ISO 18985:2025

Recycled aggregates for concrete

This document provides principles and framework for use of recycled aggregates for concrete, which are produced from used resources primarily in the form of waste concrete. This document is intended to accelerate the use of recycled aggregates produced from construction and demolition wastes such as waste concrete and demolished masonry units. This document complements ISO 19595, natural aggregates for concrete, which does not include the minimum requirements for the recycled aggregates for concrete.

Titre manque

General Information

• Status: Published
• Publication Date: 30-Jun-2025
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: ISO/TC 71/SC 3 - Concrete production and execution of concrete structures
• Drafting Committee: ISO/TC 71/SC 3 - Concrete production and execution of concrete structures
• Current Stage: 6060 - International Standard published
• Start Date: 01-Jul-2025
• Due Date: 24-Mar-2026
• Completion Date: 01-Jul-2025

Standards Content (Sample)

International
Standard
ISO 18985
First edition
Recycled aggregates for concrete
2025-07
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 2
5 General requirements . 3
5.1 General .3
5.2 Type of recycled aggregates .3
5.3 Class of recycled aggregates .3
6 Geometric requirements . 3
6.1 General .3
6.2 Grading .3
6.3 Particle shape .3
6.4 Fines content .3
7 Physical requirements . 4
7.1 General .4
7.2 Oven dry density .4
7.3 Water absorption .4
7.4 Resistance to fragmentation by LA abrasion .4
7.5 Impurities . .4
7.5.1 Organic impurity .4
7.5.2 Inorganic impurity .5
7.6 Others .5
8 Chemical requirements . 5
8.1 General .5
8.2 Chloride .5
8.3 Sulfate .5
9 Durability . 6
9.1 General .6
9.2 Soundness .6
9.3 Alkali-silica reactivity.6
10 Transportation and storage . 6
10.1 Transportation .6
10.2 Storage .6
11 Sampling and test methods . 6
11.1 Sampling .6
11.2 Test methods .6
12 Inspection . 7
13 Marking and labeling . 7
14 Reporting . 7
Annex A (Normative) Test method for impurity contents of recycled aggregates . 8
Annex B (Informative) Application to concrete .12
Annex C (Informative) Method for freezing and thawing test of recycled coarse aggregate Class
1 and Class 2.13
Bibliography . 17

iii
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 through
ISO technical 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
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and 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
prestressed concrete, Subcommittee SC 3, Concrete production and execution of concrete structures.
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.

iv
Introduction
The construction industry generates waste from various activities throughout the life cycle of buildings and
civil engineering works. The wastes from the construction phase and the demolition phase, often called
the construction and demolition waste, contain resources suitable for potential reuse in new construction.
Concrete constitutes a major portion of construction and demolition waste in many countries. Landfilling
of waste concrete is increasing in many countries and causes a shortage of available land area. It can also
contaminate water and soil in the vicinity of the landfill site, usually due to alkalinity, and bring about social,
economic, and environmental issues.
The waste concrete can be recycled in the form of aggregates for concrete after processing by crushing
and sorting. This document primarily deals with the recycling of waste concrete in the form of recycled
aggregates that can be used to produce concrete as a replacement for natural aggregates. This is the subject
of growing interest due to increasing concrete construction and dwindling natural resources which are used
as constituent materials to produce concrete. In some countries, the most abundant form of construction
and demolition waste may not be the waste concrete, but other form
...

International
Standard
ISO 18985
First edition
Recycled aggregates for concrete
PROOF/ÉPREUVE
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 2
5 General requirements . 3
5.1 General .3
5.2 Type of recycled aggregates .3
5.3 Class of recycled aggregates .3
6 Geometric requirements . 3
6.1 General .3
6.2 Grading .3
6.3 Particle shape .3
6.4 Fines content .3
7 Physical requirements . 4
7.1 General .4
7.2 Oven dry density .4
7.3 Water absorption .4
7.4 Resistance to fragmentation by LA abrasion .4
7.5 Impurities . .4
7.5.1 Organic impurity .4
7.5.2 Inorganic impurity .5
7.6 Others .5
8 Chemical requirements . 5
8.1 General .5
8.2 Chloride .5
8.3 Sulfate .5
9 Durability . 6
9.1 General .6
9.2 Soundness .6
9.3 Alkali-silica reactivity.6
10 Transportation and storage . 6
10.1 Transportation .6
10.2 Storage .6
11 Sampling and test methods . 6
11.1 Sampling .6
11.2 Test methods .6
12 Inspection . 7
13 Marking and labeling . 7
14 Reporting . 7
Annex A (Normative) Test method for impurity contents of recycled aggregates . 8
Annex B (Informative) Application to concrete .12
Annex C (Informative) Method for freezing and thawing test of recycled coarse aggregate Class
1 and Class 2.13
Bibliography . 17
PROOF/ÉPREUVE
iii
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 through
ISO technical 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
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and 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
prestressed concrete, Subcommittee SC 3, Concrete production and execution of concrete structures.
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.
PROOF/ÉPREUVE
iv
Introduction
The construction industry generates waste from various activities throughout the life cycle of buildings and
civil engineering works. The wastes from the construction phase and the demolition phase, often called
the construction and demolition waste, contain resources suitable for potential reuse in new construction.
Concrete constitutes a major portion of construction and demolition waste in many countries. Landfilling
of waste concrete is increasing in many countries and causes a shortage of available land area. It can also
contaminate water and soil in the vicinity of the landfill site, usually due to alkalinity, and bring about social,
economic, and environmental issues.
The waste concrete can be recycled in the form of aggregates for concrete after processing by crushing
and sorting. This document primarily deals with the recycling of waste concrete in the form of recycled
aggregates that can be used to produce concrete as a replacement for natural aggregates. This is the subject
of growing interest due to increasing concrete construction and dwindling natural resources which are used
as constituent materials to produce concrete. In some countries, the most abundant form of construction
and demolition waste may
...

ISO/DISPRF 18985
ISO/TC 71/SC 3
Secretariat: SN
Date: 2025-04-24
Recycled aggregates for concrete
DIS stage
Warning for WD’s and CD’s
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change
without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which
they are aware and to provide supporting documentation.

PROOF
ISO/DISPRF 18985:20242025(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
iii
ISO/DISPRF 18985:20242025(en)
Contents
Foreword . vi
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 General requirements . 3
5.1 General. 3
5.2 Type of recycled aggregates . 3
5.3 Class of recycled aggregates . 3
6 Geometric requirements . 3
6.1 General. 3
6.2 Grading . 3
6.3 Particle shape . 3
6.4 Fines content . 4
7 Physical requirements . 4
7.1 General. 4
7.2 Oven dry density . 4
7.3 Water absorption . 4
7.4 Resistance to fragmentation by LA abrasion . 4
7.5 Impurities . 5
7.6 Others . 5
8 Chemical requirements . 5
8.1 General. 5
8.2 Chloride . 5
8.3 Sulfate . 6
9 Durability . 6
9.1 General. 6
9.2 Soundness . 6
9.3 Alkali-silica reactivity . 6
10 Transportation and storage . 6
10.1 Transportation . 6
10.2 Storage . 6
11 Sampling and test methods . 7
11.1 Sampling . 7
11.2 Test methods . 7
12 Inspection . 7
13 Marking and labeling . 7
14 Reporting . 8
Annex A (Normative) Test method for impurity contents of recycled aggregates . 9
Annex B (Informative) Application to concrete . 13
Annex C (Informative) Method for freezing and thawing test of recycled coarse aggregate Class
1 and Class 2. 14
iv
ISO/DISPRF 18985:20242025(en)
Bibliography . 18

v
ISO/DISPRF 18985:20242025(en)
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 through
ISO technical 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 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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and 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 prestressed
concrete, Subcommittee SC 3, Concrete production and execution of concrete structures.
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.
vi
ISO/DISPRF 18985:20242025(en)
Introduction
The construction industry generates waste from various activities throughout the life cycle of buildings and
civil engineering works. The wastes from the construction phase and the demolition phase, often called the
construction and demolition waste, contain resources suitable for potential reuse in new construction.
Concrete constitutes a major portion of construction and demolition waste in many countries. Landfilling of
waste concrete is increasing in many countries and causes a shortage of available land area. It can also
contaminate water and soil in the vicinity of the landfill site, usually due to alkalinity, and bring about social,
economic, and environmental issues.
The waste concrete can be recycled in the form of aggregates for concrete after processing by crushing and
sorting. This document primarily deals with the recycling of waste concrete in the form of recycled aggregates
that can be used to produce concrete as a replacement for natural aggregates. This is the subject of growing
interest due to increasing concrete construction and dwindling natural resources which are used as
constituent materials to produce concrete. In some countries, the most abundant form of construction and
demolition waste may not be the waste concrete, but other forms of waste such as demolished masonry units.
This document sets the minimum requirements for the recycled aggregates made from waste concrete and
others, used to produce concrete in a unified manner. Figure 1 shows how to use this document with other
ISO standards.
vii
ISO/DISPRF 18985:20242025(en)
Key
information flow:standard A provides information to standard B

hierarchy:standard B complements standard A
Figure 1 — Relationship of this document to other International Standards
viii
ISO/DISPRF 18985:20242025(en)
Recycled aggregates for concrete
1 Scope
This document provides principles and framework for use of recycled aggregates for concrete, which are
produced from used resources primarily in the form of waste concrete. This document is intended to
accelerate the use of recycled aggregates produced from construction and demolition wastes such as waste
concrete and demolished masonry units. This document complements ISO 19595, natural aggregates for
concrete, which does not include the minimum requirements for the recycled aggregates for 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 19595:2017, Natural aggregates for concrete
ISO 20290-1, Aggregates for concrete — Test methods for mechanical and physical properties — Part 1:
Determination of bulk density, particle density, particle mass-per-volume and water absorption
ISO 20290-2, 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)
ISO 20290-5, Aggregates for concrete — Test methods for mechanical and phys
...