、t 8: Determination of drying shrinkage of concrete Part 9: Determination of creep of concrete This series of Draft International standards was based on existing and draft ISO standards and on draft CEN standards dealing with testing concrete. 1) To be published. INTERNATIONAL STANDARD ISO 1920-4:200
17、5(E) ISO 2005 All rights reserved 1 Testing of concrete Part 4: Strength of hardened concrete 1 Scope This part of ISO 1920 specifies procedures for testing the strength of hardened concrete. 2 Normative references The following referenced documents are essential for the application of this document
18、. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 48, Rubber, vulcanized or thermoplastic Determination of hardness (hardness between 10 IRHD and 100 IRHD) ISO 679, Methods of testing
19、cement Determination of strength ISO 1920-3, Testing of concrete Part 3: Making and curing test specimens ISO 2781, Rubber, vulcanized Determination of density ISO 3310-1, Test Sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth ISO 4662, Rubber Determination of rebound
20、 resilience of vulcanizates EN 316:1999, Wood Fiberboards Definition, Classification and Symbols EN 12390-4:2000, Testing Hardened Concrete Part 4: Compressive Strength Specification for Testing Machines 3 Determination of compressive strength 3.1 Test specimens The test specimen shall be a cube or
21、a cylinder meeting the requirements of ISO 1920-3 or cores meeting the requirements of ISO 1920-6. Damaged specimens shall not be tested. Specimens that are badly honeycombed shall not be regarded as being representative of the quality of concrete supplied. In general, standard cube and cylinder spe
22、cimens should not be tested if they are badly honeycombed as this is an indication of poor specimen making. When such specimens are tested, the test report shall include the fact that the specimen was honeycombed. ISO 1920-4:2005(E) 2 ISO 2005 All rights reservedWhere the designated size, l 1or l 2
23、, of the cross-section is outside the tolerances, the specimens may be used for testing by using the actual dimensions; see 3.4. Where the dimensions or shape of a test specimen exceed the respective tolerances given in ISO 1920-3, the specimen shall be rejected or adjusted (if feasible) by one or m
24、ore of the following methods: uneven surfaces levelled by grinding or by capping; the deviation of angles corrected by cutting and/or grinding. The procedures given in Annex B shall be used to adjust the specimen. Adjustment by grinding shall be the reference method. 3.2 Apparatus The test shall be
25、carried out using a compression-testing machine conforming to EN 12390-4 or to a national standard valid in the place of testing. The test machine shall be in calibration at the time of test. The calibration shall be carried out at least once per year. 3.3 Procedure 3.3.1 Preparation and positioning
26、 of specimens For specimens stored in water, excess moisture shall be wiped from the surface of the specimen before placing in the testing machine. The time between the extraction of the specimen from the humidity chamber or the water tank until the test shall be as short as possible and not more th
27、an 3 h. During the time the specimen is outside the humidity chamber or water tank, it shall be protected from drying, e.g. by covering with wet burlap. All testing-machine bearing surfaces shall be wiped clean and any loose grit or other extraneous material removed from the surfaces of the specimen
28、 that will be in contact with the platens. Do not use packing, other than auxiliary platens or spacing blocks, between the specimen and the platens of the testing machine. Cube specimens shall be compressed perpendicularly to the direction of casting. The specimen shall be centred on the lower plate
29、n to an accuracy of 1 % of the designated size of cubic, or diameter of cylindrical specimens. Where physical means of ensuring centring are provided on the testing machine and they are in calibration, these shall be deemed to satisfy the requirements for accuracy of centring. If auxiliary platens a
30、re used, the top auxiliary platen shall be aligned with the top of the specimen. With two-column testing machines, cubic specimens should be placed with the trowelled surface facing a column. 3.3.2 Loading The load shall be applied without shock and shall be increased continuously at a constant rate
31、 until no greater load can be sustained. Select a rate of stress not less than 0,15 MPa/s and not greater than 1,0 MPa/s. When using manually controlled testing machines, any tendency for the selected rate of loading to decrease as specimen failure is approached shall be corrected by appropriate adj
32、ustment of the controls. ISO 1920-4:2005(E) ISO 2005 All rights reserved 3 When using automatically controlled testing machines, the rate of loading whilst testing concrete specimens in compression shall be periodically checked to ensure that the rate is constant. The maximum load indicated shall be
33、 recorded. 3.3.3 Assessment of type of failure For cubic specimens, if the failure is satisfactory (see Figure 1), this fact shall be recorded. If the failure pattern is unsatisfactory, this fact shall be recorded and the type of failure recorded using the pattern number in Figure 2 closest to that
34、observed. For cylindrical specimens, if the failure is satisfactory (see Figure 3), this fact shall be recorded. If the failure pattern is unsatisfactory, this fact shall be recorded and the type of failure recorded using the pattern letter in Figure 4 closest to that observed. NOTE Unsatisfactory f
35、ailures can be caused by insufficient attention to the detailed procedures for making, capping and testing specimens or by a machine fault. NOTE 1 All four exposed faces are cracked approximately equally, generally with little damage to faces in contact with the platens. NOTE 2 Figure 1 c) demonstra
36、tes explosive failure. Figure 1 Satisfactory failures of cube specimens ISO 1920-4:2005(E) 4 ISO 2005 All rights reservedKey T indicates a tensile crack Figure 2 Some unsatisfactory failures due to unequal cracking of the exposed faces of cube specimens Figure 3 Satisfactory failure of cylinder spec
37、imen ISO 1920-4:2005(E) ISO 2005 All rights reserved 5Figure 4 Some unsatisfactory failures of cylinder specimens ISO 1920-4:2005(E) 6 ISO 2005 All rights reserved3.4 Test results The compressive strength is given by the equation: c c F f A = (1) where f cis the compressive strength, expressed in me
38、gapascals; F is the maximum load, expressed in newtons A cis the cross-sectional area, expressed in square millimetres, of the specimen on which the compressive force acts. If the actual dimensions of the test specimen are within 0,5 % of the designated size, the strength may be calculated on the ba
39、sis of the designated size. If the actual dimensions are outside this tolerance, the strength calculation shall be based on the actual dimensions of the test specimen, determined in accordance with ISO 1920-3. The compressive strength shall be expressed to the nearest 0,5 MPa. 3.5 Test report In add
40、ition to the requirements in Clause 6, the test report shall include the following: type of specimen: cube, cylinder or core; method of adjustment, if relevant; compressive strength of specimen (to the nearest 0,5 MPa); type of failure (satisfactory or unsatisfactory, and, if unsatisfactory, the nea
41、rest type). 4 Determination of flexural strength 4.1 Test specimens The test specimen shall be a prism conforming to ISO 1920-3. Sawn specimens of nominal width, l, of 100 mm or 150 mm with a square cross-section and overall length of between 4l and 5l may also be tested to this part of ISO 1920. Th
42、e ratio of l to the maximum size of aggregate shall be not less than four, except for specimens with a nominal width of 150 mm and a maximum size of aggregate of 40 mm, which may also be tested. The direction of casting shall be identified on the specimen. 4.2 Apparatus 4.2.1 Testing machine The tes
43、t shall be carried out using a testing machine conforming to EN 12390-4:2000, 4.2 and 4.3, or to a national standard valid in the place of testing. ISO 1920-4:2005(E) ISO 2005 All rights reserved 7 4.2.2 Force application The device for applying loads shall consist of two upper rollers and two lower
44、 rollers (see Figure 5). All rollers shall be manufactured from steel and shall have a circular cross-section with a diameter between 20 mm and 40 mm and shall be at least 10 mm longer than the width of the test specimen. Each roller, except one of the lower ones, shall be capable of rotating around
45、 its axis and of being inclined in a plane normal to the longitudinal axis of the test specimen. The distance, L rol , between the lower (outer) rollers (i.e. the span) shall be equal to 3l, where l is the width of the specimen. The distance between the upper (inner) rollers shall be equal to l. The
46、 inner rollers shall be equally spaced between the outer rollers as shown in Figure 5. All rollers shall be adjusted in the positions illustrated in Figure 5 to an accuracy of 2 mm. Key 1 loading roller (capable of rotation and of being inclined) 2 supporting roller 3 supporting roller (capable of r
47、otation and of being inclined) Figure 5 Arrangement for loading a test specimen (two-point loading) ISO 1920-4:2005(E) 8 ISO 2005 All rights reserved4.3 Procedures 4.3.1 Preparation and positioning of specimens The specimen shall be examined and any abnormalities shall be reported. For specimens sto
48、red in water, excess moisture shall be wiped from the surface of the specimen before placing in the testing machine. The time between the extraction of the specimen from the humidity chamber or the water tank until the test shall be as short as possible and not more than 3 h. During the time the spe
49、cimen is outside the humidity chamber or water tank, it shall be protected from drying, e.g. by covering with wet burlap. All testing-machine bearing surfaces shall be wiped clean and any loose grit or other extraneous material removed from the surfaces of the specimen that will be in contact with the rollers. The test specimen shall be placed in the machine, correctly centred with the longitudinal axis of the specimen at right angles to the longitudinal axis of the uppe
