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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 2
Guidelines for the development of concrete performance-based specifications in Brazil
and possesses the same properties. For that reason, a correla-
tion between the mixture pre-qualification and the quality control
requirements is needed.
In most cases, a single requirement is not sufficient to characterize
the behavior of concrete dominated by complex physical and chemi-
cal mechanisms which may be subjected to synergistic effects, where
several mechanisms are present (Baroghel-Bouny [13]). These re-
quirements must be measurable through reliable test methods, with
good repeatability. In addition, quality control test costs should be
taken into consideration and long-term tests are not recommended.
This paper focuses on requirements and specific performance cri-
teria based on analysis of specifications of other countries, math-
ematical modeling and experimental work performed by Tanesi [2].
The quality control requirements exceed the goals of this work and
will not be object of discussion.
3.2.2.1 Requirements related to constructability
and structural safety
The constructability requirements (fresh properties) depend on the
classes in NBR 6118/2003 (ABNT [6]) and the classes in EN
206/2000 (EUROCODE [7]) is suggested (Table 2).
3.2.2 Selection of performance requirements for
performance-based specifications
Several aspects should be considered when creating a performance-
based specification for concrete: structural safety requirements (me-
chanical properties), constructability requirements (fresh properties),
durability requirements (physical properties and durability) and sus-
tainability requirements (particularly environmental and lifecycle cost).
These requirements should be represented by a set of measurable
properties. Moreover, the intended service life must be defined.
The performance requirements can be specified for two distinct
phases: those related to properties that must be observed during
the mixtures design (pre qualification of mixtures) and those that
will be checked on the quality control during construction. Howev-
er, the quality control requirements should only be a tool to ensure
that the concrete received in the job site is the same mixture that
was chosen during the mixture design or pre qualification stage
Table 2 – Proposed exposure classes
Exposure Class
Type of exposure
Subclasses 1
I
Insignificant risk
of corrosion
2
1. Rural
2
2. Submerged
3. Indoors with low relative humidity
CB
Corrosion induced
by carbonation
1. Dry (indoor areas with low
humidity) or permanently submerged
2. Wet, rarely dry (surface in constant
contact with water, foundations)
3. Moderately humid (indoor areas
with high relative humidity and
outdoor areas sheltered from rain)
4. Wetting and drying cycles
CAM
Corrosion induced
by chlorides
1. Exposed to airborne salts but not
in direct contact with sea water
3
(coastal structures)
3
2. Permanently submerged (marine structures)
4
3. Tidal, splash and spray zones (marine structures)
5
AQ
Chemical attack
1. Slightly aggressive
3
2. Moderately aggressive
4
3. Highly aggressive
AND
Special exposure not
covered in other classes
1. Alkali-silica
2. Alkali carbonate
3. Concrete mass
4. Other
1
Specific limits should be defined for each sub class.
2
Exposure class I of NBR 6118/2003.
3
Exposure class III of NBR 6118/2003.
4
Exposure class IV of NBR 6118/2003.
5
42-
2+
4+
Specific limits for SO , Mg , NH , CO , pH should be specified for each sub class.
2