ISO 20290-2:2019
(Main)Aggregates for concrete — Test methods for mechanical and physical properties — Part 2: Method for determination of resistance to fragmentation by Los Angeles Test (LA-Test)
Aggregates for concrete — Test methods for mechanical and physical properties — Part 2: Method for determination of resistance to fragmentation by Los Angeles Test (LA-Test)
This document describes the Los Angeles test, for determining the resistance to fragmentation of coarse aggregates.
Granulats pour béton — Méthodes d'essai relatives aux propriétés mécaniques et physiques — Partie 2: Partie 2: Méthode de détermination de la résistance à la fragmentation par l'essai Los Angeles
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 20290-2
First edition
2019-11
Aggregates for concrete — Test
methods for mechanical and physical
properties —
Part 2:
Method for determination of
resistance to fragmentation by Los
Angeles Test (LA-Test)
Granulats pour béton — Méthodes d'essai relatives aux propriétés
mécaniques et physiques —
Partie 2: Partie 2: Méthode de détermination de la résistance à la
fragmentation par l'essai Los Angeles
Reference number
ISO 20290-2:2019(E)
©
ISO 2019
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ISO 20290-2:2019(E)
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ii © ISO 2019 – All rights reserved
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ISO 20290-2:2019(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling . 2
5 Apparatus . 2
6 Determination of resistance to fragmentation by the Los Angeles test method .3
6.1 Principle . 3
6.2 Preparation of test portion . 3
6.3 Test procedure . 4
6.4 Calculation and expression of results. 4
6.5 Test report . 4
Annex A (normative) Determination of the resistance to fragmentation of aggregates for
larger size aggregates . 5
Annex B (normative) Alternative narrow range classifications for the Los Angeles test .6
© ISO 2019 – All rights reserved iii
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ISO 20290-2:2019(E)
Foreword
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
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
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on the ISO list of patent declarations received (see www .iso .org/ patents).
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expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 71, Concrete, reinforced concrete and pre-
stressed concrete, Subcommittee SC 1, Test methods for concrete.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
A list of all parts in the ISO 20290 series can be found on the ISO website.
iv © ISO 2019 – All rights reserved
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INTERNATIONAL STANDARD ISO 20290-2:2019(E)
Aggregates for concrete — Test methods for mechanical
and physical properties —
Part 2:
Method for determination of resistance to fragmentation
by Los Angeles Test (LA-Test)
1 Scope
This document describes the Los Angeles test, for determining the resistance to fragmentation of
coarse aggregates.
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 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes
of openings
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/
3.1
Los Angeles coefficient
LA
percentage of the test portion (3.1) passing a pre-determined sieve after completion of the test
3.2
test portion
sample used as a whole in a single test
3.3
laboratory sample
reduced sample derived from a bulk sample for laboratory testing
3.4
constant mass
series of successive weighings after drying at least 1 h apart not differing by more than 0,1 %
Note 1 to entry: In many cases, constant mass can be achieved after a test portion (3.1) has been dried for a
pre-determined period in a specified oven (see 5.1.3) at (105 ± 5) °C. Test laboratories may determine the time
required to achieve constant mass for specific types and sizes of sample dependent on the drying capacity of the
oven used.
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ISO 20290-2:2019(E)
4 Sampling
The sample used for the test (the laboratory sample) may be taken in accordance with the procedure
described in the relevant national standards.
5 Apparatus
5.1 General
5.1.1 Test sieves, conforming to ISO 565 or relevant national standards with aperture sizes as 1,6 mm,
10 mm, 11,2 mm (or 12,5 mm), 14 mm and 20 mm.
5.1.2 Balance, capable of weighing the test portion to an accuracy of 0,1 % of the mass of the test
portion.
5.1.3 Ventilated oven, controlled to maintain a temperature of (105 ± 5) °C.
5.1.4 Equipment, for reducing the laboratory sample to a test portion. National standards may be
referred.
5.2 Los Angeles test machine — Figure 1 shows a typical Los Angeles machine.
Key
d internal diameter (711 ± 5) mm
l internal length (508 ± 5) mm
1 shelf
2
...
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