ISO 1920-4:2020 pdf download

ISO 1920-4:2020 pdf download.Testing of concrete — Part 4: Strength of hardened concrete
1 Scope
This document specifies procedures for testing the strength of hardened concrete.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 48-2, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 2: Hardness between 10 IRHD and 100 IRHD
ISO 679, Cement — Test methods — Determination of strength
ISO 1920-3, Testing of concrete — Part 3: Making and curing test specimens
ISO 1920-6, Testing of concrete — Part 6: Sampling, preparing and testing of concrete cores
ISO 2781, Rubber, vulcanized or thermoplastic — Determination of density
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 4662, Rubber, vulcanized or thermoplastic — Determination of rebound resilience
EN 316, Wood fiberboards — Definition, classification and symbols
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Determination of compressive strength
4.1 Test specimens
The test specimen shall be:
— a cube or a cylinder in accordance with ISO 1920-3; or
— cores in accordance with ISO 1920-6.
Damaged specimens shall not be tested.
Specimens that are badly honeycombed and cracked shall not be regarded as being representative of the quality of concrete supplied. In general, standard cube and cylinder specimens 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. Where the designated size, l 1 or l 2 , of the cross-section is outside the tolerances, the specimens may be used for testing by using the actual dimensions; see 4.6. 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 more 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.
4.2.1 A compression-testing machine, robust, related to the size of specimen and capable of providing the rate of loading with minimum desired specifications as mentioned in 4.5.1 and 4.5.2. It shall be in calibration at the time of test. The calibration shall be carried out at least once per year.