Fiber Reinforced Conrete - iam.tugraz.at · Reinforced concrete itself is a composite material, where the reinforcement acts as the strengthening fibre and the concrete as the matrix

Fiber Reinforced Conrete

Alice DemenyiHenrik Jonestrand

Eva Pratschke

140.804 New Materials and Methods of Building Supporting Structures


TIMELINE

The concept of using fibers as reinforcement is not new. Fibers have been used as reinforcement since ancient times. Historically organic fibers from horsehair was used in mortar and grass straws were mold into mud bricks to increase the strength.

In the early 1900s, asbestos fibers were used in concrete. A half century later the 1950s the concept of composite materials came into being. Fiber reinforced concrete was one of the topics of interest. There was a need to find a replacement for the asbestos used in concrete and other building materials once the health risks associated with the substance were discovered.

By the 1960s, steel, glass (GFRC), and synthetic fibers such as polypropylene fibers were used in concrete, and research into new fiber reinforced concretes continues today.

1900 1950 1960

Asbestos Fiber

Ancient

Organic FiberHorsehair / GrassIn morts and bricks

Glass FiberSteel FiberSynthetic Fiber

1990

Carbon FiberCompositesinvented

HISTORY

Mud bricks with organic fibers

APPLICATIONS• Facade Panels• Shotcrete / Underground Concrete (Tunnels for

example)• Precast Concrete• Commercial Slabs

BENEFITSIncreases the tensile strength of the concrete.

Reduces the air voids and water voids the inherent porosity of gel.

Increases the durability of the concrete.

Fibres such as graphite and glass have excellent resistance to creep, while the same is not true for most resins. Therefore, the orientation and volume of fibres have a significant influence on the creep performance of rebars/tendons.

Reinforced concrete itself is a composite material, where the reinforcement acts as the strengthening fibre and the concrete as the matrix. It is therefore imperative that the behavior under thermal stresses for the two materials be similar so that the differential deformations of concrete and the reinforcement are minimized.

It has been recognized that the addition of small, closely spaced and uniformly dispersed fibers to concrete would act as crack arrester and would substantially improve its static and dynamic properties.


• Uniformly Distributed Fibers• Possible to cast very thin elements

70-90% thinner compared to normal concrete• More fluid than normal concrete

COMPARISON OF SHORT FIBER TYPES


ACRYLIC

ASBESTOS

CARBON*

AR GLAS

POLYETHYLENE*

STEEL

DIAMETER

ACRY

LIC

ASBE

STO

S

CARB

ON

MIT

SUI

CARB

ON

PAN

CARB

ON

PITC

H

AR G

LASS

POLY

ETHY

LENE

POLY

VINY

LAL

COHO

L

FIBR

ILLA

TED

POLY

PRO

PYLE

NE

STEE

L


18 2010

0.5

18

60

90

200 600

µm


ACRY

LIC

ASBE

STO

S

CARB

ON

MIT

SUI

CARB

ON

PAN

CARB

ON

PITC

H

AR G

LASS

POLY

ETHY

LENE

POLY

VINY

LAL

COHO

L

FIBR

ILLA

TED

POLY

PRO

PYLE

NE

STEE

L

SPECIFIC GRAVITY

1.18

3.5

1.6 2 1.72.7

0.91.4

0.9

7.8

kg/m3

ACRY

LIC

ASBE

STO

S

CARB

ON

MIT

SUI

CARB

ON

PAN

CARB

ON

PITC

H

AR G

LASS

POLY

ETHY

LENE

POLY

VINY

LAL

COHO

L

FIBR

ILLA

TED

POLY

PRO

PYLE

NE

STEE

L

TENSILE STRENGTHFiber Reinforced Conrete

1

3.5

1

3.6

1.72.5

0.2 0.150.7

2.0

GPa

ACRY

LIC

ASBE

STO

S

CARB

ON

MIT

SUI

CARB

ON

PAN

CARB

ON

PITC

H

AR G

LASS

POLY

ETHY

LENE

POLY

VINY

LAL

COHO

L

FIBR

ILLA

TED

POLY

PRO

PYLE

NE

STEE

L

TENSILE MODULUS(STIFFNESS)


GPa20

190

75

400

32

70

2.512.5

10

200

ACRY

LIC

ASBE

STO

S

CARB

ON

MIT

SUI

CARB

ON

PAN

CARB

ON

PITC

H

AR G

LASS

POLY

ETHY

LENE

POLY

VINY

LAL

COHO

L

FIBR

ILLA

TED

POLY

PRO

PYLE

NE

STEE

L

STRAIN TO FAILURE

%


11

3 31.5 5 3.6

10 118

3.5

_a composite of high strength glass fiber [alkali resistant glass fibers]embedded in a polymer concrete matrix_the fibers are the principal load-carrying members, transfer loads from one fiber to another via shear stresses through the matrix

STRUCTURAL PROPERTIES OF GFRC

_shape flexibility > used for complex, three dimensional shells where loads are light_durability expected to last as long as pre-cast concrete [in environments, as when exposed to salt spray or high moisture, the GFRC can be expected to perform better, as there is no steel reinforcement to corrode]_made of minerals > not burning, acts likes a thermal regulator when exposed to flame [it also protects the materials behind it from the heat of the flame]_the orientation of the fiber determines how effective that fiber resists the load [the more ran-dom the orientation, the more fibers are needed to resist the load]_typical GFRC mix uses a high loading of glass fibers to provide sufficient material cross-sec-tional area to resist the anticipated tensile loads [a loading of 5% fiber by weight of cementitious material is used]

GLASS FIBER REINFORCED CONCRETE [GFRC]

random, three-dimensional (3D) reinforcing random, two-dimensional (2D) reinforcing one-dimensional (1D) reinforcing

LEVELS OF REINFORCEMENT


Laminates_ adhering and consolidating thin layers of fibers and matrix into the desired thickness_the fiber orientation in each layer as well as the stacking sequence of various layers can be controlled to generate a wide range of physical and mechanical properties for the composite laminate

APPLICATIONS

Sandwich panels_composite of three or more materials bonded together to form a structural panel_it takes advantage of the shear strength of a low density core material and the high com-pressive and tensile strengths of the GFRC facing to obtain high strength to weight ratios_sandwich panels and functions of the individual components may be described by making an analogy to an I-beam

Spray-up_spray-up is similar to shotcrete in that the fluid concrete mixture is sprayed into the forms _the concrete and fibers mix when they hit the form surface_typically Spray-up is applied in two layers

Premix_ involves mixing shorter fibers in lower doses into the fluid concrete_this mixture is either poured into molds or sprayed_tends to be less strong than spray-up due to the shorter fibers and more random fiber orienta-tion

CASTING METHODS


L Oceanica Valencia - Steel Fiber Reinforced Concrete 6cm thick shells


Negative Formwork

Structure under the Formwork

Year 1999 Valencia, SpainStatus CompletedClient Ciudad de las Artes y las Ciencias S.A.Floor Area 1,200 m2Budget 1.500.000 EurosMaterial Steel Fiber Reinforced Concrete (6cm)


Zaha Hadid - Zaragoza Bridge - Glass Fiber Reinforced Facade Panels


Zaha Hadid Roca London Gallery - Glass Fiber Reenforced Concrete

Renovation of 1984 National Soccer Stadium of South Africa

Glass Fiber Reinforced ConcreteFacade Panels

Colored with Lanxess Pigment

Populous ArchitectsBoogertman Urban Edge + Partners


National SoccerStadium South Africa 1988- Steel Fiber Reenforced Concrete


National SoccerStadium South Africa 1988- Steel Fiber Reenforced Concrete


Zaha Hadid Roca London Gallery - Steel Fiber Reenforced Concrete

PropertiesDecorative, luminous, strong

AppicationInterior architecture and signage

Technical SpecificationsDimension 500 x 1000mm up to 1000 x 1500mmDensity ca. 2300 kg/mColours white or grey

_translucent, multi-layered concrete_surfaces are polished to a shiny finish and impregnated with a water repellent_the fibers are arranged [woven]in the concrete so as to cre-ate a motif / pattern or a luminous message_a light source is place behind the devise to energise the component

CONCRETE WITH OPTICAL FIBERS


PropertiesTranslucent, fine thickness, decorative and flexible

AppicationAutomotive and yacht engineering, room furnishings and decor

Technical SpecificationsMax dimension 100 x 50cmThikness 0.8mm a film sublayer allows 3d shape creation

_composition: layers of concrete and optical fiber _high UV resistance _can be cutted, glued, perforated

CONCRETE AND QUARZ OPTICAL FIBER



1) Wilkins, Dick J. (ed.), JTEC Panel Report on Advanced Manufacturing Technology for Polymer Composite Structures in Japan, Japanese Technology Evaluation Center, Baltimore, MD, NTIS PB94-161403, April 1994. (http://itri.loyola.edu/polymers/).

BIBLIOGRAPHY

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Fiber Reinforced Conrete - iam.tugraz.at · Reinforced concrete itself is a composite material, where the reinforcement acts as the strengthening fibre and the concrete as the matrix