ISO 16311-4:2024

Maintenance and repair of concrete structures - Part 4: Execution of repairs

This document provides requirements for substrate condition before and during application, including structural stability, storage of materials, the preparation, and application of products and systems for repair of concrete structures, including quality control and qualifications of personnel, maintenance, health and safety, and the environment.

Entretien et réparation des structures en béton — Partie 4: Exécution des réparations

General Information

• Status: Published
• Publication Date: 12-Mar-2024
• ICS: 91.100.30 - Concrete and concrete products
• Technical Committee: ISO/TC 71/SC 7 - Maintenance and repair of concrete structures
• Drafting Committee: ISO/TC 71/SC 7/WG 2 - Condition Assessment, and Design & Execution of Repairs
• Current Stage: 6060 - International Standard published
• Start Date: 13-Mar-2024
• Due Date: 09-Jun-2025
• Completion Date: 13-Mar-2024

Relations

• Revises: ISO 16311-4:2014 - Maintenance and repair of concrete structures - Part 4: Execution of repairs and prevention
• Effective Date: 23-Apr-2020

Overview - ISO 16311-4:2024 (Maintenance and repair of concrete structures - Part 4: Execution of repairs)

ISO 16311-4:2024 defines requirements for the on-site execution of repairs to concrete structures. It covers substrate condition before and during application, structural stability, storage and handling of materials, preparation and application of repair products and systems, and measures for quality control, personnel qualifications, maintenance, health, safety and environmental protection. The second edition updates and clarifies references and editorial matters and is part of the ISO 16311 series on maintenance and repair of concrete.

Key technical topics and requirements

• Structural stability during works - Maintaining safety and stability before, during and after repair in line with ISO 16311-3.
• Substrate preparation - Cleaning, roughening, removal of unsound concrete and preparation of reinforcement (cleaning, coating or replacement where necessary).
• Repair methods - Requirements for bonding, hand-applied mortars and concretes, sprayed repair mortar/concrete, cast repair materials, anchoring, plate bonding and fibre-reinforced polymer (FRP) strengthening.
• Curing and wet-on-wet applications - Considerations for curing times and compatible successive layers.
• Defects from reinforcement corrosion - Procedures for coating, removal or replacement of corroded reinforcement and addressing chloride-induced or carbonation-induced deterioration.
• Quality control and testing - Site tests and observations, test specimen handling and performance checks referenced to standards such as the ISO 1920 series for concrete testing.
• Personnel, HSE and environment - Qualifications of applicators, safety procedures, storage of materials and environmental protection during remedial works.
• Electrochemical methods - Recognition of methods such as cathodic protection, re-alkalisation and chloride extraction as part of repair options (listed in the introduction).

Practical applications - who uses ISO 16311-4:2024

• Structural and repair engineers specifying and designing remedial works.
• Contractors and specialist applicators executing concrete repairs, surface preparation and placement of repair systems.
• Asset owners, facility managers and inspectors developing maintenance plans and quality plans for repairs.
• Test laboratories and QA personnel performing site verification and acceptance testing.
  Use cases include bridge deck repairs, concrete façade remediation, marine and infrastructure repairs, and refurbishment of reinforced concrete elements.

Related standards and references

Relevant documents cited include ISO 16311-1, ISO 16311-2, ISO 16311-3, the ISO 1920 series (testing of concrete), ISO 22966 (execution of concrete structures), ISO 5091 (structural intervention), and standards on coatings and surface preparation (ISO 4624, ISO 8501 series). These provide complementary guidance for design, testing and execution.

Standards Content (Sample)

International
Standard
ISO 16311-4
Second edition
Maintenance and repair of concrete
2024-03
structures —
Part 4:
Execution of repairs
Entretien et réparation des structures en béton —
Partie 4: Exécution des réparations
Reference number
© ISO 2024
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 . 2
4 Structural stability during execution of repairs . 3
5 General requirements . 3
6 Methods of repair . 4
7 Preparation of substrate . 9
7.1 General .9
7.2 Preparation of concrete .11
7.2.1 General .11
7.2.2 Cleaning .11
7.2.3 Roughening.11
7.2.4 Concrete removal .11
7.3 Preparation of reinforcement . 12
7.3.1 General . 12
7.3.2 Cleaning . 12
8 Application of products and systems .12
8.1 General . 12
8.2 Structural strengthening to restore member capacity — methods . 15
8.2.1 Bonding . 15
8.2.2 Hand applied mortar and concrete . 15
8.2.3 Sprayed repair mortar or concrete . 15
8.2.4 Cast repair mortar or concrete . 15
8.2.5 Curing .16
8.2.6 Cracks and joints .16
8.2.7 Surface coatings and other treatments .16
8.2.8 Anchoring .17
8.2.9 Plate bonding and fibre-reinforced polymer (FRP) strengthening .17
8.3 Defects caused by reinforcement corrosion .17
8.3.1 Coating reinforcement . .17
8.3.2 Removal .17
8.3.3 Replacement .17
9 Quality control .18
9.1 General .18
9.2 Quality control tests and observations .18
10 Maintenance following completion of remedial action .18
11 Health, safety and the environment . . 19
Annex A (informative) Commentary on the execution of repairs .29

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 pre-
stressed concrete, Subcommittee SC 7, Maintenance and repair of concrete structures.
This second edition cancels and replaces the first edition (ISO 16311-4:2014) which has been technically
revised.
The main changes are as follows:
— the title has been changed due to clarification of the definition of the term;
— some relevant reference standards have been clarified;
— some editorial corrections have been made.
A list of all parts in the ISO 16311 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.

iv
Introduction
This document defines and specifies site application of products and systems and quality control of repairs.
The execution of maintenance and repair of concrete structures is an important and integral part of the
complex process of repair, and this document specifies how it is carried out. This document incorporates
rules for the use of maintenance and repair materials and systems. Maintenance and repair methods
applying traditional concrete construction work are listed in this document. Maintenance and repair
methods applying electrochemical methods, e.g. cathodic protection, re-alkalisation of carbonated concrete,
and chloride extraction, are listed in this document.

v
International Standard ISO 16311-4:2024(en)
Maintenance and repair of concrete structures —
Part 4:
Execution of repairs
1 Scope
This document provides requirements for substrate condition before and during application, including
structural stability, storage of materials, the preparation, and application of products and systems for repair
of concrete structures, including quality control and qualifications of personnel, maintenance, health and
safety, and the environment.
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 1920-2, Testing of concrete — Part 2: Properties of fresh concrete
ISO 1920-3, Testing of concrete — Part 3: Making and curing test specimens
ISO 1920-4, Testing of concrete — Part 4: Strength of hardened concrete
ISO 1920-5, Testing of concrete — Part 5: Density and water penetration depth
ISO 1920-6, Testing of concrete — Part 6: Sampling, preparing and testing of concrete cores
ISO 1920-7, Testing of concrete — Part 7: Non-destructive tests on hardened concrete
ISO 2394, General principles on reliability for structures
ISO 2409, Paints and varnishes — Cross-cut test
ISO 2808:2019, Paints and varnishes — Determination of film thickness
ISO 3274, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Nominal characteristics
of contact (stylus) instruments
ISO 4624, Paints and varnishes — Pull-off test for adhesion
ISO 4628-1, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size
of defects, and of intensity of uniform changes in appearance — Part 1: General introduction and designation
system
ISO 4628-2, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of
defects, and of intensity of uniform changes in appearance — Part 2: Assessment of degree of blistering
ISO 4628-3, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of
defects, and of intensity of uniform changes in appearance — Part 3: Assessment of degree of rusting
ISO 4628-4, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity and size of
defects, and of intensity of uniform changes in appearance — Part 4: Assessment of degree of cracking

ISO 4628-5, Paints and varnishes — Evaluation of quantity and size of defects, and of intensity of uniform
changes in appearance — Part 5: Assessment of degree of flaking
ISO 4628-6, Paints and varnishes — Evaluation of quantity and size of defects, and of intensity of uniform
changes in appearance — Part 6: Assessment of degree of chalking by tape method
ISO 5091 (all parts), — Structural intervention of existing concrete structures using cementitious materials
ISO 6935-2, Steel for the reinforcement of concrete — Part 2: Ribbed bars
ISO 8501-1, Preparation of steel substrates before application of paints and related products — Visual
assessment of surface cleanliness — Part 1: Rust grades and preparation grades of uncoated steel substrates and
of steel substrates after overall removal of previous coatings
ISO 8502-2, Preparation of steel substrates before application of paints and related products — Tests for the
assessment of surface cleanliness — Part 2: Laboratory determination of chloride on cleaned surfaces
ISO 8502-3, Preparation of steel substrates before application of paints and related products — Tests for the
assessment of surface cleanliness — Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-
sensitive tape method)
ISO 8502-4, Preparation of steel substrates before application of paints and related products — Tests for the
assessment of surface cleanliness — Part 4: Guidance on the estimation of the probability of condensation prior
to paint application
ISO 13822, Bases for design of structures — Assessment of existing structures
ISO 14654, Epoxy-coated steel for the reinforcement of concrete
ISO 14657, Zinc-coated steel for the reinforcement of concrete
ISO 16311-1, Maintenance and repair of concrete structures — Part 1: General principles
ISO 16311-2, Maintenance and repair of concrete structures — Part 2: Assessment of existing concrete structures
ISO 16311-3:2014, Maintenance and repair of concrete structures — Part 3: Design of repairs and prevention
ISO 19338, Performance and assessment requirements for design standards on structural concrete
ISO 21920-3, Geometrical product specifications (GPS) — Surface texture: Profile — Part 3: Specification
operators
ISO 22965-1, Concrete — Part 1: Methods of specifying and guidance for the specifier
ISO 22965-2, Concrete — Part 2: Specification of constituent materials, production of concrete and compliance
of concrete
ISO 22966, Execution of concrete structures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16311-1, ISO 2394, ISO 13822 and
ISO 19338 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/

3.1
bond
adhesion of the applied product or system to the substrate
Note 1 to entry: The bond requirements for a given repair can range from negligible to firmly adherent.
3.2
cement grout
mixture of cement, water, and, in some cases, admixtures
3.3
cementitious repair products and systems
hydraulic or polymer hydraulic mortars, concretes and grouts
3.4
dew point
temperature at which water vapour condenses
3.5
mortars
concrete
hydraulic, polymer hydraulic, and polymer mortar and concrete
3.6
pre-formed hole
hole or slot formed or cut in concrete into which reinforcement or other fixing is to be anchored
3.7
quality plan
programme to ensure that the activities of a process are undertaken to comply with the intended design
3.8
sprayed mortar or concrete
mortar or concrete applied under pressure through a nozzle delivered through pipes
3.9
wet on wet
application of a cementitious mortar or concrete onto the surface of a similar material which has set but not
hardened
4 Structural stability during execution of repairs
Safety and stability before, during and after repair shall be maintained in accordance with ISO 16311-3.
Any period required for gain of strength of the repair products and systems shall be a part of the duration of
the repair.
5 General requirements
Consideration shall be given to the chemical, electrochemical and physical condition of the substrate and any
contaminants, the ability of the structure to accept loading, movement and vibration during repair, ambient
conditions and the characteristics of the materials contained in the structure and those of repair products
and systems.
The following requirements shall be met.
— The achievement of the required condition of the substrate regarding cleanliness, roughness, cracking,
tensile and compressive strength, chloride or other contaminant and their penetration, depth of
carbonation, moisture content, temperature, and degree of corrosion of reinforcement.

— The achievement of the compatibility of the original concrete and reinforcement with repair products
and systems and compatibility between any different products and systems, including avoiding the risk
of creating conditions which can cause corrosion.
— The achievement of the specified properties of products and systems when applied and in their hardened
condition regarding the fulfilment of their purpose for repair of the structure.
— The achievement of the required storage and application conditions regarding ambient temperature,
humidity and dew point, wind force and precipitation, and any temporary protection which is needed.
6 Methods of repair
The remedies and methods of repair, given in ISO 16311-3:2014, Table 1, are described below, excluding
those methods specified in standards valid in the place of use.
The preparation of substrate, application of products and systems, quality control, and maintenance for each
method shall comply with Clauses 7, 8, 9 and 10.
The relevant subclauses are given in Table 1 for each method together with any deviations, additions,
necessary precautions and limitations.

Table 1 — Table for each method together with any deviations, additions, necessary precautions and limitations
Preparation Application Quality control
Repair remedies and methods
See subclauses See subclauses See subclauses
Method Methods to satisfy remedy 1 – Protection against ingress
The following methods satisfy the remedy of reducing or preventing the ingress of adverse agents, e.g. water, other liquids, vapour gas such as carbon dioxide, chemicals such as chlorides
and biological agents.
Hydrophobic impregnation
1.1 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method applies a product to prevent or reduce the passage of water by lining the surface pores with
material with hydrophobic properties.
Impregnation
1.2 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method is to apply liquid products which penetrate the concrete and block the pore system.
Coating
1.3 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.7 9.1, 9.2
This method applies a product to the surface of the concrete to prevent the passage of agents.
Surface bandaging of cracks
a
1.4 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.2, 8.2.5, 8.2.6 9.1, 9.2
The method seals cracks in the concrete to prevent the passage of deleterious agents. Refer to A.3.
Filling of cracks
a
1.5 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.2, 8.2.5, 8.2.6 9.1, 9.2
This method fills cracks to protect against ingress.
Transforming cracks into joints
1.6 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.6 9.1, 9.2
This method makes use of existing cracks as an integral part of the structure. Refer to A.3.
Erecting external panels
1.7 System dependent System dependent System dependent
This method installs barrier panels to protect or encapsulate the deteriorating substrate.
Applying membranes
1.8 System dependent System dependent System dependent
This method installs proprietary systems to protect or encapsulate the concrete substrate.
Method Methods to satisfy remedy 2 – Moisture control
The following methods satisfy the remedy of adjusting and maintaining the moisture content in the concrete between a specified range of values.
Hydrophobic impregnation
2.1 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method applies a product to reduce the penetration of water and other agents into the treated concrete
by lining the surface pores with materials with hydrophobic properties.
Impregnation
2.2 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method applies liquid products which penetrate the concrete and block the pore system.
Coating
2.3 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.7 9.1, 9.2
This method applies a product to the surface of the concrete to prevent the passage of water or water vapour.
2.4 Erecting external panels (refer to method 1.7) System dependent System dependent System dependent
Electrochemical treatment
2.5 System dependent System dependent System dependent
This method applies an electro-osmotic pulse to reduce water content of the concrete. Refer to A.3.
a
Concrete at the edges of cracks shall be prepared and repaired in accordance with Clauses 7 and 8. Subclauses 8.2.2 and 8.2.5 apply only to cementitious grouts.
b
Subclauses 8.2.1 and 8.2.5 apply only to cementitious grouts.
c
Coating to concrete which prevents repassivation shall be removed and the concrete shall be cleaned, roughened and removed where necessary.
d
Concrete shall be removed only to the depth to which it has been cracked or loosened. Embedded reinforcement shall be cleaned in accordance to 7.3.1 and 7.3.2.
e
Hydraulic mortar or concrete shall be used.

Table 1 (continued)
Preparation Application Quality control
Repair remedies and methods
See subclauses See subclauses See subclauses
Method Methods to satisfy remedy 3 – Concrete restoration
The following methods satisfy the remedy of restoring the original concrete of a member of the structure to the originally specified shape and function. Restoring the concrete structure by
replacing part of it.
Hand-applied localized patches 7.1, 7.2.1, 7.2.2, 7.2.3,
3.1 8.1, 8.2.1, 8.2.2, 8.2.5 9.1, 9.2
7.2.4
Recasting components with concrete or mortar 8.1, 8.2.1, 8.2.2, 8.2.5,
7.1, 7.2.1, 7.2.2, 7.2.3,
3.2 ISO 22965-1, ISO 22965-2 and 9.1, 9.2
7.2.4 and ISO 22966
ISO 22966
Spraying concrete or mortar 7.1, 7.2.1, 7.2.2, 7.2.3, 8.1, 8.2.1, 8.2.2, 8.2.5 and
3.3 9.1, 9.2
7.2.4 and ISO 22966 ISO 22966
3.4 Replacing structural members ISO 2394 ISO 22966 9.1, 9.2
Method Methods to satisfy remedy 4 – Structural strengthening
The following methods satisfy the remedy of increasing or restoring the structural load bearing capacity of a member of the concrete structure.
Adding or replacing embedded or external reinforcing bars 7.1, 7.3.1, 7.3.2, 8.2.1, 8.1, 8.2.8, 8.3.1, 8.3.3 and
4.1 9.1, 9.2
8.3.2 ISO 22966
4.2 Adding reinforcement anchored in pre-formed or drilled holes 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.8, 8.3.1, 8.3.3 9.1, 9.2
Bonding plate reinforcement
7.1, 7.2.1, 7.2.2, 7.2.3,
4.3 8.1, 8.2.1, 8.2.6, 8.2.9 9.1, 9.2
7.2.4
This method bonds the strengthening plates externally to a member of the concrete structure.
Adding mortar or concrete
7.1, 7.2.1, 7.2.2, 7.2.3, 8.1, 8.2.1, 8.2.2, 8.2.3, 8.2.4,
4.4 9.1, 9.2
7.2.4 8.2.5
This method bonds additional mortar or concrete to the concrete structure.
Injecting cracks, voids or interstices
4.5 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.2, 8.2.5, 8.2.6 9.1, 9.2
This method injects the concrete with appropriate fluid.
4.6 Filling cracks, voids, or interstices 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.2, 8.2.5, 8.2.6 9.1, 9.2
4.7 Prestressing (post-tensioning) or FRP strengthening ISO 2394 ISO 22966 9.1, 9.2
Method Methods to satisfy remedy 5 – Increasing physical resistance
The following methods satisfy the remedy of increasing resistance to physical or mechanical attack.
Coating
5.1 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.7 9.1, 9.2
This method increases the physical resistance with a coating.
Impregnation
5.2 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method applies liquid products which penetrate the concrete.
Adding mortar or concrete
7.1, 7.2.1, 7.2.2, 7.2.3, 8.1, 8.2.1, 8.2.2, 8.2.3, 8.2.4,
5.3 9.1, 9.2
7.2.4 8.2.5
This method bonds additional mortar or concrete to the concrete structure.
a
Concrete at the edges of cracks shall be prepared and repaired in accordance with Clauses 7 and 8. Subclauses 8.2.2 and 8.2.5 apply only to cementitious grouts.
b
Subclauses 8.2.1 and 8.2.5 apply only to cementitious grouts.
c
Coating to concrete which prevents repassivation shall be removed and the concrete shall be cleaned, roughened and removed where necessary.
d
Concrete shall be removed only to the depth to which it has been cracked or loosened. Embedded reinforcement shall be cleaned in accordance to 7.3.1 and 7.3.2.
e
Hydraulic mortar or concrete shall be used.

Table 1 (continued)
Preparation Application Quality control
Repair remedies and methods
See subclauses See subclauses See subclauses
Applying membranes
5.4 System dependent System dependent System dependent
This method installs proprietary systems to protect or encapsulate the concrete substrate.
Method Methods to satisfy remedy 6 – Increasing resistance to chemicals
The following methods increase the resistance of the concrete surface to deterioration by reducing the penetration of chemical agents.
Coating
6.1 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.7 9.1, 9.2
This method increases the physical resistance with a coating.
Impregnation
6.2 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method applies liquid products that penetrate the concrete.
Adding mortar or concrete
7.1, 7.2.1, 7.2.2, 7.2.3, 8.1, 8.2.1, 8.2.2, 8.2.3, 8.2.4,
6.3 9.1, 9.2
7.2.4 8.2.5
This method bonds additional mortar or concrete to the concrete structure.
Method Methods to satisfy remedy 7 – Preserving or restoring passivity
The following methods satisfy the remedy of creating chemical conditions in which the surface of the reinforcement is maintained at or is returned to a passive condition.
Increasing cover to reinforcement with additional cementitious mortar or concrete, or applying
coatings
7.1, 7.2.1, 7.2.2, 7.2.3, 8.1, 8.2.1, 8.2.2, 8.2.3, 8.2.4,
9.1, 9.2
These methods increase cover or provide surface coatings to prevent penetration of the de-passivating agents: 7.2.4 8.2.5
7.1
9.1, 9.2
—  Concrete or mortar overlays 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.7
—  Coatings
Replacing contaminated or carbonated concrete
7.1, 7.2.1, 7.2.2, 7.2.3,
7.2 8.1, 8.2.1, 8.2.2, 8.2.5 9.1, 9.2
7.2.4
This method replaces carbonate concrete with uncontaminated mortar or concrete.
7.3 Electrochemical re-alkalisation of carbonated concrete System dependent System dependent 9.1, 9.2
c, d e
Re-alkalisation of carbonated concrete by diffusion 7.1, 7.2.1, 7.2.2, 7.2.3, 8.1, 8.2.1, 8.2.2, 8.2.3, 8.2.4,
7.4 9.1, 9.2
7.2.4 8.2.5
Electrochemical chloride extraction System dependent and
7.5 System dependent System dependent
9.1, 9.2
Applying membranes (preserving passivity only) System dependent System dependent System dependent
7.6
This method installs proprietary systems to protect or encapsulate the concrete substrate, thereby main-
taining passivity.
Method Methods to satisfy remedy 8 – Increasing resistivity
The following method satisfies the remedy of increasing the electrical resistivity of the concrete by limiting moisture content.
Hydrophobic impregnation 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
8.1
This is a method to reduce water content and as a result increase the electrical resistance of concrete.
Impregnation
8.2 7.1, 7.2.1, 7.2.2 8.1, 8.2.7 9.1, 9.2
This method applies liquid products that penetrate the concrete.
a
Concrete at the edges of cracks shall be prepared and repaired in accordance with Clauses 7 and 8. Subclauses 8.2.2 and 8.2.5 apply only to cementitious grouts.
b
Subclauses 8.2.1 and 8.2.5 apply only to cementitious grouts.
c
Coating to concrete which prevents repassivation shall be removed and the concrete shall be cleaned, roughened and removed where necessary.
d
Concrete shall be removed only to the depth to which it has been cracked or loosened. Embedded reinforcement shall be cleaned in accordance to 7.3.1 and 7.3.2.
e
Hydraulic mortar or concrete shall be used.

Table 1 (continued)
Preparation Application Quality control
Repair remedies and methods
See subclauses See subclauses See subclauses
Coating
8.3 7.1, 7.2.1, 7.2.2 8.1, 8.2.1, 8.2.7 9.1, 9.2
This method increases the physical resistance with a coating.
Method Methods to satisfy remedy 9 – Cathodic control
The following methods satisfy the remedy of creating conditions in which potentially cathodic areas of reinforcement are unable to drive an anodic reaction.
Limiting oxygen content (at the cathode) by saturation or surface coating
7.1, 7.2.1, 7.2.2 9.1, 9.2
The concrete shall be continu-
9.1 Saturation.
ously saturated with water.
7.1, 7.2.1, 7.2.2 9.1, 9.2
Surface coating.
8.1, 8.2.1, 8.2.7
Method Method to satisfy remedy 10 – Cathodic protection
10.1 Applying an electrical current to achieve a protective electrochemical potential 9.1, 9.2
Method Methods to satisfy remedy 11 – Control of anodic areas
The following methods satisfy the remedy of creating conditions in which potentially anodic areas of reinforcement are unable to take part in the corrosion reaction.
Active coating of the reinforcement
This is a method which provides either:
11.1 —  coatings to provide an alkaline environment; 7.1, 7.3.1, 7.3.2 8.1, 8.3.1 9.1, 9.2
—  coatings which function as inhibitors of electrochemical action;
—  coatings provide sacrificial galvanic reaction.
Barrier coating of the reinforcement
11.2 7.1, 7.3.1, 7.3.2 8.1, 8.3.1 9.1, 9.2
This is a method providing a barrier to prevent pore water containing chlorides or other contaminants
from reaching the reinforcement.
Applying corrosion inhibitors in or to concrete
11.3 7.1, 7.2.1, and 7.2.2. 8.1,8.2.6. 9.1, 9.2
Corrosion inhibitors are applied as a surface treatment or are added to repair products and systems. Refer
to A.3 for additional information.
Installation of discrete galvanic anodes
11.4 7.1, 7.3.1, 7.3.2 8.1, 8.3.1 9.1, 9.2
This method is intended to counteract the incipient anode effect that occurs at the perimeter of localized
concrete patch repairs.
a
Concrete at the edges of cracks shall be prepared and repaired in accordance with Clauses 7 and 8. Subclauses 8.2.2 and 8.2.5 apply only to cementitious grouts.
b
Subclauses 8.2.1 and 8.2.5 apply only to cementitious grouts.
c
Coating to concrete which prevents repassivation shall be removed and the concrete shall be cleaned, roughened and removed where necessary.
d
Concrete shall be removed only to the depth to which it has been cracked or loosened. Embedded reinforcement shall be cleaned in accordance to 7.3.1 and 7.3.2.
e
Hydraulic mortar or concrete shall be used.

7 Preparation of substrate
7.1 General
The preparation of the substrate of concrete and reinforcement shall be suitable for the required condition
of the repair work, so that the products and systems can be properly applied, and shall be carried out in such
a way as to produce repair which is in accordance with this document, ISO 16311-2 and ISO 16311-3. The
requirements for preparation are given in the following subclauses and are related to the methods of repair
in Table 2.
Table 2 — Preparation of substrate
Preparation Subclause no. References Method no. in Table 1
process (background
Hydrophobic Surface coating Filling cracks, Application of Adding rein- Installing Plate Coating
information in
impregnation voids or inter- mortar and con- forcing steel bonded rebars bonding reinforcement
Annex A)
and impregna- stices crete bars in pre-formed
tion holes
1.1, 1.2, 2.1, 2.2, 1.3, 2.3, 5.1, 5.4, 1.5, 4.5, 4.6 3.1, 3.2, 3.3, 4.4, 4.1 4.2 4.3 5.4, 7.6, 9.1, 11.1,
5.2, 6.2, 8.1, 8.2 6.1, 7.1, 7.6, 8.3, 5.3, 6.3, 7.1, 7.2, 7.4 11.2
9.1
General 7.1 X X X X X X X X
Preparation of concrete substrate
General 7.2.1 ISO 16311-3 X X X X X X
Cleaning 7.2.2 X X X X X X
Roughening 7.2.3  X X
Concrete removal 7.2.4 ISO 16311-3  X X
Preparation of reinforcement
General 7.3.1 ISO 16311-3  X X X
Cleaning 7.3.2 ISO 8501-1  X X X

7.2 Preparation of concrete
7.2.1 General
Weak, damaged and deteriorated concrete and, where necessary, sound concrete shall be removed in
accordance with the repair remedy and method chosen from ISO 16311-3.
If necessary, cleaning shall be carried out after roughening or concrete removal to comply with 7.2.2 unless
water-based methods are used, which can make this unnecessary.
Micro-cracked or delaminated concrete, including that caused by the techniques of cleaning, roughening,
or removal which reduces bond or structural integrity, shall be subsequently removed or remedied. The
finished surface shall be visually inspected and tested by tapping with a hammer to detect loose concrete.
7.2.2 Cleaning
For those methods which require cleaning, the following requirements shall be met:
a) the substrate shall be free from dust, loose material, surface contamination, and materials which reduce
bond or prevent suction or wetting by repair materials;
b) unless cleaning is carried out immediately before application of repair materials, the cleaned substrate
shall be protected from further contamination.
7.2.3 Roughening
For those methods which require roughening, the following requirement shall be met.
The texture of the roughened surface shall be appropriate for the products and systems to be applied and
shall be specified.
7.2.4 Concrete removal
For those methods which require the removal of concrete, the following requirements shall be met.
a) The extent of the removal shall be appropriate to the repair remedy and method chosen from those
given in ISO 16311-3.
b) Removal shall be kept to a minimum.
c) Removal shall not reduce structural integrity beyond the ability of the structure to perform its function.
Temporary shoring and bracing can be necessary.
d) The depth of carbonation and the concentration profiles of chloride or other contamination in the
concrete shall be established and taken into account.
e) The extent of the removal of the concrete shall be in accordance with the method chosen and shall be
specified. It shall take into account the following:
1) the penetration resistance of the concrete against gases and fluids;
2) the nature and concentration of the contamination before and after the repair and its anticipated
effect on the design service life of the repaired structure;
3) the depth of the contamination;
4) the depth of the carbonation;
5) the corrosion activity of the reinforcement;
6) cover to reinforcement;
7) the need for compaction of the repair material;
8) the need for bond to the substrate;
9) the need for treatment of reinforcement.
7.3 Preparation of reinforcement
7.3.1 General
Before repair systems are applied, the required condition of the existing and any new reinforcement shall
be prepared in accordance with the specification and the remedy and method chosen from ISO 16311-3,
and the required structural performance. The extent of any cleaning, coating, removal, or replacement shall
be specified taking into account the possible need for corrosion prevention and the need to provide the
specified bond between the repair products and systems and the reinforcement.
7.3.2 Cleaning
For those methods which require cleaning of the reinforcement, the following requirements shall be met.
a) Rust, scale, mortar, concrete, dust and other loose and deleterious material which reduce bond or
contribute to corrosion, shall be removed.
b) The whole circumference of the exposed reinforcement shall be uniformly cleaned, except where
structural considerations prevent it.
c) Unless the cleaning is carried out immediately before application of protection products and systems,
the cleaned substrates shall be protected against further contamination.
d) Reinforcement shall be cleaned without causing damage to it or damage to or contamination of the
adjacent concrete or environment.
e) Where exposed reinforcement is contaminated with chloride or other material which can cause
corrosion, the whole of the circumference of the contaminated reinforcement shall be cleaned by water
washing to remove the chlorides and other contaminants, unless electrochemical methods of repair are
to be used (see A.6.3).
f) For method 11.2 (given in Table 1), the degree of cleaning shall be to Sa 21/2 in accordance with
ISO 8501-1, or compliant with relevant standards and guideline in the area of use. For method 11.1 and
other methods, except method 11.2, where reinforcement is to be coated, the degree of cleaning shall
be specified and shall be suitable for the coating to be applied. The specification, method and choice of
cleaning shall take into account bar congestion, contact between bars, proximity to concrete substrate
and other factors which prevent access for cleaning (see A.6.3).
8 Application of products and systems
8.1 General
The application of the products and systems shall be suitable for the substrate and structure to which it
is applied and to produce repair which is in accordance with ISO 16311-2, ISO 16311-3 and ISO 22965-1,
ISO 22965-2 and ISO 22966.
Products shall be stored before use so that their properties shall not be impaired.
Access for the work shall be adequate so that products and systems can be prepared and applied in
accordance with this document.
Protection shall be provided so that preparation, application and subsequent curing shall be carried out in
accordance with this document.

Before and during application of the products and systems, the substrate temperature and moisture content,
and the characteristics of the environment, for example, temperature, relative humidity, dew point, rate of
change of moisture content, as influenced by precipitation and wind, shall be considered.
Mixing of products and systems shall be in accordance with ISO 22965-1, ISO 22965-2 and ISO 22966, or
shall be specified.
The thickness of layers of products and systems shall comply with this document or be specified.
The bond of the repair material with the substrate and between layers of repair material shall be not less
than the bond strength specified.
The requirements for application are given in the following subclauses and are related to the methods of
repair in Table 3.
Table 3 — Application of products and systems
Method no. in Table 1
Subclause no.
Hydrophobic Installing
Application (background
Filling cracks, Application Adding rein- Plate bond-
References
impregnation bonded rebars Coating rein-
process information
Surface coating voids or inter- of mortar and forcing steel ing and FRP
and impregna- in pre-formed forcement
in Annex A)
stices concrete bars strengthening
tion holes
1.1, 1.2, 2.1, 2.2, 1.3, 2.3, 5.1, 5.4, 1.5, 4.5, 4.6 3.1, 3.2, 3.3, 4.4, 4.1 4.2 4.3 5.4, 7.6, 9.1, 11.1,
5.2, 6.2, 8.1, 8.2 6.1, 7.1, 7.6, 8.3, 5.3, 6.3, 7.1, 7.2, 11.2
9.1 7.4
8.1 X X X X X X X X
Defects in concrete and structural strengthening
Bonding 8.2.1 ISO 22965-2 X X X X X
a a
Hand applied 8.2.2 ISO 22966 X X
mortar and con-
crete
a
Sprayed mortar 8.2.3  X
or concrete
a
Cast mortar or 8.2.4 ISO 22966  X
concrete
a
Curing 8.2.5 ISO 22966 X X
a
Cracks and joints 8.2.6 ISO 16311-3 X  X
a
Surface coatings 8.2.7 X X X
and hydrophobic
impregnation and
impregnation
Anchoring 8.2.8 ISO 22966  X X
Plate bonding and 8.2.9 ISO 8501-1   X
FRP Strength-
ening
Defects caused by reinforcement corrosion
Coating rein- 8.3.1   X X
forcement
Removal 8.3.2   X
Replacement 8.3.3 ISO 22966  X
ISO 9635-2
a
Where relevant.
8.2 Structural strengthening to restore member capacity — methods
8.2.1 Bonding
Bonding requirements shall be specified, and the applied mortar and concrete shal
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