Fabric formed concrete involves using geotextile fabrics as formwork for concrete members. There are different techniques for construction depending on the type of falsework and how the fabric is configured. Woven polypropylene fabric is commonly used due to its strength and flexibility. Self-compacting concrete is typically used which can flow and compact itself without external compaction. Construction involves anchoring the fabric, placing the concrete, and then removing or leaving the fabric. Fabric formed concrete allows complex shapes and is used for beams, shells, walls and other structures.

1. FABRIC FORMED CONCRETE
Cyprus International University
Department of Civil Engineering
Ibrahim Inuwa Adamu
8TH December, 2015

2. TABLE OF CONTENT
• Title Page
• Table of Content
• Introduction
• Materials
• Mix Design and cost
• Techniques of Construction
• Applications
• Advantages
• Disadvantages
• Conclusion
• References

3. INTRODUCTION
Fabric formed concrete is a concrete which involves the use of geotextile fabrics as formwork for
concrete members. After the concrete hardens the fabric is either removed or left as an aesthetic.
Concrete which is a composite material composed of aggregates and a binder can be traced to a
few thousand years back. It was noticed from some Greek structures which still stand erect today
that some floors, arches, domes, vaults etc. were made of lime(binder) and pebbles(aggregate).
Modern day concrete came into existence after the discovery of Portland cement by Joseph
Aspdin in 1824. Concrete has evolved in terms of mix consistency, constituents, homogeneity and
applications over the centuries . Fabric formed concrete dates back to the roman times as history
has mentioned of a roman architect and engineer called Vitruvius explaining a method of
constructing two retaining walls by filling woven reed baskets with clay.

4. INTRODUCTION CONT’D
Reed is flexible and strong and was abundant at the time. This allowed the romans to build vaults,
cofferdams and underground chambers with it. Late within the second millennium some crucial
developments in fabric formed concrete took place and most of it is attributed to Gustav
Lilienthal. He was a German architect, builder, entrepreneur and inventor who had interest in
textile which led to him constructing a fabric formed suspended slab in 1899. The developments
made in the past 2 to 3 decades can be attributed to Prof. Mark West who is a builder and a
leading researcher of fabric formed concrete, Miguel Fisac, Kenzo Unno, Sandy Lawton and
Richard Fearn. These developments in fabric formed concrete has now allowed individuals to
freely express themselves through concrete with complex shapes, curves and forms.

5. MATERIALS
In the construction of fabric formed concrete the following materials are used
Geotextile fabrics
Self compacting concrete
Reinforcement
Concrete Canvas
GEOTEXTILE FABRICS are flexible fabrics of high strength which do not tare easily under loading.
They are sometimes referred to as polymer fabrics. They are made using polyolefin compounds
made from non-aromatic carbon and oxygen molecules. The woven geotextile fabrics are mostly
used.
There are two types that are used for fabric formed concrete

6. Woven Polyethylene fabrics
Woven Polypropylene fabrics
Woven Polypropylene is the most widely used in fabric formed concrete construction
POLYETHYLENE FABRICS
This was introduced in 1930
Properties :
 It is flexible
 They are resistant to Strong acids or strong bases and to gentle oxidants and reducing agents do
not harm it
 Relatively lower melting point(Depending on its density)

7.  Relatively weaker in strength(compared to polypropylene fabrics)
 Non bio-degradable
POLYPROPYLENE FABRIC
This was introduced in 1950
Properties:
• It has a higher melting point(compared to polyethylene fabric)
• Relatively stronger and doesn’t tare easily
• It is relatively Lighter and degradable
• Relatively lower resistance to chemical deterioration
• It is Flexible

8. Fig. 1. Polypropylene Fabric
Fig. 3. Polypropylene Fabric
Fig. 2. Polyethylene
Fabric
The figures below show examples of these fabrics

9. SELF COMPACTING CONCRETE is concrete which has a low yield stress, high deformability, and
moderate viscosity allowing it to flow easily and compact itself as it is placed without the use of
external compactor.
It consists of:
Aggregates
o Coarse aggregates: the shape and gradation are of concern here as they affect the mix
design. There should be a considerable amount of round shaped aggregates.
o Fine aggregate: the proportion is of concern(quantity)
Cement: Portland Cement is used in most cases but gypsum and other types of cement may also
be used depending on the outcome required.
Water
Mineral admixture such as fly ash are sometimes used to replace some quantity of cement

10. Viscosity Modifying Agent (in small quantity)
This is added so that fines content of a mix may be reduced without affecting the quality of the
concrete
Effects:
o Controls bleeding and segregation
o Enables flexibility in mix proportion
o Improves stability
High Range Water Reducers
Types
Steric hindrance: when this is used, a lower dosage is required.
o Acrylic copolymers
o Polycarboxylate

11. Electrostatic Repulsion
o Sulphunnated condensates of malamine
o Naphthalen Formaldehyde
Effects:
o It lowers the pumping pressure
o Increases workability
o Increases durability
REINFORCEMENT
Steel rebar
Steel wire mesh
Carbon Fibre mesh

12. Steel Fibre
Glass Fibre
CONCRETE CANVAS is a flexible, concrete impregnated fabric that hardens when hydrated to form
a thin, durable, water proof and fire resistant concrete structure(member).
The PVC backing is impermeable; water can not seep through it . It is prefabricated in a factory.

13. Fig. 4. Concrete Canvas
Fig. 5. Structure of concrete canvas

14. MIX DESIGN AND COST
MIX DESIGN
Normal concept of mix ratios are used except that the fines content is reduced if VMA is to be added
and increased if not. The proportions may be varied to suit the purpose for which the mix is to be
used. If mineral admixtures are to added they are considered when obtaining mix ratios.
Round aggregates are mostly used because they allow easier flow and thus minimum blockage
A low water cement ratio is used; water content of mix should be with in 160-200litres per cubic
meter of the concrete mix
Content of High Range Water Reducer is between 0.2% to 1.5%
Content of Viscosity Modifying Agent is Between 0.05% to 0.3%

15. Fig. 6. Difference of SCC mix and Normal
concrete mix
COST
Woven Polypropylene fabrics cost with in a range of $1,ooo to $2,500 per ton(1000kg) or about $1 per
square meter.
The construction of fabric formed concrete is relatively cheaper.

16. • The flowability of the fresh concrete can be tested with the V-funnel test, whereby the flow time is
measured. The funnel is filled with about 12 litres of concrete and the time taken for it to flow through the
apparatus is measured. T 5min is also measured with V-funnel, which indicates the tendency for segregation,
wherein the funnel can be refilled with concrete and left for 5 minutes to settle. If the concrete shows
segregation, the flow time will increase significantly. According to Khayat and Manai, a funnel test flow
time less than 6s is recommended for a concrete to qualify for an SCC.
• The passing ability is determined using the L- box test. The vertical section of the L-Box is filled with
concrete, and then the gate lifted to let the concrete flow into the horizontal section. The height of the
concrete at the end of the horizontal section is expressed as a proportion of that remaining in the vertical
section (H2/H1). This is an indication of passing ability. The specified requisite is the ratio between the
heights of the concrete at each end or blocking ratio to be ≥ 0.8.
• From Table 7; Mixes TR1 to TR9 were considered as trial mixes, as these mixes do not fulfil all the
requirements of the SCC mix. SCC1 to SCC5 are the SCC mixes that satisfy all the properties of SCC mixes
and determination of optimum water-powder ratio was carried out for these mixes.

19. Fig. 7. SCC Requirement for Concrete Members
Fig. 8. Effects of Constituents on SCC

20. Techniques of construction
The techniques of construction can be categorized by the type of falsework used and the configuration of
the fabric and the falsework.
There are two types of false work used
 Conventional falsework: the most widely used falsework in construction which is made of wood or steel.
Pneumatic falsework: is an inflatable balloon like falsework which is mostly used in the case of concrete
canvas or in the construction of domes and shells
There are different configurations of falsework and mostly each configuration is for a particular job. Some
of the configurations are:
The fabric is anchored at all edge and prestressed before the concrete is casted. The applied stress(pulling
or pushing) dictates the form of the casted member.

21.  The fabric is anchored freely at the edges allowing the weight of the concrete to dictate the form and
shape of the casted member.
 The fabric is anchored at four corners to create some buckling patterns; this is mostly done for shells.
 The fabric is draped over two edges or rails; mostly used for beams. It could also be draped over two
tables.
 The fabric is hung vertically from clips
 The fabric is anchored at edges and draped over interior falsework
 Two opposite edges of the fabric are joined clipped or stapled together to form a tube like formwork
The concrete can be applied in four different ways namely:
oBy hand- hands are used to rub and gently compact the concrete on an anchored fabric.
o Shotcrete- the use of shotcrete is mostly for fabric hung from clips to form thin shell after shotcreting.
o By pumping- the concrete is pumped using a concrete pump
o By pouring- this involves the use of pans, buckets or some kind of container to fetch and pour the
concrete into the fabric formwork.

22. Fig. 9. Column Formwork Fig. 10. Fabric Formed Beam
Fig. 11. Column Formwork

23. Fig. 12. Wall Panel Faleswork with Edge
Anchorage and Interior Falswork
Fig. 13. Hanging formwork for
Thin Shells

24. The influence of mechanical prestress is explained in terms of the two prestress directions which typically
correspond to the weave directions in woven fabrics. Figure 14 offers an indication as to what possibilities
are inherent in increasing one or both prestress values. Of course, these stresses act relative to the chosen
stiffness of the fabric and support conditions. The Gaussian curvature K is also shown for some categories,
where K is not equal 0 denotes double curvature, positive values = convex or concave shapes, and negative
values = saddle-like shapes. However, the type of fabric formwork does not necessarily dictate the expression
of curvature. If the applied prestress is low, the concrete loads will govern and force the formwork to bulge
outwards (forcing positive curvatures).

25. Fig. 14. Taxonomy of fabric formwork and formwork liners

26. APPLICATIONS
BEAMS
Rectangular and form-active structurally efficient beams can be constructed using fabric
formwork. The form-active structurally efficient beam consumes approximately 35% less
embodied energy than a comparable rectangular beam. The web of the beam is shaped to follow
the bending moment diagram for a specific type of load. The thickness of the flange of the beam
increases from the midpoint to the support and the web reduces in depth but widens to meet the
flange. Therefore the flange follows the shape of the corresponding shear force diagram. This
design configuration allows the beam to fail in flexure at mid-span by the primary steel yielding
and evades shear failure.

27. Fig. 11. Form-active Structurally
Efficient Beam
Fig. 12. Form-active Structurally
Efficient Beam

28. The concrete canvas is applied in
DOMES
REVETMENT BLANKET: to prevent river bank and shoreline erosion
FURNITURE: TABLES, COUCH ETC
DITCH LINING
How this is done can be seen in Fig. 17
Figures 15 and 16 show the step by step construction of a concrete canvas shelter
1. The concrete canvas is opened and unfolded
2. Then the attached inflatable balloon like falsework is inflated
3. The external surface of the concrete canvas is watered
4. Then it is left to dry and gain strength giving a rigid concrete structure

29. Fig. 16. Pneumatic falsework for concrete canvas
Fig. 15. construction of concrete
canvas shelter

30. Fig. 17.

31. Professor mark West and his research team have applied their knowledge of fabric formed concrete in
the construction of some structures. Two of theses structures are :
Hanil Engineering & Construction Co. Ltd corporate guest house and visitors centre in Seoul Korea
where wall panels of fabric formed concrete where needed.
Women’s Hospital in Winnipeg Canada where slabs 6x3.5m supported by columns were constructed.
And also branch columns were constructed.
Figures 20, 21, 22, 23, 24 and 25 show these fabric formed concrete members and their formworks.
 COLUMNS
 WALL PANELS
 TRUSSES
 SHELL STRUCTURES
 UNDERWATER PILES

32. Fig. 18. Hanil guest house
Fig. 20. Construction of Fabric Formed wall Panels for Hanil
guest house

33. Fig. 19. Women’s Hospital Winnipeg Canada
Fig. 25. Wall Panel combined with Branched Column

34. Fig. 21 Falsework for 6x3.5m slab supported by column
Fig. 22 fabric formwork for 6x3.5m slab
supported by
column

35. Fig. 23 6x3.5m slab supported by columns for the Women’s hospital
Fig. 24. Branched Column

36. ADVANTAGES
 Less concrete is used due to the ability of the fabric to form structurally efficient members
Less reinforcement is required due the same reason
Beautiful surface finish and architectural aesthetics
Improved concrete quality is achieved
Strength and impermeability is increased by filtering of air bubbles and excess water
Cost savings ; fabric costs less than conventional formwork
carbon dioxide emissions reduction due to the less concrete used to form structurally efficient
members; for the manufacture of cement accountable for some 5% of global CO2 emissions.

37. DISADVANTAGES
Complexity of shapes and forms makes structural analysis of members difficult
The use of finite element method is required for structural analysis and design
In some cases it may take longer time to construct due to the fact that the formwork has to be
designed and in some cases modelled.
The structural efficiency of some members have not yet been understood

38. CONCLUSION
Fabric formed concrete has pushed the boundaries of shape and form in regards to concrete
structures or elements further out.
Both precast and in-situ members can be constructed with fabric formed concrete.
Much research has been done on the architectural aspect of fabric formed concrete and more
research needs to be done on the structural aspect.

39. REFERENCE
Prof Mark West, 2009, “Fabric Formwork for Concrete Structures and Architecture”, International
Conference on Textile Composites and Inflatable Structures, Structural Membranes.
Lee S H, 2010, Study of Construction Methodology and Structural Behaviour of Fabric Formed
Concrete Beam, PhD Thesis, University of Edinburgh.
B. Persson, “A Comparison Between Mechanical Properties of Self-Compacting Concrete and the
Corresponding Properties of Normal Concrete,” Cement and Concrete Research, Vol. 31, 2001, pp.
193 – 198.
A.M. Manelius, 2009, “Ambiguous Chairs Cast in Fabric Formed Concrete”, International
Conference on Textile Composites and Inflatable Structures, Structural Membranes, Centre for
Industrialised Architecture (CINARK ), Institute of Technology at the Royal Danish Academy of Fine
Arts, School of Architecture, Copenhagen, Denmark.