Fibre Reinforced Concrete

Fibre reinforced concrete (FRC) is used in all areas of construction,
be it industrial, commercial, institutional or residential. Such technology goes back a long way: in the Roman empire, civil engineers
used animal and vegetable fibres in the construction of such wonders
as the Roman Colosseum, a structure that is now nearly two thousand
years old.
TYPES OF
FIBRES AND THEIR
PROPERTIES
AUGMENTE
LA RÉSISTANCE
RÉSIDUELLE
AMÉLIORE
LA DUCTILITÉ
ET LA TÉNACITÉ
(RÉSISTANCE POST-FISSURATION)
MEILLEURE
RÉPARTITION
DES CONTRAINTES
MÉCANIQUES
FIBRE REINFORCED CONCRETE
1
RENFORCER
LA STRUCTURE
DU BÉTON
TYPES OF FIBRES
AND THEIR PROPERTIES
SEVERAL TYPES OF FIBRES CAN BE
INCORPORATED INTO CONCRETE. BÉTON PROVINCIAL
OFFERS THE FOLLOWING:
Prevention
SYNTHETIC MICROFIBRES
Microfibres are primarily added to concrete to reduce plastic shrinkage, which can occur
at an early stage, when plastic concrete’s internal stresses are greater than its tensile
strength, that is, before the concrete adequately hardens. Specified standard quantities
are 0.6 to 1.8 kg/m3.
Retention
SYNTHETIC MACROFIBRES
Macrofibres added to concrete increase its residual strength, reinforce the concrete structure, and allow mechanical stresses to be more evenly distributed in the matrix. They also
improve ductility and fracture toughness (post-crack resistance), impact resistance and
fatigue strength.
Synthetic macrofibres can replace metal mesh and, in some cases, reinforcement beams,
in on-ground slabs, metal bridging and insulating formwork. Reinforcement beams have an
insubstantial effect on the number and spacing of cracks, only acting mechanically once
cracks are created. Steel reinforcements and mesh are reactive rather than preventative,
having no effect until a crack appears.
Through research and development, we have applied a technology of structural reinforce-
FIBRE REINFORCED CONCRETE
2
ment to the following:
- On-ground slabs
- Shotcrete
- Composite slabs
- Precast concrete (septic tanks, barriers, etc.)
The specified standard quantities are 2 to 9 kg/m3. Depending on the fibre type, quantities
can vary between 1.8 and 11 kg/m3. Unlike microfibres, macrofibres, due to their low
specific surface, can be used in large quantities.
Retention
METAL FIBRES
Metal fibres offer the ideal tensile strength to tear strength ratio. The performance of metal
fibres depends largely on two factors:
1) Their distribution (kg/m3)
2)Their specifications
(Length and diameter, Tensile strength,
Type of anchor)
The many uses of metal fibres primarily include on-ground slabs, warehouse floors that support heavy loads or
endure large impacts, aerated concrete roofing components, roadway paving, bridge decks, refractory materials
(stainless steel), the design of precast elements, heat-resistant and explosion-resistant structures, and tunnel
pavement.
Specified standard quantities are 15 to 45 kg/m3. Depending on the fibre type, quantities can vary between
15 and 150 kg/m3 for normal concretes requiring slight adjustments in their formulation.
SLUMP CONTROL AND THE ADDITION OF SUPERPLASTICIZER
For all fibre types, the addition of superplasticizer is strongly recommended in order to avoid adding excess
water to the mix at the work site, and to render the concrete more fluid before fibres are inserted.
Slump control is also very important: the slump for a basic mix of non-fibre reinforced concrete is normally
specified at 80 +/- 20 mm. For fibre reinforced concretes, it is often necessary to adjust the slump before adding
fibres, in order to make the concretes more fluid. Even when fibres are added to a premix, certain fibres require
that the slump/fluidity be increased in order obtain a more even mix.
For example, if the steel fibre concentration is to be between 20 and 40 kg/m3, an initial slump of between
FIBRE REINFORCED CONCRETE
3
130 and 190 mm should be aimed for.
› Canac Marquis Grenier
TECHNICAL ADVANTAGES TO
FIBRE USE
THE THREE-DIMENSIONAL REINFORCEMENT
THAT IS UNIFORMLY DISTRIBUTED ACROSS
THE CONCRETE MATRIX IMPROVES CONCRETE’S:
direct tensile
strength
bending
strength
impact
resistance
BY UP TO
BY UP TO
BY UP TO
40 % *
150 %*
abrasion
resistance
a reduction
of shrinkage
cracks
BY UP TO
45 %
40 %
fatigue
strength
blast
resistance
BY UP TO
93 %
› A reduction of aggregate settling, which reduces the risk of capillaries forming and thus
prevents excessive bleeding;
› An increase in the resistance to cracking, and a significant reduction in the length
of cracks when they do appear;
› No corrosion, in the case of synthetic fibres.
* (Association béton Québec and Cement Association of Canada, 7th edition, 2004, p. 122)
FIBRE REINFORCED CONCRETE
4
Sources
› Galeries de la Capitale
› Metro Plus GP
› Galeries de Beauport
ECONOMIC ADVANTAGES TO
FIBRE USE
Fibre use reduces the number of work site employees needed
to install metal meshes or other reinforcements. This equals
a SUBSTANTIAL REDUCTION in the time required for
construction.
FIBRE REINFORCED CONCRETE
5
For example, if one considers that two to three workers can
install, on average, 10,000 ft2 of mesh daily, this would
mean that with the use of fibre concrete, ten days fewer
would be required for the installation of a 100,000 ft2 floor.
FINISHING
FIBRE CONCRETE
Fibre concrete can be finished using traditional techniques, but certain precautions should be
taken to prevent fibres from showing on the surface and to minimize the risk of damage to saw
kerfs when sawn control joints are being placed. Such precautions include:
› using a double trowel;
› placing the trowel as flat as possible against the surface of the concrete;
› bull floating after screeding;
› using screeds and laser equipment.
It is important to:
› avoid the use, as much as possible, of a single trowel finishing machine and a trowel
at pronounced angles;
› have performed an adequate levelling before finishing;
FIBRE REINFORCED CONCRETE
6
› not begin finishing at a premature or late stage, nor to do the finishing by hand.
Thirty kilograms of steel
fibres per cubic metre
of concrete
2
The placement
of concrete
3
Finished
concrete
7
The pouring of
fibre concrete
FIBRE REINFORCED CONCRETE
1
› SAQ Dépôt
BÉTON PROVINCIAL
PROVINCIAL
BÉTON
EST
UNE ENTREPRISE
IS
A STRONGLY
SOLIDEMENT IMPLANTÉE
ESTABLISHED
EASTERN
DEPUIS PRÈS
D’UN DEMICANADIAN
COMPANY
SIÈCLE
DANSTO
L’EST
WITH
CLOSE
50
DU CANADA.
YEARS'
EXPERIENCE.
Le groupe
Béton
Provincial
ltée est
groupe
intégré
dans
le customers.
secteur de la
The
company
forges
strong, lasting
tiesun
built
on respect
withœuvrant
its partners
and
construction.
en 1960,
l’entreprise
est
constamment
l’affût
de meilleures
Béton
ProvincialFondée
is a partner
you can
trust for all
your
projects, fromà the
simplest
to the
solutions
pour ses clients situés au Québec et dans les Maritimes.
most
complex.
NUMBER
PLANTS BY
NOMBREOF
D’USINES
PARCATEGORY
CATÉGORIES
QUARRIES
CARRIÈRES
PRECAST
CONCRETE
BÉTON
PRODUCTS
PLANTS
PRÉFABRIQUÉ
55
PAVING PLANTS
BÉTON BITUMINEUX
15
15
8
Une flotte de
BÉTON RENFORCÉ DE FIBRES
25
25
350
concrete mixers
bétonnières
75
75
ready-mixed
usines
concrete plants
de béton préparé
L'Étape
Saguenay
Québec
(Administrative office)
Trois-Rivières
La Tuque
Alma
Roberval
Saint-Félicien
Dolbeau
Saint-Jérôme
Clermont
Lévis
Baie-Saint-Paul
QUÉBEC
Drummondville
Sorel
Notre-DameBoucherville
du-Bon-Conseil
Saint-Hyacinthe
Montréal-Est
Granby
Ville Saint-Laurent
Ville des
Laurentides
Chibougamau
Chapais
Piedmont
Eastmain 1A
Béton Provincial plant location
Ready-mixed concrete plant
Paving plant
Concrete products plant
Aggregate
LEGEND
Dalhousie
Saint John
La Romaine
Chandler
Havre-Saint-Pierre
New Carlisle
New Richmond
Murdochville
Gaspé
NOUVEAUBRUNSWICK
Nackawic
Woodstock
Florenceville
Nouvelle
Campbellton
Amqui
Saint-Quentin
Perth-Andover
Grand Falls
Edmundston
St-François
Rivière-du-Loup
Sept-Îles
Sainte-Anne-des-Monts
Port-Cartier
Matane (Head office)
Mont-Joli
Rimouski
Trois-Pistoles
Les Escoumins
Forestville
Baie-Comeau
Route 389
Fermont
LABRADOR
Goose Bay
Wabush / Labrador City