ISO/FDIS 5091-2

Structural intervention of existing concrete structures using cementitious materials — Part 2: Top‐surface overlaying

Intervention structurelle sur les structures en béton existantes utilisant des matériaux cimentaires — Partie 2: Recouvrement de la surface supérieure

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 5091‐2
ISO/TC 71/SC 7 Secretariat: KATS
Voting begins on: Voting terminates on:
2022-07-20 2022-10-12
Structural intervention of existing concrete structures
using cementitious materials —
Part 2:
Top‐surface overlaying
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.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
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STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 5091-2:2022(E)
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. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/DIS 5091-2:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 5091‐2
ISO/TC 71/SC 7 Secretariat: KATS
Voting begins on: Voting terminates on:
Structural intervention of existing concrete structures
using cementitious materials —
Part 2:
Top‐surface overlaying
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

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on STANDARD UNTIL PUBLISHED AS SUCH.

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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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
Reference number
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 5091-2:2022(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 5091‐2:2022(E)
Contents Page

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

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

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

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

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

4 Investigation of existing structure...................................................................................................................................................3

4.1 General ........................................................................................................................................................................................................... 3

4.2 Investigation ............................................................................................................................................................................................. 3

4.2.1 Investigation using documents, records, etc. ........................................................................................... 3

4.2.2 On-site investigation ....................................................................................................................................................... 3

5 Intervention design........................................................................................................................................................................................... 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Structural plan ....................................................................................................................................................................................... 4

5.3 Structural details ................................................................................................................................................................................. 5

6 Materials ....................................................................................................................................................................................................................... 6

6.1 General ........................................................................................................................................................................................................... 6

6.2 Materials in existing structure ................................................................................................................................................ 6

6.3 Materials used in repairing or strengthening parts ............................................................................................. 6

6.3.1 Cementitious materials ................................................................................................................................................ 6

6.3.2 Reinforcing materials .................................................................................................................................................... 7

6.3.3 Bonding products .............................................................................................................................................................. 7

6.3.4 Waterproof materials ..................................................................................................................................................... 7

6.3.5 Pavement materials ......................................................................................................................................................... 7

6.4 Characteristic values and design values of materials for repaired or strengthened

parts ................................................................................................................................................................................................................. 7

6.4.1 General ........................................................................................................................................................................................ 7

6.4.2 Cementitious materials ................................................................................................................................................ 8

6.4.3 Reinforcing materials .................................................................................................................................................... 8

6.4.4 Bonding products .............................................................................................................................................................. 8

7 Actions ............................................................................................................................................................................................................................ 9

7.1 General ........................................................................................................................................................................................................... 9

7.2 Actions for intervention design ............................................................................................................................................... 9

8 Performance verification for repaired or strengthened structure ..............................................................9

8.1 General ........................................................................................................................................................................................................... 9

8.2 Calculation of response ................................................................................................................................................................ 10

8.2.1 General ..................................................................................................................................................................................... 10

8.2.2 Modeling of structure ................................................................................................................................................. 10

8.2.3 Structural analysis ........................................................................................................................................................ 10

8.2.4 Calculation of response values ........................................................................................................................... 10

8.3 Durability verification .................................................................................................................................................................. 10

8.3.1 General ..................................................................................................................................................................................... 10

8.3.2 Verification related to steel corrosion ......................................................................................................... 10

8.4 Safety verification ............................................................................................................................................................................ 11

8.4.1 General ..................................................................................................................................................................................... 11

8.4.2 Verification related to failure .............................................................................................................................. 11

8.4.3 Verification related to fatigue failure ........................................................................................................... 13

8.5 Serviceability verification ......................................................................................................................................................... 15

8.5.1 General .....................................................................................................................................................................................15

8.5.2 Stress level limit ............................................................................................................................................................... 15

8.5.3 Verification related to appearance .................................................................................................................. 15

8.6 Restorability verification ...........................................................................................................................................................15

iii
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ISO/DIS 5091‐2:2022(E)

8.6.1 General .....................................................................................................................................................................................15

8.6.2 Structural details related to seismic performance ...........................................................................15

8.7 Structural details .............................................................................................................................................................................. 15

8.7.1 Thickness of top-surface overlaying parts .............................................................................................. 15

8.7.2 Cover .......................................................................................................................................................................................... 16

8.7.3 Placement of reinforcing materials................................................................................................................. 16

8.7.4 Joints for reinforcing materials .......................................................................................................................... 16

9 Construction ..........................................................................................................................................................................................................17

9.1 General ........................................................................................................................................................................................................ 17

9.2 Prior investigation and construction plan.................................................................................................................. 18

9.3 Mix proportion of cementitious materials .................................................................................................................. 19

9.4 Preparation ............................................................................................................................................................................................. 19

9.5 Surface treatment ............................................................................................................................................................................. 20

9.6 Assembly of reinforcing materials ..................................................................................................................................... 20

9.7 Manufacture of cementitious materials ........................................................................................................................ 20

9.8 Transportation, placement, compaction and finish ............................................................................................ 20

9.9 Curing .......................................................................................................................................................................................................... 21

9.10 Pavement .................................................................................................................................................................................................. 21

9.11 Quality control ..................................................................................................................................................................................... 22

9.12 Inspection ................................................................................................................................................................................................22

10 Records ...................................................................... ..................................................................................................................................................23

11 Maintenance ..........................................................................................................................................................................................................23

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ISO/DIS 5091‐2:2022(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 5091‐2:2022(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 5091‐2:2022(E)
Structural intervention of existing concrete structures
using cementitious materials —
Part 2:
Top‐surface overlaying
1 Scope

These guidelines specify the standards for design and construction using the top-surface overlaying

method, which increases the thickness of existing concrete members by integrating cementitious

materials onto the top surface of the members so as to improve the safety, serviceability, durability

and other properties of a concrete structure. The requirements not mentioned in the Top-Surface

Overlaying section shall be as set forth in the ISO/NP 5091-1 and relevant standard specifications for

concrete structures.

NOTE Top-surface overlaying is a construction method that increases the thickness of existing concrete

members by placing and integrating cementitious materials onto the top surface of the members so as to improve

the safety, serviceability, durability and other properties of a concrete structure.

NOTE Typical structures to which top-surface overlaying is applied as an intervention method are highway

bridge reinforced concrete decks (hereinafter decks) that are subject to the repeated action of relatively large

variable loads. The method is mainly applied to improve the safety and other properties of decks that have

degraded due to fatigue resulting from the repeated action of traffic loads. It may also be applied to improve

durability and utility for such purposes as to respond to design load changes taking place as vehicles become

larger and protect the top surface of decks against degradation due to de-icing substance. Examples of applications

other than those for decks include overlaying reinforcement of the top surface of footings aimed at improving the

seismic performance of bridge piers whose existing footings have an insufficient flexural load-carrying capacity

for ground motions. While the Top-Surface Overlaying section is not necessarily confined to a specific type of

structure, it mainly covers the standard design and construction methods for top-surface overlaying of decks.

NOTE For top-surface overlaying to produce the specified effect, it is indispensable to integrate the existing

members with the cementitious materials of the overlaying parts. In some cases, after the top surface of decks

is cut and cleaned, fiber-reinforced concrete is placed while adhesive is applied in order to achieve integrity. The

primary reason for using fiber-reinforced concrete on the overlaying parts is to improve the flexural resistance,

tensile resistance, shear resistance and cracking resistance of the concrete. For example, since the cross-section

layer of the top-surface overlaying parts is relatively thin, there is possibility of cracking occurring due to initial

drying or occurring and progressing due to active loads. Mixing fiber is expected to suppress the progress of

cracking. Also, in intermediate support points and overhanging decks of continuous girder bridges, reinforcing

materials such as reinforcing steel and FRP reinforcing materials are used to improve the negative flexural load-

carrying capacity. In top-surface overlaying for footings, the thickness is greater than for decks. In the case of

mass concrete, therefore, a measure needs to be taken to protect against thermal cracking due to hydration heat

of cement.

NOTE These guidelines describe a specific method of verifying the performance of a structure repaired

or strengthened by means of top-surface overlaying based on the currently available latest technologies. Note,

however, that the verification method described herein does not cover all kinds of verification. For necessary

information, reference shall be made to the relevant standard specifications and other documents. In the future,

as purposes for intervention, diversify and advances in technology are made, many different methods are

expected to be proposed.
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ISO/DIS 5091‐2:2022(E)

NOTE Given that members subject to intervention are mostly decks at present, the standard methods are

described herein that are considered the latest information on design and construction of top-surface overlaying

using fiber-reinforced concrete on overlaying parts. As technology advances, new materials and design and

construction methods are developed and methods for evaluating the post-intervention structural performance

with sufficient accuracy are established, making it possible to apply top-surface overlaying for intervention parts

and members other than decks, use materials other than fiber-reinforced concrete, employ interface treatment

methods other than cutting, cleaning and adhesive, etc., it is not necessarily required to adhere to what is set

forth in these guidelines.
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
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
General

The definitions of the terms used in the Top-surface overlaying section shall be as defined in Clause 3 of

ISO / NP 5091-1.
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ISO/DIS 5091‐2:2022(E)
4 Investigation of existing structure
4.1 General

The investigation of the existing structure for intervention using the top-surface overlaying method

shall be as set forth in Clause 4 of the ISO/NP 5091-1.

NOTE Intervention using the top-surface overlaying method needs to be designed by understanding

the condition of the existing structure through a prior investigation, and plans for construction, construction

management and inspections need to be formulated based on the results of the design. The investigation of

the existing structure shall be as set forth in Clause 4 of the ISO/NP 5091-1 and involve an investigation using

documents, records, etc. and an on-site investigation. It is necessary to check the condition of the structure,

environmental conditions and conditions of use, as well as to understand the restrictions and problems on

intervention, through these studies.
4.2 Investigation
4.2.1 Investigation using documents, records, etc.

The investigation of the existing structure using documents, records, etc. for top-surface overlaying

shall be as set forth in Clause 4 of the ISO/NP 5091-1.

NOTE To check the performance that the existing structure possesses, it is necessary to understand such

information as the dimensions of members, steel arrangement and materials us
...