ISO 23945-2

• Abstract:

  This document specifies a method for obtaining samples of fresh or hardened sprayed concrete or mortar from the basic mix and in-situ, for preparing test panels and for testing specimens sawed or cored from the panels depending on the property to be measured and its associated test method.

• Status: Not Published
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: ISO/TC 71/SC 1 - Test methods for concrete
• Drafting Committee: ISO/TC 71/SC 1 - Test methods for concrete
• Current Stage: 6000 - International Standard under publication
• Start Date: 10-Sep-2026
• Completion Date: 19-Sep-2026

Overview

ISO 23945-2: Test methods for sprayed concrete - Part 2: Sampling fresh and hardened concrete specifies standardized procedures for obtaining samples of sprayed concrete (also known as shotcrete) and mortar, both in the fresh state and after hardening. The standard applies to materials sampled from the basic mix, in-situ works, or from test panels. The aim is to enable accurate and consistent preparation and testing of specimens that reflect actual site or production conditions. This document supports quality assurance in construction where sprayed concrete is extensively used, such as tunnelling, mining, infrastructure repair, and specialized concrete applications.

Key Topics

• Sampling Procedures: Methods for obtaining representative samples of both fresh and hardened sprayed concrete directly from the mixer, in-situ structures, or prepared test panels.
• Equipment Requirements: Specifications for mixers, spraying equipment, scoops, trowels, moulds, and coring/cutting equipment that align with referenced standards such as ISO 18650-1 (Concrete mixers).
• Fresh Concrete Sampling:
  • Extracting increments from the mixer at various points to form a homogeneous sample before spray application.
  • Using non-absorbent tools for precise, uncontaminated sampling.
• Sprayed Test Panels:
  • Panel preparation guidelines for both manual and robotic spraying, including minimum size, formwork materials, and placement procedures.
  • Recommendations to match panel preparation with site application techniques.
• Curing and Storage: Defined procedures for wrapping, curing, and storing samples and panels to ensure specimen consistency prior to testing.
• Defective Zones and Marking: Identification zones to avoid during sampling and marking protocols for traceability of specimens.
• Hard Sample Extraction: Procedures for coring or sawing specimens from hardened sprayed concrete in panels or in-situ, referencing ISO 1920-6 for core sampling.
• Sample Identification: Systematic labelling for all specimens to document location, orientation, composition, and operator details, ensuring traceability and result reliability.

Applications

ISO 23945-2 is vital in a range of applications involving sprayed concrete, such as:

• Tunneling and Mining: Quality assurance of shotcrete used for ground stabilization and lining in underground works.
• Infrastructure Repair & Restoration: Reliable methods for evaluating in-situ repairs in bridges, dams, tunnels, and retaining walls.
• New Construction: Essential for sprayed concrete application in complex structural forms or where traditional casting is impractical.
• Testing Laboratories: Provides a unified framework for sample preparation, supporting laboratories in delivering accurate, repeatable test results.
• Contractual Specifications: Ensures contractors and inspectors reference consistent sampling protocols, which are crucial in solving disputes and fulfilling project specifications.

By following this international standard, organizations can increase confidence in the assessment of mechanical and durability properties of sprayed concrete, supporting long-term safety and performance.

Related Standards

• ISO 1920-6: Testing of concrete - Part 6: Sampling, preparing, and testing of concrete cores
• ISO 18650-1: Building construction machinery and equipment - Concrete mixers - Part 1: Commercial specifications
• EN 14488-1: Testing sprayed concrete - Part 1: Sampling fresh and hardened concrete
• ASTM C1140/C1140M: Practice for Preparing and Testing Specimens from Shotcrete Test Panels
• ASTM C1604/C1604M: Standard Test Method for Obtaining and Testing Drilled Cores of Shotcrete

These related standards complement ISO 23945-2 by addressing test methods for sprayed concrete and shotcrete, equipment requirements, and specimen management, supporting harmonized concrete testing practices worldwide.

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Keywords: ISO 23945-2, sprayed concrete standard, shotcrete sampling, fresh concrete sampling, hardened concrete testing, concrete test panels, ISO standards for concrete, concrete sample preparation, quality control in sprayed concrete, construction materials testing.

International
Standard
First edition
Test methods for sprayed
concrete —
Part 2:
Sampling fresh and hardened
concrete
PROOF/ÉPREUVE
Reference number
© ISO 2026
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 Principle . 1
5 Apparatus . 1
5.1 Mixer .1
5.2 Spraying equipment .1
5.3 Scoop .2
5.4 Trowel .2
5.5 Moulds .2
5.6 Coring or cutting equipment .2
6 Procedures . 2
6.1 General .2
6.2 Obtaining a fresh sample from the basic mix before spraying .2
6.3 Obtaining a fresh sample from in-situ sprayed concrete .2
6.4 Making a test panel .3
6.5 Obtaining a fresh sample from a test panel .3
6.6 Curing .4
6.7 Obtaining a hardened sample from in-situ sprayed concrete .4
6.8 Obtaining a hardened sample from a test panel .4
6.9 Shape and size of hardened samples . .4
7 Identification of sample. 4
7.1 Fresh samples .4
7.2 Hardened samples .4
Bibliography . 5
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 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).
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 pre-
stressed concrete, Subcommittee SC1, Test methods for concrete.
A list of all parts in the ISO 23945 series can be found on the ISO website.
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
Sprayed concrete is widely used for the stabilization of structures in a very short time and for concrete
applications without using moulds. In addition to being ideal for ground support in tunnelling and mining,
sprayed concrete is also used in repairs, restoration, new constructions and many other fields.
The requirements for properties, test methods, standards and specifications for the spray forming process
of concrete are different from those of cast forming concrete. This document is intended to provide a
normative test method for sprayed concrete.
This document is applied under various climatic and geographical conditions, various levels of protection
and under different established regional traditions and experiences. Consequently, this document
...

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ISO/PRF 23945-2
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Test methods for sprayed concrete —
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Part 2:
Sampling fresh and hardened concrete

PROOF
ISO/PRF 23945-2:2026(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/PRF 23945-2:2026(en)
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
5.1 Mixer . 2
5.2 Spraying equipment . 2
5.3 Scoop . 2
5.4 Trowel . 2
5.5 Moulds . 2
5.6 Coring or cutting equipment . 2
6 Procedures . 2
6.1 General . 2
6.2 Obtaining a fresh sample from the basic mix before spraying . 3
6.3 Obtaining a fresh sample from in-situ sprayed concrete . 3
6.4 Making a test panel. 3
6.5 Obtaining a fresh sample from a test panel . 4
6.6 Curing . 6
6.7 Obtaining a hardened sample from in-situ sprayed concrete . 6
6.8 Obtaining a hardened sample from a test panel . 6
6.9 Shape and size of hardened samples . 6
7 Identification of sample . 6
7.1 Fresh samples . 6
7.2 Hardened samples . 6
Bibliography . 7

iv
ISO/PRF 23945-2:2026(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 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).
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 pre-
stressed concrete, Subcommittee SC1, Test methods for concrete.
A list of all parts in the ISO 23945 series can be found on the ISO website.
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.
v
ISO/PRF 23945-2:2026(en)
Introduction
Sprayed concrete is widely used for the stabilization of structures in a very short time and for concrete
applications without using moulds. In addition to being ideal for ground support in tunnelling and mining,
sprayed concrete is also used in repairs, restoration, new constructions and many other fields.
The requirements for properties, test methods, standards and specifications for the spray forming process of
concrete are different from those of cast forming concrete. This document is intended to provide a normative
test method for sprayed concrete.
This document is applied under various climatic and geographical conditions, various levels of protection and
under different established regional traditions and experiences. Consequently, this document includes
conditions for tests covering standard, tropical and subtropical region environments.
This document is intended for use with other parts of the ISO 23945 series which provide requirements
associated with the level of quality specified and the methods to be employed for the execution of sprayed
concrete.
vi
ments and secretariat observations Date: 2025-12-22 Document: ISO/DIS 23945-2 Project:

ause/ Paragraph/ Type of Comments Proposed change Observations of the
bclause Figure/ comment secretariat
Table/
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(e.g. Table 1)
ISO/PRF 23945-2:2026(en)
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