the importance of the european standard en 1504, on the
TRANSCRIPT
RESEARCH ARTICLE
The importance of the European standard EN 1504,on the protection and repair of concrete structures
F. C. B. Monteiro1 • L. M. Trautwein1 • L. C. Almeida1
Received: 29 June 2016 / Accepted: 5 January 2017 / Published online: 18 January 2017
� Springer International Publishing Switzerland 2017
Abstract The growing concern for sustainability in con-
struction, supported by environmental policies, has been
urging the designers, builders and entities linked to the
sector, a more informed view of the importance of the
aspects that relate to the quality, performance, durability
and life useful constructions, translated into a set of pro-
cedures, obtained by the technical/scientific experiment
and research, giving rise to Normative documents or
Guidelines that regulate the practice of construction. The
above, the present study aims to highlight the importance
of European Standard EN 1504, entitled: ‘‘Products and
systems for the protection and repair of concrete struc-
tures’’, both present as a single document that includes all
aspects that relate to the protection of processes and/or
repair, as well as leads to an absolute involvement of all
professionals affects the work (owners of the works,
designer, contractors and suppliers material). This fact has
allowed a higher level of confidence of project owners and
simultaneously obtaining quality construction and superior
durability. The standard content comprises 10 distinct
parts. Initially, there will be a theoretical approach of each
party, follows the relationship between them and finally
their practical applicability through four concrete exam-
ples. Thus, it intends to contribute with the professional
progress, in the use of this powerful wide application tool,
from simple detection of pathologies arising from the
development and repair of project control.
Keywords EN 1504 � Recommendations �Standardization � Repair
1 Scenario
Beyond the already known natural deterioration causes
(mechanical, physical, chemical and biological), as well as
human failures (reflected in project flaws, inadequate use of
construction materials, failures during the construction and
the inexistence of efficient maintenance, etc.) [1], there are
different factors, such as: economic speculation of real
estate costs and the lack of thoroughness concerning pro-
fessionals and companies pressured by strong competition,
the growing environmental pollution, among others; that
aggravating along the last decades have led respectively to
structures slimmer and less prepared to certain pathological
agents. As a consequence, several years after the big
‘‘boom’’ of the use of concrete in construction, a growing
aging on structures, full of anomalies, that brings a
necessity of preservation of the built patrimony is
observed. Thus it is urgent the development of techniques
and material that aim to improve reinforced concrete
structures with original, mechanical, functional and aes-
thetics characteristics and also extend their lifetime cycle.
It is notorious the increasing worry of governmental enti-
ties in legislating the civil construction sector, in a way to
create standardization of constructive aspects to guarantee
quality, performance and durability of constructions. On
the other hand, construction companies facing the new
realities, seek to adapt with the conscience that their
presence in the market increasingly demands an image
& F. C. B. Monteiro
L. M. Trautwein
L. C. Almeida
1 Civil Engineering, Universidade Estadual de Campinas-FEC,
Sao Paulo, Brazil
123
J Build Rehabil (2017) 2:3
https://doi.org/10.1007/s41024-017-0022-0
characterized by strictness and obedience to current legis-
lation. In this scenario, this work aims at presenting per-
tinent specifications to reach the durability presented on the
document EN 1504.
2 The evolution of the concrete structuresdurability concept
According to [2], concrete constructions were guided by
good sense and professional experience until the eighties,
being the most important requirement for security the
medium resistance to compression. With knowledge evo-
lution, mainly regarding the transportation of liquid and
aggressive gases through porous environments (concrete),
possible consequences of synergy in different degradation
processes [3], it was possible to associate the time factor to
mathematical models that express these mechanisms in
numbers, which contributed significantly to expressing the
lifetime evaluation in years and not in structure adequacy
to certain degrees of environmental exposition criteria.
Consequently, durability ceased being a subjective aspect,
exclusively ensured by prescriptive requirements, and gave
place to one of the most important project demands.
On the other side, norms and technical documents from
diverse entities (national and international), elaborated in
the last three decades, contributed a lot to the expansion
and consolidation of the knowledge in favor of the dura-
bility and increasing lifetime of concrete structures. For
these reasons and considering factors of competitiveness,
costs and environment preservation, it is possible to
observe the current worldwide tendency, of prioritizing the
project aspects based on the requirements previously
focused, demanding multidisciplinary teams acting in
every step of the constructive process and mainly master-
ing the phenomena or physicochemical and mechanical
processes and its synergies.
3 Regulations
3.1 Concept and objectives: standardization
organizations (committees)
According to [4], the increasing competitiveness, the
globalized market demands and societies needs, require
from organizations the adoption of optimized management
methods, that depend on the capacity of incorporating new
products and process technologies. This context directs
companies to the use of standards in a way that they rep-
resent a management instrument that facilitates access to
markets. To that extent, standardizing came to regulate and
improve products, process and services adequacy to the
purpose they were designed, increasing in this way, the
acceptability from markets through references of the stan-
dardized methods. Parallel to this, it also contributed to the
optimization of the companies’ management and service
rendering, consequently diminishing inherent costs. It is
possible to say that, the standards propitiate the correct
supply for practical requirements from producers and
consumers and are fundamental to eliminate the waste of
time, raw material and work force, resulting in market
growth, quality improvement and price and costs reduction,
factors that feed the social development engine cycle.
Succinctly, Standardization is developed in diverse
levels through international standardization organizations
(ISO), regional (CEN—European standardization organi-
zation) and nationals (ONN—national standardisation
organisation, for example: ANSI (American national
standards institute), BSI (British standards institution),
AFNOR (Association Francaise de normalisation), ABNT
(Associacao Brasileira de normas tecnicas), IPQ (Instituto
Portugues da qualidade), AENOR (Asociacion Espanola de
normalizacion y certificacion), UNI (Ente nazionale Ital-
iano di unificazione), DIN (Deutsches institut fur
Normung).
3.2 Main European standards applicable
to the project and concrete structures execution
3.2.1 Standards evolution; European standards
transposition for Portuguese regulation
To regulate the construction activity that involves the use
of ‘‘concrete’’, Europe named since the eighties a work
group TC 104 from CEN (European standardization com-
mittee), composed by several subcommittee, destined to
elaborate a series of specific standards referred to the ele-
ment ‘‘concrete’’. From the numerous subcommittees, the
SC1 is evidenced, destined to emit and review the Euro-
pean Provisory Standard ENV 206: 1990, ‘‘Concrete –
Behaviour, production, placement and conformity crite-
ria’’, aiming to regulate and standardize the fabrication and
application of concrete, based on the presumptions of
durability. These new standards, already present them-
selves more consistent than the previous as they present a
higher dominium of the main factors that intervene in
concrete durability. In the nineties a set of standards were
published, nine Eurocodes, for the use in project of dif-
ferent materials, highlighting the Standard EN 1992:
‘‘Design of concrete structures’’ [5], that absorbs and
consolidate all aspects referring to the application of con-
crete properties, contained in the European Pre-Standard
ENV 206: 1990.
The new regulatory framework of the material ‘‘concrete’’
substantiated by the Standard EN 206-1: 2005 ‘‘Concrete -
3 Page 2 of 12 J Build Rehabil (2017) 2:3
123
Specification, Performance, Production and Conformity’’ [6].
The prevision of the present standard considers the techno-
logical evolutions related to the production aspects, the
durability of the structures and the testing methodologies.
However, the most significant alterations are in the classifi-
cation of environmental actions and in the requirements of the
concrete inserted in aggressive environments; in the use of
additives to substitute part of the concrete and in production
control, including conformity control. On the other hand, all
matters related to the execution in work, that is, placing,
compacting and curing, were removed from the original ENV
206 and remitted to theEuropeanPre-StandardENV13670-1:
2000 ‘‘Execution of concrete structures’’, that upon updates,
prevails through the European Standard EN 13670: 2009 [7].
The European Standard EN 206-1: 2005 [6], according to
the insertion of the work in the environment, it is imposed to
the designer the necessity of knowing, evaluating and clas-
sifying the degree of environment aggression that the
structure of reinforced concrete is exposed, so that based in
this classification, it is possible to define the type of cement
(including additives), the concrete minimum resistance cat-
egory, the minimum dosage of concrete, the maximum ratio
water/cement, the minimum nominal covering, the maxi-
mum dimension of the aggregate, the category level of
chlorides, the eventual use of additives (adjuvant), and the
consistence class. All of these criteria are similar to the
Brazilian standard ABNT NBR 6118 [8], that varies
according to the environmental aggression class (classified
by the pathological local agents) and the nature and char-
acteristics of the concrete to project. Fulfilling all these
requirements, it is expected that the structure during its
project useful life (from 50 to 100 years, according to the
pre-established category), can support with appropriate level
of reliability and in an economical way all actions (being
mechanical or environmental), during its use and operation
and continue adequate to the function that it was conceived.
In Portugal, the transposition of European standards into
updated national standards occurred according to Fig. 1,
and it is possible to observe the relationship between
standards NP EN 206-1: 2007 (concrete standard) [6], NP
EN 1992: 2010 (design standard) [5], and NP EN 13670:
2010 (works executions standard) [7].
3.3 European standard applicable
to the rehabilitation of concrete structures
3.3.1 Presentation of the European standard EN 1504;
objectives and organization. The Portuguese
standard NP EN 1504
From the work group TC 104 from CEN (European Com-
mittee of Standardization) previously mentioned, the sub-
committee 8 (SC8) is highlighted, in charge of working on
preparing a series of specific standards for repairing and
protection of concrete structures, including definitions, prod-
ucts requirements, references and testing methods, quality
control and verification of conformity. In 2009 the European
Standard EN 1504:2009 was emitted, entitled ‘‘Products and
Systems for Reparation and Protection of Concrete Struc-
tures’’, aimed at definingproducts andmethods, requirements,
quality control and evaluation of conformity and specifica-
tions referring to their applications. In addition to the above,
the standard attributes responsibilities to all participants
concerning the construction/reparation activities according to
their performance, as well as predicts the technical control of
reparation and protection of concrete that circulates on the
European area through CE marking system that includes the
register of all required and obtained characteristics by stan-
dardized tests (EN 1505-2). This project required a
notable technological advancement, related to the technical
performance requisites of concrete reparation and protection
products, from the manufacture of construction material
industry. The existence of classification models provided on
the Standard, permitted suppliers to catalog their products due
to its characteristics and to the functions they are destined to.
Thereby, without error rates, it is possible to say that this
regulation represents the culminating ofmore than 15 years of
work of professionals from all industry quarters of concrete
reparation. It is undoubtedly a resource that helps designers,
building contractors, manufacturing companies and guaran-
tees the satisfaction and the confidence of proprietors.
Transposed to the Portuguese Standard, the NP EN 1504,
presents 10 distinct parts, according to its functions: (Fig. 2).
Figure 2, adapted from [10], describes the organization
chart of the NP EN 1504, showing it’s diferentes parts and
the relationship between them. According to [6], the 10
parts that constitute the standard are associated to about 65
different standards, corresponding to the tests that refer to
the requisites of identification and performance of products
and systems and to the control of its quality and to the
evaluation of its conformity. Figure 2 illustrates the inter-
connection among the various parts of the standard.
Part 1 from NP EN 1504 contemplates the definitions of
all terms applied to the totality of the parts and defines the
main categories of products and systems, as well as all
types of chemicals and main constituents of them.
Parts 2 and 7 also constitute the series core, referring to
the requirements of identification and performance of the
types of systems and products contemplated in the stan-
dard, and the testing methods associated to them.
Part 8 summarizes all procedures for the quality control,
based on EN ISO 9001, and the evaluation of conformity of
products and systems envisaged in the series NP EN 1504,
contemplating its marking ‘‘CE’’ and its label, according to
a group of specific tests. It is destined to the manufacturer
and the Certification Institute.
J Build Rehabil (2017) 2:3 Page 3 of 12 3
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Part 9 corresponds to the general application and principles
to the use of the products and systems defined in parts 2 to 7.
Part 10, refers to the application at the local of the
materials and to the applications quality control.
3.3.2 Phases of a reparation project: NP EN 1504-9
If there is need to carry out a repair project, the Standard
NP EN 1504 guides, proposing in a flexible way the fol-
lowing project phases, subdivided into six subchapters:
• Information about structure.
(Through project pieces, maintenance plan, site condi-
tions and others).
• Evaluation process.
(It has to include: visible structure state; test that permits
to determine the concrete and reinforcement state;
anomalies map; original project concession; character-
ization of environmental exposition condition; existing
condition during construction, including climate condi-
tions, material used such as the nature of the mixing
water, types of aggregated, etc; history of structure in
terms of actions and type of utilization of the structure;
definition of requirements for structure future use, etc.)
• Management strategy.
(The life cycle of the project after repairing interven-
tion is fundamental when choosing the management
strategy. The interventions can be of exhaustive and
maintenance type. According to the standard, the
appropriate choice for repairing must consider the
following management options: do not intervene but
monitor; review the structure capacity that may lead to
a change in operation; prevent or reduce other deteri-
oration; reinforcing or repairing and protect all or part
of the concrete structure; reconstruct or substitute all or
part of the concrete structure; demolish all or part of the
concrete structure. Another important aspect that the
standard adds is the specification of the factors to
consider upon choosing the repairing method. The
strategy choice of management is not restricted to the
technical slope. It must involve other factors analysis,
such as: economical, functional, environmental, and the
future requirements intended by the owner of the
DL 301-2007
Concrete Structures
Project EN 1992
Concrete EN 206-1
Execu�on EN 13670-1
19731NE Evalua�on of
concrete resistance in
structures
CONSTITUENTS
EN 197 Cement EN 450 Fly Ashes EN 13262 Silica Fume EN 12878 Pigments EN 934-2 Adjuvant EN 12620 Aggregates EN 13055-1 Lightweight aggregates EN 1008 Mixing water
TESTS EN 12350 Fresh concrete
EN 12360 Hardened concrete
EN 12504 Tests in-situ
EN 12504 Tests in-situ
Fig. 1 European standards transposition for Portuguese regulation. (Adapted from [9])
3 Page 4 of 12 J Build Rehabil (2017) 2:3
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building, (that is, factors of: base, structural, health/
safety and environmental).
• Project of repairing work.
(The type phases proposed by the standard are: collect the
data resulting of the process of evaluation and of the
strategyofmanagement; analysis of the repairingprinciples
applicable; choice of methods for protection and repair of
the structure; analysis of possible unwanted consequences
resulting of the application of one or more methods in the
individual specific conditions; definition of the products
and systems specifications correspondents to the methods
of repair adopted, basedon the requirementsdefined inparts
2 to7ofNPEN1504; executionof structural analysis andof
security after the protection and the repair).
• Repair work.
(The works execution method is determinant part in the
complex process of protection and repair of reinforced
concrete. The part 10 of NP EN 1504 this way defines
the requirement of the substrate before and during
application, including structural stability of the studied
elements, preparation and application of products and
systems of repair, quality control of the work done,
security, health and environment. In general, the NP EN
1504-10 Standard defines for each repairing method
three process phases: substrate preparation; application
of products and systems; quality control. The quality
control of the repairing works is done through tests or
observations, according to the used method. The
Standard provides a framework with a summary of
the tests and observations to perform, that are subdi-
vided in four phases: conditions of the substrate before
or after preparation; acceptance of products and
systems; conditions and requirements before or during
application; and final condition of the hardening. For
each one of the forty five tests and observations, the
appendix A of NP EN 1504-10 specific to the EN
NP 1504-1: Defini�ons
NP 1504-2: Systems of superficial protec�on
of concrete
NP 1504-10: Applica�on of products and systems and control of quality of
the work
NP 1504-9: General principles for the use of products and systems
NP 1504-3: Structural and non-structural
repara�on
NP 1504-4: structural bonding
NP 1504-4: Structural bonding
NP 1504-6: Anchoring of reinforcing steel bar
NP 1504-7: Protec�on against reinforcement
corrosion
Tes�ng methods
NP 1504-8: Quality control and conformity evalua�on
NP 1504-5: Concrete injec�on
Fig. 2 Interconnection among different parts of the NP EN 1504.
(Adapted from [10]). NP 1504-1 describes the terms and definitions in
the Standard, NP 1504-2 provides specifications to products/systems
of superficial protection of concrete, NP 1504-3 provides specifica-
tions/requisites to the structural and non-structural reparation, NP
1504-4 provides specifications/requisites to structural bonding, NP
1504-5 provides specifications/requisites to concrete injections, NP
1504-6 provides specifications/requisites to anchoring of reinforcing
steel bars, NP 1504-7 provides specifications/requisites to the
anticorrosive protection of the reinforcement, NP 1504-8 describes
the quality control and evaluation of conformity of products and
systems provided in the series NP EN 1504, contemplating its ‘‘CE’’
marking and label, NP 1504-9 define the general principles for the
utilization of products and systems in reparation and protection of the
concrete, NP 1504-10 provides information about the application of
products in work and their quality control
J Build Rehabil (2017) 2:3 Page 5 of 12 3
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Standard, national standards or ISO to use for its
execution, also giving orientation on the maximums
and minimums acceptable parameters to the character-
istics tests).
• Acceptance of repair work.
After repair work finish and always when applicable, a
management system of maintenance must be imple-
mented to guarantee the lifetime of the interventions. In
cases where the integrity of the structure directly depends
of the products and systems good condition, thesemust be
regularly inspected, tested and renewed if necessary.
Thus, the constructor proprietor must keep all registers of
utilized material and respective application method, and
also future interventions to perform in the ambit of
inspection and maintenance, the inherent risks of deteri-
oration of the performed works and the structure lifetime.
3.3.3 Principles and methods of protection and repair: NP
EN 1504-9
According to Tables 1 and 2, the series NP EN 1504 estab-
lishes 40 methods of repair, grouped in 11 principles that
enable the prevention of causes of physical, chemical and
electrochemical deterioration, that emerge in concrete and in
reinforcements. Six of these principles are related to the
defects of the concrete and five to the corrosion of the rein-
forcement. To each principle various methods are associated
and for each method it is possible to adequate products or
systems. The systems arise from the conjugation of two or
more products applied in a successive or combined form. The
principles followed by the Standard comprise already known
causes: human actions, mechanicals, physicals, and chemi-
cals P (1–6) and electrochemical actions P (7–11).
3.3.4 General considerations on the execution of the works
and the quality control: NP EN 1504-8; NP EN
1504-10
Once the management strategy is defined, follows the
realization of the repair work project, based on the main
project stages: (choice of the methods and principles of
repair based on the elements collected; analysis of the
compatibility of the methods and of viability conditions;
definition of the products and systems to apply according to
the principles and methods adopted and of the economic
analysis; evaluation of the results on the structure inter-
vention). The products and systems specifications corre-
spondent to the methods of repair adopted are defined on
the characteristics of performance contained in the charts
of parts 2 and 7 of the Standard NP EN 1504.
About the work execution, the Standard foresees funda-
mentally three phases: preparation of the substrate (concrete
cleaning, adherence among materials and removal of the
damaged concrete, steel preparation); application of products
and systems; quality control. In relation to the 2 first phases,
part 10 of NP EN 1504, they present orienting lines (through
Charts), of the procedures to be adopted according to the
chosen repair method. Regarding the quality control, the
standard presents the part 8 related to quality control and
evaluation of conformity of the products and systems and part
10 related to the application and quality control of the works.
On part 08 are Presentation of the European standard EN
of performance to guarantee that products and systems
respect the specifications contained on the other parts of the
Standard, as well as the indications related to equipment,
label of materials and monitoring. In part 10, (through
Charts) according to the method chosen, the tests and
observations to analyze the substrate condition, the confor-
mity of the products and systems to be applied and the
compliance of the requirements of quality are specified.
3.4 Case studies
3.4.1 Presentation of case studies; management strategies;
repair work project [11]
Because of the high competition on the practice of cases of
deterioration of the concrete caused by corrosion, four (4)
study scenarios will be presented on pages 12–14, being the
following:
1st case Corrosion caused by Carbonation actionLocated deployment of the concrete (Element punctually damaged)
2nd case Corrosion caused by ingression of Chlorides(Element punctually damaged)
3rd case Corrosion caused by Carbonation actionConcrete deterioration with partial (Element whose section is partially deteriorated)loss of the element section
4th case Corrosion caused by ingression of Chlorides(Element whose section is partially deteriorated)
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Admitting that the hypothetical works on cases 2 and 4
are in a marine environment (propitious to the penetration
of chlorides on the concrete interior by diffusion in aque-
ous solution) and on the cases 1 and 3, they are in prox-
imities of roads with high traffic (propitious to high
accumulation of carbon dioxide on the atmosphere, a
process of evaluation was initiated (part 9 of the Standard),
through a visual investigation at the works and was elab-
orated a local mapping of the visibly affected areas. From
the visual inspection resulted the following conclusions:
rust spots on the concrete surface in both cases, located
detachment of the covering layer on cases 1 and 2 and in an
advanced stage, partial loss of the of the element section
with exposed reinforcement, on cases 3 and 4. The pre-
sented symptoms endow with the predominant pathological
agents on the environment of local exposition of the
structures. Upon the realization of the preliminary inspec-
tion diagnostics auxiliaries are used such as crack monitor,
Table 1 Principles and Methods related to the degradation of the concrete matrix—NP EN 1504-9
Principles Methods
P1 [PI]—Protection against aggressive agents entrance MR1.1—hydrophobic impregnation
MR1.2—impregnation
MR1.3—surface coating
MR1.4—cracks locally sealed
MR1.5—crack filling
MR1.6—transformation of cracks into joints
MR1.7—external panels placement
MR1.8—application of membranes
P2 [MC]—humidity control MR2.1—hydrophobic impregnation
MR2.2—surface coating
MR2.3—physical protection or coating layer
MR2.4—electrochemical treatment
P3 [CR]—concrete restoration MR3.1—manual application of the mortar
MR3.2—new concreting
MR3.3—Mortar or concrete projection
MR3.4—elements substitution
P4 [SS]—structural reinforcement MR4.1—addition or substitution of external or internal reinforcements
MR4.2—reinforcement placement in existing or to do roles
MR4.3—reinforcement plates collage
MR4.4—mortar placement by hand
MR4.5—injection in cracks or gaps
MR4.6—filling of cracks or gaps
MR4.7—pre or post stressing
p5 [pr]—physical resistance MR5.1—covering or coating layers
MR5.2—impregnation
MR5.3—addition of mortar or concrete
P6 [RC]—chemical attack resistance MR6.1—covering or coating layers
MR6.2—addition of mortar or concrete
Principle 1 [PI]—reduction or prevention of the ingression of aggressive agents, such as water and other liquids, vapor, gases, chemical agents
(salts, acids) or biological, by blocking cracks or the concrete porosity
Principle 2 [MC]—humidity level control in the concrete on specified values intervals that reduces the occurrence probability of some pathology,
for example: alkalis-silica reactions and the cycles of frosting and de-icing
Principle 3 [CR]—original concrete restoration to the specified form and function, the concrete substitution must be done in case the type of
deterioration identified is the delamination, reinforcement corrosion, chemical attack, etc
Principle 4 [SS]—increasing or reposition of the structural capacity of an element of the structure, in cases this is found limited in its structural
function
Principle 5 [PR]—increase of the resistance to physical or mechanical attacks, being an example the superficial wear
Principle 6 [RC]—increase of chemical resistance of the concrete surface to the deterioration caused by chemical attack
J Build Rehabil (2017) 2:3 Page 7 of 12 3
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sclerometer, humidity sensor, etc, aiming to obtain the data
that can be correlated to the existing conclusions. However,
to reinforce the diagnosis it is needed to proceed to
determined tests that adequate to the case pathology.
Nowadays there is a great variety of tests that, beyond
beneficiating new technologies, are especially non
destructive tests, being classified in general as Structural
Tests (In-situ and Laboratory) and Durability Tests (In-situ
and Laboratory).
For the case of studies and in accordance with the
symptomatology presented on the work, we would opt for
the following tests:
• Determination in-situ of the chloride content: (2nd case
and 4th case).
• Determination of the deepness of the carbonation of the
concrete: (1st case and 3rd case).
• Thickness measure of the covering; (1st, 2nd, 3rd and
4th cases).
• Evaluation of the reinforcement corrosion rate through
the resistance polarization technique: (1st, 2nd, 3rd and
4th cases).
• Evaluation of the active corrosion risk of the reinforce-
ments by measurement of the concrete resistivity: (1st,
2nd, 3rd and 4th cases).
Based on the results obtained, (that is, in front of the
presence of chlorides and the deepness of the significant
carbonation to justify the reinforcement corrosion, much
more expressive for the higher destruction in cases 3 and 4,
in depth, of the passive layer and the consequent detach-
ment of the covering layers provoked by internal tensions
of the corrosion’s byproduct), it will be possible consecu-
tively to start the Repair Strategy. This comprehends in
each case on the most adequate choice of the Principles,
Methods, Products and Systems.
The principles and methods are in the standard’s part 9.
Once the causes are detected and the effects are confirmed
it is possible to establish the principles and the methods
regarding the rehabilitation of the structures. For the cases
of studies (in the presence of chlorides’ ions or carbona-
tion) the principles and methods are identical, existing
posteriorly systems and products more adequate to one
situation and another. Thereby, we can have the following
Principles associated to the strategy of rehabilitation,
according to the standard:
• Control of anodic areas (reinforcement corrosion);
• Preservation and restoration of the passivity (reinforce-
ment corrosion);
• Structural reinforcement (concrete deterioration);
Table 2 Principles and methods related to reinforcement corrosion—NP EN 1504 - 9
Principles Methods
P7 [RP]—preservation or restitution of the coat
passive layer
MR7.1—increase coating with mortar or concrete
MR7.2—substitution of the contaminated or carbonated concrete
MR7.3—electrochemical re-caustisizing of the carbonated concrete
MR7.4—re-caustisizing of the concrete through diffusion
MR7.5—electrochemical extraction of the chlorides from concrete
P8 [IR]—increase of concrete resistance MR8.1—hydrophobic impregnation
MR8.2—superficial covering
P9 [CC]—cathode control MR9.1—oxygen level limitation in the cathode by saturation of the concrete or
superficial coverings
P10 [CP]—cathode protection MR10.1—electric potential application
P11 [CA]—anodic areas control MR11.1—painting of the reinforcements with paints that contain active pigments
MR11.2—painting of the reinforcements with paints that work as barriers
MR11.3—application of corrosion inhibitors on the concrete
Principle 7 [RP]—preservation or restitution of the passive layer of the reinforcements, that shall be applied in cases where the reinforcements
are despassivated or in process of despassivation, thus limiting corrosion
Principle 8 [IR]—increase of the concrete electrical resistance. Intends to reduce the risk of corrosion evolution, limiting the changes between
anode and cathode, for example: through the diminishing of the humidity level of the concrete
Principle 9 [CC]—cathode control, aiming to avoid the formation of a cathode zone, for the electrochemical process not to happen which
originates the corrosion on the anodic zones
Principle 10 [CP]—cathode protection, implies on the creation of a system that avoids the formation of anodic zones
Principle 11 [CA]—anodic zones control, it is utilized to prevent the formation of anodic zones on the steel, appealing to its protection with
corrosion inhibitors
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• Restoration of the concrete (concrete deterioration);
• Protection against ingress (concrete deterioration);
• Increase of resistivity (reinforcement corrosion);
• Humidity control (concrete deterioration).
In front of the principles and methods assumed in each
case, follows the choice of the more efficient Products and
Systems, to the purposes they are intended to, considering
the technical and/or economical aspects. This task is sim-
plified as the suppliers of building materials have all their
products catalogued according to the NP EN 1504-9, being
disposed according to the principles and methods to which
they relate and to its objective. Table 3, adapted from [12],
shows an example of a Products and/or Systems Table of a
Portuguese manufacturer denominated R04, according the
Portuguese standard NP EN 1504-9.
Obviously all these products and systems, to be
approved by the Standard, go through a panoply of tests
and trials aiming the accomplishment of the identification
and performance requisites contemplated in parts 2 and 7
of the Standard.
As for the four cases of studies, the strategy of
rehabilitation aims at empowering the elements with
the characteristics of the aesthetics point of view and
of mechanical resistance, equal or superior to the
original conditions. Thus, principles, methods, products
and systems were adopted and the suppliers chosen in
a completely random manner. The selection of sup-
pliers (R 01; R 02; R 03; R 04), was based only on the
existence of technical catalogs available on the Inter-
net, thus providing a better understanding of the use of
concrete repair products, according to NP EN 1504-9.
Since the repair products presented in this manuscript
have no commercial intention, it is important to keep
in mind that the correct procedure for choosing sup-
pliers, must be based on the price/quality ratio, of their
products.
Analysis of the (4) case studies, considered in this paper
(Figs. 3, 4, 5, 6).
1st Case Element subject to carbonation action, punctu-
ally damaged. (Supplier R 01).
Symptoms/diagnosis: there is localized corrosion caused
by carbonation, but big part of the element is not affected
yet, thus, the repair and protection will be in the view of
prevention against carbonation of the element.
Principles/methods (superficial treatments on concrete
and steel):
• Control of anodic areas (CA)—application of active
covering of the reinforcement (Inks);
• Preservation or restoration of passivity (RP)—substitu-
tion of the contaminated or carbonated concrete;
• Repair of the concrete (CR)—mortar applied manually;
• Protection against ingress (PI)—application of covering
by painting;
• Resistivity increase (RI)—application of covering by
painting.
3rd Case Element subject to carbonation action, whose
section is partially deteriorated (Supplier R 03).
Symptoms/diagnosis: there is generalized corrosion by
carbonation, but part of the element is not affected yet, thus
the repair and protection will be done exhaustively and
extensive in the view of prevention against carbonation.
Principles/methods (superficial treatments on concrete
and steel):
• Control of anodic areas (CA)—application of active
covering of the reinforcement (Inks);
• Preservation or restoration of passivity (RP)—substitu-
tion of the contaminated or carbonated concrete;
• Structural strengthening (SS)—mortar Addition;
• Concrete repair (CR)—application of new mortar
(application of frames to hold the concrete);
• Protection against ingress (PI)—application of covering
by painting;
• Resistivity increase (RI)—application of covering by
painting.
Table 3 Principle and Method related to the reinforcement corrosion. (Adapted from [12])
Principle Description Method Solutions
:
Principle
10
Cathodic protection 10.1 Application of electric
potential
Covering mortar
Principle
11
Anodic zone control
Creating conditions to zones potentially anodic of the
reinforcement not to intervene on the reaction of the
corrosion.
11.1 Active covering of the
reinforcements
11.2 Protection covering of the
reinforcements
11.3 Application of inhibitors of
corrosion on or over the
concrete
Armatec-110 Epocem�,
MonoTop�-910 S
dur�-32 N
Inhibitors of corrosion of superficial
application and adjuvant
FerroGard�
J Build Rehabil (2017) 2:3 Page 9 of 12 3
123
2nd Case Element subject to the action of chloride ions,
punctually deteriorated. (Supplier R 02).
Symptoms/diagnosis: there is localized corrosion caused
by the action of chlorides, but great part of the element is
not affected yet, so the repair and protection will be in the
view of prevention against re-ingression of the chloride
ions.
Principles/methods (superficial treatments on the con-
crete and steel).
• Control of anodic areas (CA)—application of active
covering of the reinforcement (Inks);
• Preservation or restoration of passivity (RP)—substitu-
tion of the contaminated concrete;
• Repair of the concrete (CR)—mortar applied manually;
• Anodic areas control (CA)—application of inhibitors of
corrosion on the concrete;
• Protection against ingress (PI)—application of
hydrophobic impregnation;
Fig. 3 Articulation among market products and the principles and methods adopted—1st Case
Fig. 4 Articulation among market products and the principles and methods adopted—3rd Case
3 Page 10 of 12 J Build Rehabil (2017) 2:3
123
Fig. 5 Articulation among market products and the principles and methods adopted—2nd Case
Fig. 6 Articulation among market products and the principles and methods—4th Case
J Build Rehabil (2017) 2:3 Page 11 of 12 3
123
• Moisture control (MC)—application of hydrophobic
impregnation;
• Resistivity increase (RI)—application of hydrophobic
impregnation.
4th Case Element subject to the chloride ions, whose
section is partially deteriorated. (Supplier R04).
Symptoms/diagnosis: there is generalized corrosion by
the action of chlorides, but part of the element is not
affected yet, thus the repair and protection will be done
exhaustively and extensive in the view of prevention
against the ingress of the chloride ions.
Principles/methods (superficial treatment on the con-
crete and steel).
• Control of anodic areas (CA)—application of active
covering of the reinforcement (Inks);
• Preservation or restoration of passivity (RP)—substitu-
tion of the contaminated concrete;
• Structural strengthening (SS)—mortar addition;
• Concrete repair (CR)—application of new mortar
(application of frames to hold the concrete);
• Anodic areas control (CA)—application of inhibitors of
corrosion on the concrete;
• Moisture control (MC)—through the application of
coating by painting;
• Resistivity increase (RI)—through the application of
coating by painting.
There were much to say about a series of topics that
were not conveniently focused on the cases of studies,
being for example: the way of performing the preliminary
tests and utilized materials to confirm the diagnostic; the
nature, technical characteristics and the tests to which the
repair used products and systems must obey to guarantee
the performance requisites contained in parts 2–7 of the
Standard; the sequence on the application of the products
and systems, including the substrate preparation manner
(concrete and reinforcements); the quality control in the
course of developing of the works, including the tests
inherent to this control, described in part 10 of the Stan-
dard, as well as the technical compilation to provide to the
Owner of the Construction, whether it is about the devel-
opment of the work or about the future maintenance to give
to the repaired elements, etc. Truth is, that the thematic is
so extensive, that the proposal was to be restricted to the
most important aspects, aiming to permit the interested
evolution with enthusiasm as it is a world yet in develop-
ment, but that already presents very concrete results that
show it is in the right track. The simple fact that this
Standard compromises all the participating affects to the
rehabilitation of works, by itself, represents a historical
milestone without precedents. Finally, it should be noted
that the Standard embraces such an extensive and detailed
body of information (with special emphasis on the quality
control of the works, via organizational tables and charts),
that will permit even to the novice a gradual progression of
the knowledge, without undue difficulties.
This paper is a review paper, mainly intended for
beginners in repair of concrete structures, given the high
potential that it represents. The excellent organization and
depth of knowledge contained in the European Standard, is
more than a reason for its use, in current case studies.
The contribution of this standard to the scientific com-
munity has no limits, it will be useful both for beginners as
well as professionals seeking continuous improvement.
There are innumerable entities involved, which provide day
by day added knowledge. It stands out the scientific com-
munity (universities), which contributes significantly
through successive studies of research and the manufac-
turing companies of repair products, which contribute
through the successive launch of new products, thus pro-
viding improvement of the construction and repair pro-
cesses, each day more reliable, durable and sustainable.
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