ISO/FDIS 5091-1

Structural intervention of existing concrete structures using cementitious materials — Part 1: General principles

Intervention structurelle sur les structures en béton existantes utilisant des matériaux cimentaires — Partie 1: Principes généraux

General Information

• Status: Not Published
• ICS: 91.080.40 - Concrete structures
• Technical Committee: ISO/TC 71/SC 7 - Maintenance and repair of concrete structures
• Drafting Committee: ISO/TC 71/SC 7 - Maintenance and repair of concrete structures
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 26-Apr-2023
• Completion Date: 26-Apr-2023

Standards Content (Sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 5091-1
ISO/TC 71/SC 7 Secretariat: KATS
Voting begins on: Voting terminates on:
2022-07-18 2022-10-10
Structural intervention of existing concrete structures
using cementitious materials —
Part 1:
General principles
ICS: 91.080.40
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
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NATIONAL REGULATIONS.
ISO/DIS 5091-1:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
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ISO/DIS 5091-1:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 5091-1
ISO/TC 71/SC 7 Secretariat: KATS
Voting begins on: Voting terminates on:
Structural intervention of existing concrete structures
using cementitious materials —
Part 1:
General principles
ICS: 91.080.40
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2022
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

NOT BE REFERRED TO AS AN INTERNATIONAL

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the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

IN ADDITION TO THEIR EVALUATION AS

or ISO’s member body in the country of the requester. BEING ACCEPTABLE FOR INDUSTRIAL,

TECHNOLOGICAL, COMMERCIAL AND
ISO copyright office
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STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
CH-1214 Vernier, Geneva
POTENTIAL TO BECOME STANDARDS TO
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WHICH REFERENCE MAY BE MADE IN
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 5091-1:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
Published in Switzerland
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
© ISO 2022 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
---------------------- Page: 2 ----------------------
ISO/DIS 5091-1:2022(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 2

4 Investigation of existing structure...................................................................................................................................................4

4.1 General ........................................................................................................................................................................................................... 4

4.2 Investigation ............................................................................................................................................................................................. 4

4.2.1 Investigation using documents, records, etc. ........................................................................................... 4

4.2.2 On-site investigation ....................................................................................................................................................... 4

5 Intervention design........................................................................................................................................................................................... 5

5.1 General ........................................................................................................................................................................................................... 5

5.2 Structural plan ....................................................................................................................................................................................... 5

5.3 Structural details ................................................................................................................................................................................. 6

6 Materials ....................................................................................................................................................................................................................... 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 Materials in existing structure ................................................................................................................................................ 7

6.3 Materials used in repairing or strengthening parts ............................................................................................. 8

6.3.1 General ........................................................................................................................................................................................ 8

6.3.2 Cementitious materials ................................................................................................................................................ 8

6.3.3 Reinforcing materials .................................................................................................................................................... 9

6.3.4 Filling materials ............................................................................................................................................................... 10

6.3.5 Bonding products ........................................................................................................................................................... 10

6.4 Characteristic values and design values of materials ...................................................................................... 11

6.4.1 General ..................................................................................................................................................................................... 11

6.4.2 Cementitious materials ............................................................................................................................................. 11

6.4.3 Reinforcing materials .................................................................................................................................................13

6.4.4 Bonding products ........................................................................................................................................................... 14

7 Actions .........................................................................................................................................................................................................................14

7.1 General ........................................................................................................................................................................................................ 14

7.2 Actions for intervention design ............................................................................................................................................15

8 Performance verification for repaired or strengthened structure ...........................................................15

8.1 General ........................................................................................................................................................................................................ 15

8.2 Calculation of response values .............................................................................................................................................. 16

8.2.1 General ..................................................................................................................................................................................... 16

8.2.2 Modeling ................................................................................................................................................................................. 17

8.2.3 Structural analysis ........................................................................................................................................................ 17

8.2.4 Calculation of response values ........................................................................................................................... 18

8.3 Durability verification .................................................................................................................................................................. 18

8.3.1 General ..................................................................................................................................................................................... 18

8.3.2 Verification related to steel corrosion ......................................................................................................... 19

8.3.3 Verification related to degradation of cementitious materials..............................................20

8.4 Safety verification ............................................................................................................................................................................ 20

8.4.1 General .....................................................................................................................................................................................20

8.4.2 Verification related to failure .............................................................................................................................. 21

8.4.3 Verification related to fatigue failure ........................................................................................................... 22

8.5 Serviceability verification ......................................................................................................................................................... 23

8.5.1 General .....................................................................................................................................................................................23

8.5.2 Stress level limit ............................................................................................................................................................... 23

8.5.3 Verification related to appearance .................................................................................................................. 23

8.5.4 Verification related to vibration ........................................................................................................................ 24

iii
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ISO/DIS 5091-1:2022(E)

8.5.5 Verification related to water-tightness ....................................................................................................... 24

8.6 Restorability verification ........................................................................................................................................................... 24

8.6.1 General ..................................................................................................................................................................................... 24

8.6.2 Structural details related to seismic performance ........................................................................... 25

8.7 Structural details .............................................................................................................................................................................. 25

9 Execution ...................................................................................................................................................................................................................25

9.1 General ........................................................................................................................................................................................................ 25

9.2 Construction plan ............................................................................................................................................................................. 25

9.3 Construction .......................................................................................................................................................................................... 26

9.4 Inspection ................................................................................................................................................................................................ 26

10 Records ...................................................................... ..................................................................................................................................................26

11 Maintenance ..........................................................................................................................................................................................................27

Annex A (informative) Examples of test and design method ..................................................................................................28

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ISO/DIS 5091-1:2022(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

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)

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

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 Organisation (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.

A list of all parts in the ISO 5091 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.
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ISO/DIS 5091-1:2022(E)
Introduction

As a repairing and strengthening method, attaching of cementitious material layer to surface of

existing concrete structures has been widely accepted. Since the cementitious layer does not have

enough tensile strength, tension reinforcement is generally placed in the cementitious layer. There are

two types of attaching way. For the first way, the cementitious layer is attached either on top surface

or bottom surface of horizontal concrete members, especially slabs, while, for the second way, the

cementitious layer is attached to jacket vertical concrete members, especially columns. There has not

been ISO standard on design, execution and maintenance for this method with attaching cementitious

layer. This ISO 5091 serves as the first ISO standard for the intervention by attaching cementitious

material layer with tension reinforcement inside.

At the same time, this ISO 5091 is the first ISO standard developed for a specific intervention method,

which conforms to the umbrella code, ISO 16311 Maintenance and repair of concrete structures,

especially ISO 16311-3 – Part 3: Design of repairs and prevention and ISO 16311-4 – Part 4: Execution of

repairs and prevention.

ISO 5091 Structural intervention of existing concrete structures using cementitious materials consists

of four parts; ISO 5091-1 – Part 1: General principles, ISO 5091-2 – Part 2: Top-surface overlaying,

ISO 5091-3 – Part 3: Bottom-surface (soffit) underlaying, and ISO 5091-4 – Part 4: Jacketing. ISO 5091-1

provides the issues common to all three parts, while ISO 5091-2, 3 and 4 provide the issues specific to

each attaching way of cementitious material layers.

It is expected that this ISO 5091 could serve as a practical standard for construction industry, such as

client, design consultant and general contractor, to apply the structural intervention with externally

attached cementitious layer. Additional technical information, which is not provided explicitly in

ISO 5091, needs to be provided in each application case with consideration of the provisions of ISO 5091.

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DRAFT INTERNATIONAL STANDARD ISO/DIS 5091-1:2022(E)
Structural intervention of existing concrete structures
using cementitious materials —
Part 1:
General principles
1 Scope

This document specifies the standards for design, construction and maintenance following completion

of intervention that is to be applied for performing intervention work using cementitious materials to

improve the performance of existing concrete structures. The intervention dealt with in this guideline

is intended to restore, sustain or improve the mechanical performance of concrete structures. When

the intervention is aimed at restoring or improving durability, reference should be made to relevant

documents.

This document covers the overlaying, underlaying and jacketing methods using cementitious materials.

Assuming that the standard requirements regarding the intervention of existing structures are as

set forth in ISO 16311, especially Parts 3 and 4, this document consists of Part 1: General principles

specifying the common requirements not dependent on the method of performing intervention using

cementitious materials and method-specific Parts 2, 3, and 4, each describing the specifics of top-

surface overlaying, bottom-surface (soffit) underlaying and jacketing, respectively.

The intervention with cementitious materials shallis covered in Clause 4 Basis of maintenance and

repair of ISO 16311-1.
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 16311-1:2014, Maintenance and repair of concrete structures — Part 1: General principles

ISO 16311-2:2014, 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 16311-4:2014, Maintenance and repair of concrete structures — Part 4: Execution of repairs and

prevention

ISO 19338:2014, Performance and assessment requirements for design standards on structural concrete

ISO 1920-8, Testing of concrete — Part 8: Determination of drying shrinkage of concrete for samples

prepared in the field or in the laboratory

ISO 10406-2, Fibre-reinforced polymer (FRP) reinforcement of concrete — Test methods — Part 2: FRP

sheets

ISO 10406-3, Fibre-reinforced polymer (FRP) reinforcement of concrete — Test methods — Part 3: CFRP

strips
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ISO/DIS 5091-1:2022(E)
ISO 12473, General principles of cathodic protection in seawater
ISO 13823, General principles on the design of structures for durability

ISO 14484, Performance guidelines for design of concrete structures using fibre-reinforced polymer (FRP)

materials
ISO 22966, Execution of concrete structures
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
Top-surface overlaying

A method in which the thickness of the structural element associated with the top surface of the existing

concrete members is increased using cementitious materials, which will generally be reinforced. The

technique enhances the performance (e.g. strength, stiffness) of the existing concrete structure and is

applicable to highway bridge decks, etc.
3.2
Bottom-surface (soffit) underlaying

A method in which the thickness of the structural element associated with the bottom surface of the

existing concrete is increased using cementitious materials, which will generally be reinforced. The

technique enhances the performance (e.g. strength, stiffness) of the existing concrete structure and is

applicable to highway bridge decks, tunnel linings, box culverts / waterway structures, beams, etc.

3.3
Jacketing

A method in which additional cementitious materials and associated reinforcement are added to the

periphery of the existing concrete member to increase its strength, stiffness and/or ductility (applicable

to columns, bridge piers, rigid-frame pier beams, etc.)
3.4
thickening capability

ability to achieve the required application thickness of one layer of polymer hydraulic cement mortar or

other mortar material
3.55
bonding product

material, such as a primer, anchor grouting material or adhesive, that is applied or grouted to bond

concrete members, concrete and mortar or concrete and reinforcing material
3.6
filling material

material injected to fill the gap between a reinforcing material, such as intermediate penetrating tie,

and concrete
3.7
filling property
degree of filling of cracks and adhesion of crack filling material to substrate
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ISO/DIS 5091-1:2022(E)
3.8
intermediate penetrating tie

reinforcing member, generally made of steel or FRP, that is installed inside the drilled hole and glued

into the concrete substrate to improve the ductility and shear strength of bridge piers

3.9
very high early strength cement

type of cement with a typical mix proportion that develops a compressive strength as high as 20 N/

2 2
mm to 30 N/mm within 2 to 3 hours of placement
3.10
reinforcing material

steel or FRP reinforcing material used to sustain the performance of a structure or to restore or

improve performance
3.11
polymer hydraulic cement mortar
hydraulic mortar modified by the addition of a polymer
3.12
overlaying or underlaying material

cementitious material, potentially reinforced, added to an existing concrete structure for the purpose

of making an intervention to enhance the performance of that structure

Note 1 to entry: The top-surface overlay / bottom-surface (soffit) underlay shall achieve adequate bond to the

existing concrete substrate.
3.13
FRP grid
resin-impregnated FRP reinforcing materials formed into a grid shape
3.14
design response value

value of structural response obtained by numerical analysis on design process, such as sectional force

and deformation
3.15
design limit value

design value for quantified limit state on design process, such as strength of element, allowable crack

width
3.16
verification index

representative items to be quantitatively verified by design response value and design limit value on

design process, such as deflection, crack width and strength
3.17
cross section failure

failure which is related to cross sectional strength, such as flexure, shear and axial strength

3.18
maintainability

ability of a structure to meet service objectives with a minimum expenditure of maintenance effort

under service conditions in which maintenance and repair are performed
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ISO/DIS 5091-1:2022(E)
4 Investigation of existing structure
4.1 General

The existing structure for which intervention is to be considered shall be investigated in detail to

obtain the information necessary for intervention design and construction.
4.2 Investigation
4.2.1 Investigation using documents, records, etc.

When an investigation is conducted using documents, records, etc., the climatic conditions,

environmental conditions, geographical conditions and other relevant conditions of the local site shall

be understood in detail from the following viewpoints:
— formulation of material and structural plans;
— formulation of a construction plan; and
— maintenance following completion of intervention.

NOTE Generally, the workability and hardening characteristics of cementitious materials greatly change

depending on the construction environment, such as temperature and, therefore, it is necessary to see the

climate of the local site during the period when construction is planned to be performed. Also, intervention using

cementitious materials requires that the restrictions of the local site regarding the construction space as well

as the carry-in and installation of materials and equipment be understood before a specific construction plan is

formulated.
4.2.2 On-site investigation

On the site, an investigation shall be conducted to check degradation, damage and initial defects of the

existing concrete structure from the following viewpoints:
— Securing of integrity between the existing parts and strengthening parts
— Prediction of durability and degradation after intervention

NOTE In obtaining the expected effect of intervention using cementitious materials, integrity between

the repairing or strengthening parts and existing structure is important. Ensuring integrity requires taking

necessary measures based on the understanding of degradation, such as carbonation of the surface of the

existing structure, damage such as cracks, splash or leakage of water, etc.

Degradation of a concrete structure after intervention progresses at a different rate depending on the type of

cause and degree of degradation. Therefore, before intervention is performed for a damaged concrete structure,

it is necessary to understand the cause and degree of degradation.
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ISO/DIS 5091-1:2022(E)
5 Intervention design
5.1 General

In intervention, a rational structural plan shall be formulated and structural details shall be established

based on that plan so that the structure after intervention fulfills the required performance throughout

the remaining design service life.

NOTE The intervention design involves establishing a structural plan and structural details to ensure that

interve
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