ex performance special concrete range...usual concretes not being able to meet these needs, there...
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High performance concrete
EX3 Performance special concrete range
Technical data sheet
High performance concrete 3
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The development in Romania, over the past
years, of several large scale projects required multiple special demands for concrete. The usual concretes not being able to meet these
needs, there were developed concrete with specific/representative properties adapted to
these types of projects.
High performance concrete General information
Areas of use
Art works: arches, bridges, passages, viaducts,
tunnels, etc.;
High civil or industrial buildings or constructions
High performance concrete is a special concrete,
developed to fulfill certain combinations of performance
and uniformity criteria.
High performance concretes:
• meet some standards more complex in comparison to
those of usual concretes;
• fulfill both the technical and the economic
requirements.
If, in case of usual concretes, traditionally, the
compression resistance is the main required
feature, in case of high performance concretes may
prevail other properties such as the elasticity
module, the resistance to impact/ abrasion, low
permeability, etc..
• .
with special requirements and demands (for
example: curved thin slabs);
• Hydro technical works in aggressive
environments, nuclear constructions;
• Constructions with resistance needs in case
of chemical attack, (for example: agricultural
constructions), where this concrete may
have the purpose of inhibitor agent regarding
the evolution and propagation of bacteria
and the appearance of moulds.
Exposure range (according to CP 012-1:2007) Usually, the high performance concretes respond to all conditions derived from the combination of the exposure
classes, mostly due to their low permeability.
Corrosion due to
carbonation
Corrosion due to
chlorides having
other origin than
marine
Attack of frost -thaw in
saturated status with
water and thawing agents
Chemical attack Mechanical
stress by wear
XC1, XC2, XC3, XC4 XD1, XD2, XD3 XF1, XF2, XF3, XF4 XA1, XA2, XA3 XM1, XM2, XM3
Note: According to tables F1.1 F1.2 of Code of practice for the concrete production CP012-1: 2007, the requirements regarding driven air, the
type of aggregate, the cement type, the surface treating, etc. shall be complied with.
High performance concrete General information
High performance concrete is a special concrete,
developed to fulfill certain combinations of
performance and uniformity criteria.
High performance concretes:
• meet some standards more complex in
comparison to those of usual concretes;
• fulfill both the technical and the economic requirements.
If, in case of usual concretes, traditionally, the
compression resistance is the main required
feature, in case of high performance concretes
may prevail other properties such as the
elasticity module, the resistance to impact/
abrasion, low permeability, etc..
The criteria at the basis of the establishment
of the high performance concrete's
composition are:
• The use of a cement of constant, superior quality
(with high content of silicate tricalcium, low
content of aluminates tricalcium);
• The reduction of the water/ cement ratio below
0.35, using a water reducer strong additive (super
plasticizers of the latest generation);
• The use of some aggregates with high resistance
to crushing and a high elasticity module, paying
special attention to the sizes, the shape, the
texture, the absorption, etc.;
• The improvement of the mineral frame (matrix) by
the addition of ultrafine materials, such as micro-
silica in order to increase the concrete's
compaction
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Characteristics of high performance concrete
The high performance concrete, in fresh
condition, presents features similar to the usual
concrete. He is framed in the settling classes
S3-S5, having a higher viscosity due to the large
quantity of fine material present in the receipt.
In hardened condition, the high performance
concrete has special features, as it follows:
Resistance to compression
The high performance concrete is mainly characterized
by a high resistance to compression at 28 days and a
significant evolution of this after this age.
Comparatively with the usual concretes, the high
performance concretes present a very high initial
resistance. It must be given a special attention to the
sample taking and testing procedures (including to the
testing equipment), because, at very high resistances, the
standard allowed deflection is high, with negative impact
on the uniformity coefficient. An irregular surface or with
deflections from the flatness of the testing sample may
lead to completely wrong results. Following, there are
presented the evolutions in time of the compression
resistances of the high performance concrete produced
by Holcim Romania.
Term/Class
1 day
7 days
Resistance to compression*
28 days
56 days
90 days
C40/50 40,4 60,67 69,08 69,80 72,59
C50/60 55,07 69,85 75,48 77,23 80,51
C60/75 62,6 79,77 86,87 89,37 89,90
C70/85 73,42 97,07 110,48 112,59 112,94
C80/95 81,5 103,58 116,595 123,6 124,56
C90/105 85,3 107,92 125,29 126,76 127,34
Advantages of high performance concrete
Construction's safety
• High durability/ long life expectancy
• High resistance to compression and extension
• High elasticity module
*Tests performed in lab conditions
Resistance to compression
• High resistance to abrasion – + • Low permeability to water and gas
• Superior resistance to chemical attack
• High resistance to frost-thaw, including in the presence of thawing agents
• Resistance to impact
Flexibility
• Execution of all types of structural elements (pillars, beams, walls, slabs, etc.) – + • Execution of complex architectural works • Execution of thin section elements or of structures with wide openings
Protection of humans and of the environment
• Execution of sustainable constructions by increasing the life duration from 50 to 100
years
• Resistance to bad weather conditions and earthquake – +
• Resistance to explosions
• Inhibition of bacteria evolution and of mould appearance
Resistance to extension
As in the case of usual concretes, the resistance to extension rises together with the resistance to compression,
Class
Resistance to extension 28 days (MPa)
By shear* By bending
Cost reduction
• Reduction of the construction duration/ Rapid construction rhythm
due to initial very high resistances
• Reduction of the volume of concrete – + • Reduction of the cladding quantity
• Wider openings (significant advantage to bridges by reducing the costs with the piles and the afferent
foundations)
but the increase is slower. It must be mentioned that there
is no direct proportional relationship between these
characteristics. Factors such as the shape of the
aggregate, its absorption or the petrography nature may
influence more one of these resistances.
C40/50 4,12 7,2
C50/60 4,29 8,2
C60/75 4,52 8,76
C70/85 5,45 9,45
C80/95 5,84 10,1
C90/105 7,86 10,4
*applied according to EC2 by direct extension = 0,9*fct
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C80/95 112,1 43,1 40,9 All these characteristics of high performance concretes collaborate to insure a high durability, respectively a life
C90/105 114,3 42,6 41,1 duration of over 100 years, for the structural class S4.
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Elasticity module
The high performance concrete, in comparison
with the usual concrete, has a more obvious
monolith character, and the resistance of the
interface area matrix-aggregate is higher. The
interface's crazing is more reduced, and the linear
portion of the curve effort-deflection is expanded until
a demand which can be even over 85% of the
breaking requirement.
The breaking, usually takes place through the matrix
but also through the coarse aggregate.
Carbonation
The compact structure of high performance concretes
involves a better behavior for carbonation. From the studies
made in collaboration with Bucharest Technical University, it
resulted that the high performance concretes exposed in an
environment rich in 𝐶𝑂2 are practically waterproof to this
agent.
Class concrete
Resistance cube MPa
Elasticity
module experimentally
established
Reference values
EC2
Type of aggregate
Closed surface
The absence of open pores at the surface of high C40/50 67,8 39,5 39,1
Quartzous C50/60 71,4 39,9 39,7
C60/75 84,3 39,9 37,5
performance concrete inhibits the evolution of living
micro- organisms (bacteria, fungus), as well as the
appearance of moulds.
C70/85 101,0 42,6 39,6 Quartzous sandstones
Slow flow
In case of high performance concretes, this feature has
much lower values than for the usual concretes,
especially at the concretes containing superfine silica.
Comparatively with the normal concretes, from a
Contraction
In case of high performance concretes, their total
contraction is similar to that of regular concretes, but
having a different kinetics. The endogenous contraction
may be 2-3 times bigger (because of the very fine micro
structure), while the plastic contraction, of drying, is much
kinetic point of view, the flow settles more rapidly. The slow flow
is inversely proportional with the resistances increase.
smaller due to the low water/cement ratio. The high performance
concretes are very sensible to the rapid evaporation of water in the
first hours, therefore it is extremely important to appropriately
protect/treat the freshly poured/ dismantled surfaces.
*Control value calculated according to Eurocode 2 on the base of the experimental results obtained by compression testing
Permeability
Due to low porosity, t he high performance
concretes have a much reduced permeability. To
classes higher than C60/75, this tends towards
zero even at a pressure of 12 atmospheres.
Resistance to frost-thaw
Contact
Brașov:
121 Zizinului Street, RO500407
Tel: +40 740 110 506
Bucharest Chitila:
423 Chitilei, District 1
Tel: +40 740 110 430
Bucharest Clinceni:
Parcel 10, Tarlaua 43, Clinceni Commune, Ilfov
County; Tel: +40 740 110 430
Bucharest Pantelimon:
Bucharest Ring Road, no. 8, District 2;
Cluj-Napoca:
11 Beiușului Street, RO400394
Tel: +40 740 110 433
Craiova:
401 Râului Street, RO200636
Tel: +40 740 110 438
Oradea:
14/C Borșului Street, RO410605
Tel: +40 752 069 118
Ploiești:
48A Centura de Est Street, RO100187;
Sibiu:
12 Turda Street, RO550052
Tel: +40 754 054 710
Târgu Mureș:
8 Bãneasa Street, RO540199
Tel: +40 747 079 963, +40 757 010 985
Timișoara:
17 Moșniței Road, RO300547
Tel: +40 745 643 708
Due to its dense structure and its reduced water quantity in the system, the high performance concretes have a very good behavior at frost-thaw. Up to the resistance class C55/67, there may appear exfoliations caused by the presence of salt as thawing agent. From the studies
made by Lafarge-Holcim group, it shows that at higher classes, where the concrete contains micro-silica, there were no more exfoliations as following the application of the thawing agents (in 56 cycles of frost- thaw), even in case of not using a driven air additive.
Tel: +40 740 110 430
Bucharest Pipera:
52 Pipera Highway, District 1
Tel: +40 740 110 430
Tel: +40 740 110 553
Satu Mare:
146 Careiului Road, RO440187
Tel: +40 740 110 580
Terms/Class
14 days
Contraction to drying ( ‰)
21 days
28 days
Control value*
C40/50 0,0500 0,1109 0,2377 0,25
C50/60 0,0486 0,1007 0,2181 0,24
C60/75 0,0399 0,0978 0,1920 0,21
C70/85 0,0290 0,1058 0,1674 0,16
C80/95 0,0471 0,0848 0,1435 0,15
C90/105 0,0681 0,1043 0,1399 0,14
OBS: The reference values were calculated on the base of experimentally established resistances, with the formula Ecm=22[(fcm)/10]0,3
and the application of the correction depending on the type of aggregate.
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Holcim (Romania) S.A.
169 A Floreasca Street
Building B, 7th Floor
District 1, RO 014459
Bucharest, Romania
www.holcim.ro
© 2016 Copyright Holcim (România) S.A.