CHAPTER II
LITERATURE REVIEW
2.1
Definition of Ferrocement/Ferrogrout
As the material ‘ferrocement’ was used for a long time in boat building and
similar allied structures rather than in structural applications, a rigorous engineering
definition of ferrocement was not followed. Within ACI Committee 549, a
considerable discussion on its definition evolved and it was agreed to group together
various available definitions from many sources to come up with a concise and
accurate definition that may be acceptable to the engineering profession. Some
definitions considered by the committee are presented here.
Bigg (1968) has discussed the problem of definition in detail. He pointed out
that according to the American Bureau of Shipping it is:
“A thin, highly reinforced shell of concrete in which the steel
reinforcement is distributed widely throughout the concrete, so that
the material under stress acts approximately as a homogenous
material. The strength properties of the material are to be determined
by testing a significant number of samples....”
Although at first glance, the above definition seems an acceptable one, it
brought about a number of questions on the words italicised therein, which may have
different meanings of ferrocement to different people. Bigg went on to discuss
various aspects of ferrocement, suggests various ways of defining it, such as a
6
composite material and points out how the available engineering approach for
composites of fiber reinforced concrete may be used to come up with a definition of
ferrocement.
As a two-component composite, made up of reinforcement and mortar
(matrix), Bezukladov (1968) defined it in terms of the ratio of the surface area of
reinforcement to the volume of, the composite. In this manner, ferrocement is
separated from the conventional reinforced concrete. Somewhat arbitrarily, he
assigned the specific surface greater than 2cm2/cm3 to ferrocement which then
behaves more or less as a homogenous material. Less than 2cm2/cm3 is considered
reinforced concrete.
Shah (1974) in discussing different materials of construction, defined
ferrocement in a manner similar to Bezukladov. He called it a composite made with
mortar and a fine diameter continuous mesh as reinforcement, with which has higher
bond due to its smaller size and a larger surface area per unit volume of mortar.
Accordingly, this ratio may be as mush as ten times that which is observed in
conventional reinforced concrete; this results in failure of ferrocement in tension by
the actual breaking of wire mesh and a much higher cracking strength in the matrix.
As a composite, certain characteristics of ferrocement may thus be
summarised as follows:
a.
Since the wire mesh (reinforcement) is much stronger in tension compared to
the matrix (mortar), the role of the matrix is to properly hold the mesh in
place, to give a proper protection and to transfer stresses by means of
adequate bond.
b.
Compression strength of this composite is generally a function of the matrix
(mortar) compressive strength, while the tensile strength is a function of the
mesh content and its properties.
c.
It follows from (b) above that the stress-strain relationship of ferrocement in
tension may show either a complete elastic behaviour (up to fracture of
reinforcing mesh) or some inelasticity depending upon the yielding properties
of the mesh.
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d.
Since the properties of this composite are very much a function of orientation
of the reinforcement, the material is generally anisotropic and may be treated
as such in the theoretical analysis.
The above discussion indicates the variety of approaches that have been made
in a structural definition of ferrocement. It became apparent to the ACI Committee
549 that the first task should be to define Ferrocement as a construction material.
Accordingly, the following definition was adopted:
"Ferrocement is a type of thin wall reinforced concrete commonly
constructed of hydraulic cement mortar reinforced closely spaced
layers of continuous and relatively small wire diameter mesh. Mesh
may be made of metallic or other suitable materials."
The above definition implies that although ferrocement is a form of
reinforced concrete, it is also a composite material. Hence the basic concepts
underlying the behaviour and mechanics of composites materials should be
applicable to ferrocement.
2.2
History of Ferrocement/Ferrogrout
The use of ferrocement was first started as early as in 1848. It took the form
of a rowing boat constructed by Jean Louis Lambot. The boat, still in a remarkably
good condition, is on display in a museum at Brigholes, France. Since then,
ferrocement was mainly used in the marine environment.
In the early 1940s, Pier Luigi Nervi resurrected the original ferrocement
concept when he observed that reinforcing concrete with layers of wire mesh
produced a material possessing the mechanical characteristics of an approximately
homogeneous material and capable of resisting impact. After the Second World
War, Nervi demonstrated the utility of ferrocement as a boat-building material. His
firm built the 165-ton motor sailor Irene with a ferrocement hull about 36mm thick.
8
Ferrocement gained wide acceptance only in the early 1960s in United
Kingdom, New Zealand, and Australia. In 1965, an American-owned ferrocement
yacht built in New Zealand, the 16m Awahnee, circumnavigated the world twice
without serious problems, although it encountered several mishaps.
Nervi built a small storehouse of ferrocement in 1947 which was
approximately 10.7m  21.3m. This was the first time ferrocement concept in the
applications to building. Later he covered the swimming pool at the Italian Naval
Academy with a 15m-diameter dome and then the famous Turin Exhibition Hall – a
roof system spanning 91m. In both cases, ferrocement served as permanent forms
for the structural system including the main support ribs.
In 1958, the technology then spread to Russia with the construction of a
number of structures. Examples of these were a ferrocement vault of 17.0m spans in
one of the metro stations in Leningrad and the interior of a hall covered with
ferrocement elements.
The more recent ferrocement structures include the Sydney Opera House,
built in 1973. Ferrocement tiles were used as surfacing on the vaults of the Opera
House, a major arts centre in Sydney. Similar beautiful buildings and mosque were
built in India and Indonesia using ferrocement.
2.3
Advantages of Ferrocement/Ferrogrout
Ferrocement is particularly suited to developing countries for the following
reasons:

Its basic raw materials are available in most countries.

It can be fabricated into almost any shape to meet the needs of the user;
traditional designs can be reproduced and often improved.
9

For properly fabricated, it is more durable than most woods and cheaper than
imported steel, and it can be used as a substitute for these materials in many
applications.

The skills required for ferrocement construction are quickly acquired, and
include many skills traditional in developing countries. Ferrocement
construction does not need heavy plant or machinery; it is labour intensive.
Being labour intensive, it is relatively inexpensive in developing countries.
Except for sophisticated and highly stressed designs, as those for deepwater
vessels, a trained supervisor can achieve the requisite amount of quality
control using fairly unskilled labour for fabrication.

In case of damage, it can be repaired easily.
The beauty of ferrocement was that it could appear in any shapes. Only
imagination could limit the forms and shapes of this beautiful and cheap material.
Further unskilled labour could be employed to construct the structure. The material
and labour required are plentiful in the developing countries, especially in rural
areas. These factors make it a very appropriate material for national developments.
2.4
Constituent Materials
Ferrocement can be divided into two main components: the matrix and the
reinforcement.
2.4.1
Matrix
The matrix is a hydraulic cement binder, which may contain fine aggregates
and admixtures to control shrinkage and set time, and increase its corrosion
resistance. The binder is itself a composite material consisting of a hydrated cement
paste and an inert filler material.
10
2.4.1.1 Cement
The cement commonly used is Portland cement possibly blended with
pozzolan. The cement should comply with ASTM C 150-85a, ASTM C 595-85, or
an equivalent standard. The cement should be fresh, of uniform consistency and free
of lumps and foreign matter. It should be stored under dry conditions and for a short
duration as possible. Cement factors are normally higher in ferrocement than in
reinforced concrete.
Mineral admixtures, such as fly ash, silica fumes or blast furnace slag may be
used to maintain a high volume fraction of fine filler material. Filler material is
usually well-graded sand and this classifies the binder material as a mortar. Since the
matrix represents approximately over 95% of the resulting ferrocement volume, its
physical properties and microstructure, which depend upon the chemical composition
of the cement, the nature of the inert filler, the water-cement ratio and the curing
regime, have a great influence on the final properties of the product.
Rice Husk Ash (RHA) cement can be economically used as partial
replacement of cement in mortar mixes. When RHA does not exceed 35% by weight
of the blended cement, the compressive strength at 28 days is similar to that of Type
I Portland Cement Mortar.
The reaction of Portland cement and water results in formation of hardened
cement paste. The ranges of mix proportions recommended for common
ferrocement applications are sand-cement ratio by weight, 1.5 to 2.5, and watercement ratio by weight, 0.35 to 0.5. Fineness modulus of sand, water-cement ratio
and sand-cement ratio should be determined from trial batches to insure a mix that
can infiltrate (encapsulate) the mesh and develop a strong and dense matrix. Water
reducing admixtures may be used to enhance mix plasticity and retard initial set, as
with conventional concretes. The behaviour of mortar is similar to that of plain
concrete. The major distinction is the size of the aggregate used. In general a good
quality mortar is stronger and more durable than good quality concrete; however,
their basic response to the environment is essentially the same.
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2.4.1.2 Fine Aggregates
Normal weight fine aggregate (sand) is the most common aggregate used in
ferrocement. It should be clean, hard, strong, and free of organic impurities and
deleterious substances and relatively free of silt and clay. It should be inert with
respect to other materials used and of suitable type with respect to strength, density,
shrinkage and durability of the mortar made with it. Grading of the sand is to be
such that a mortar of specified proportions is produced with a uniform distribution of
the aggregate, which will have a high density and good workability and which will
work into position without segregation and without use of a high water content. The
fineness of the sand should be such that 100% of it passes standard sieve No. 8.
Table 2.1 gives some guideline on desirable grading.
Table 2.1: Guideline on desirable sand grading
Sieve Size
Percent Passing
No. 8
80-100
No. 16
50-85
No. 30
25-60
No. 50
10-30
No. 100
2-10
2.4.1.3 Admixture
Chemical admixtures used in ferrocement serve one of the following four
purposes: water reduction, which increases strength and reduces permeability; air
entrainment, which increases resistance to freezing and thawing; and suppression of
reaction between galvanised reinforcement and cement.
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2.4.2
Reinforcement
The reinforcement of ferrocement is commonly in the form of layers of
continuous mesh fabricated from an assembly of continuous single strands filaments.
Specific mesh types include woven and welded mesh, expanded metal lath and
perforated sheet products. There is a wide variety in mesh dimensions, as well as in
the amounts, sizes and properties of the materials used.
2.4.2.1 Wire Mesh
Wire mesh is one of the essential components of ferrocement. Different types
of wire meshes are available almost everywhere. These generally consist of thin
wires, either woven or welded into a mesh, but the main requirement is that it must
be easily handled and, if necessary, flexible enough to be bent around sharp corners.
The function of the wire mesh and reinforcing rod in the first instance is to act as a
lath providing the form and to support the mortar in its green state. In the hardened
state its function is to absorb the tensile stresses on the structure, which the mortar on
its own would not be able to withstand. A structure is subjected to great deal of
pounding, twisting and bending during its lifetime resulting in cracks and fractures
unless sufficient steel reinforcement is introduced to absorb these stresses. The
degree to which this fracturing of the structure is reduced depends on the
concentration and dimensions of the embedded reinforcement. The mechanical
behaviour of ferrocement is highly dependent upon the type, quantity, orientation and
strength properties of the mesh and reinforcing rod. Figure 2.1 shows the common
type of wire mesh used in ferrocement industry.
The ACI committee 549 on Ferrocement concluded that the definition of
ferrocement could not be limited to steel reinforcing only. The ACI definition of
ferrocement included the statement “Mesh may be made of metallic material or other
suitable materials.” This definition allows bamboo mesh and mesh made of other
materials to be used for ferrocement structures.
13
Figure 2.1: Mesh types commonly used in ferrocement.
2.4.2.2 Skeletal Steel
Skeletal steel as the name implied is generally used for making the
framework of the structure upon which layers of mesh are laid. Both the longitudinal
and transverse rods are evenly distributed and shaped to form. The rods are spaced
as widely as possible up to 300mm apart where they are not treated as a structural
reinforcement and are often considered to serve as spacer rods to the mesh
reinforcements. In some cases skeletal steel is spaced as near as 75mm centre-to-
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centre thus acting as a main reinforcing component wire mesh in highly stressed
structures, for example boat, barges, tubular sections, and others.
Steel rods of different kinds are used in ferrocement construction. Their
strength, surface finish, protective coating and size affect their performance as
reinforcing members of the composite. In general, mild steel rods are used for both
longitudinal and transverse directions. In some cases high tensile rods and
prestressed wires and strands are used. Rod size varies from 4.20mm to 9.5mm
whereas 6.35mm is the most common. Ferrocement panels with longitudinal and
transverse rods of this size are about 25mm. A combination of different rod sizes
can be used with smaller diameter rod in the transverse direction.
2.4.2.3 Substitute Materials
Some of the substitute materials include bamboo mesh and bamboo skeletal
reinforcement. Chembi and Nimityongskul (1989) investigated the use of bamboo
mesh to replace steel wire mesh in ferrocement water tank. A bamboo cement tank
of 6m3 capacities was constructed in 1983. The tank was kept alternatively full and
empty of water to simulate actual field condition and was monitored regularly. After
5 years, they found that the tank has not shown structural defects. Bamboo
reinforcement 0.3 m from the top of the tank was investigated and found in good
condition.
Meanwhile, Venkateshwarlu and Raj (1989) investigated the use of bamboo
to replace skeletal steel in ferrocement roofing elements. Slabs reinforced with
bamboo strips as skeletal reinforcement and chicken wire mesh were subjected to
monotonically increasing uniformly distributed load to study the load deflection
behaviour and to determine its serviceability limit (span/deflection). The
investigation showed that by using bamboo, the cost of roofing elements comes to
about 50% of reinforced concrete and 70% of ferrocement elements. The slabs can
be prefabricated in the factory or can be produced at the site manually. The
serviceability limit was suggested as 150 and it was observed, that at deflections up
to 10mm, no cracking occurred. Hence, roofing elements can be produced up to a
maximum span of 1.5m and can be used in multiples to cover longer span.
15
2.4.3
Other Materials
2.4.3.1 Water
Water used in the mixing is to be fresh and free from any organic and harmful
solution, which will lead to deterioration in the properties of the mortar. Salt water is
not acceptable but chlorinated drinking water can be used. Potable water is fit for
use as mixing water as well as for curing ferrocement structures.
2.4.3.2 Coating
In general, ferrocement structures need no protection unless they are
subjected to strong chemical attack that might damage the structural integrity of their
components. A plastered surface can take a good paint coating. In terrestrial
structures, ordinary paint is applied on the surface to enhance the appearance.
Marine structures need protection against corrosion and vinyl and epoxy coatings
were found to be the most successful organic coatings.
2.5
Properties
Ferrocement, often regarded as just another form of reinforced concrete, is
quite unique with respect to material behaviour and suitability for structural
applications. Ferrocement possesses a degree of toughness, ductility, durability,
strength and crack resistance that it is considerably greater than that found in other
forms of concrete construction. These properties are achieved in structures with a
thickness that is generally less than 25mm, a dimension that is nearly unthinkable in
other forms of concrete construction, and a clear improvement over conventional
reinforced concrete. Some of the properties of ferrocement such as tension,
compression, flexure, shear, fatigue, impact and fire resistance, durability, corrosion,
and water retaining capacity had been investigated and are listed as below.
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2.5.1
Tensile Behaviour
Unlike reinforced concrete, tensile behaviour of ferrocement is considerably
different. This is mainly because the reinforcement is spaced closer and uniformly
than in reinforced concrete and its smaller diameter results in a larger specific surface
area. This in turn affects cracking behaviour (finer and more number of cracks) in
ferrocement.
Naaman and Shah’s (1974) work indicated that the stress level at which the
first crack appeared and the crack spacing were a function of the specific surface of
reinforcement. The ultimate load of the ferrocement specimen was the same as the
load carrying capacity of the reinforcement in that direction. This should be
expected since the load is carried by the reinforcement itself after the mortar is
cracked.
Al-Noury and Huq (1988) had proposed expressions for predicting the first
crack strength and modulus of elasticity of ferrocement in the uncracked and cracked
range. It was found that the first crack strength of ferrocement in tension might be
predicted on the basis of the strain at the limit of proportionality of mortar and the
uncracked modulus of ferrocement. The modulus of elasticity of ferrocement in the
cracked range could be predicted on the basis of the behaviour of an equivalent
composite model aligned wires. Beyond first crack, the crack formation mechanism
in ferrocement in the cracked range is related to the matrix-wire interfacial bond.
2.5.2
Compression Strength
The high compressive strength of mortar contributes primarily to the
compressive strength of the ferrocement composite. Although the reinforcement
may have some influence on the compressive strength, but this is limited to certain
types of reinforcement. For example, the use of welded wire mesh would increase
compressive strength due to the lateral restraint provided by the welded transverse
17
wires, while the hexagonal mesh or expanded metal may weaken the composite due
to longitudinal splitting.
Kameswara Rao and Kamasundra (1986) investigated the stress-strain curve
and Poisson’s ratio of ferrocement in axial compression. It was found that the
specific surface is the only factor, which controls the behaviour of ferrocement in
axial compression. Equations developed for predicting the increase in strength,
strain and modulus of elasticity by regression analysis were used to generate the
stress-strain curve of ferrocement under axial compression. They have found that
ferrocement behaves linearly up to 50-60% of the ultimate strength in compression;
beyond this limit the behaviour becomes non-linear. The value of ultimate strength,
strain at ultimate strength and Young’s modulus increase with increasing of specific
surface area.
2.5.3
Flexural Strength
In some application, ferrocement may be subjected to flexural stress. In such
cases, one must consider the method and manner in which its behaviour in flexure
may be predicted. Needless to say that compared an average reinforced concrete
beam (which is generally under-reinforced), the ferrocement beams due to several
layers of wire mesh tend to be over reinforced. It is therefore important to insure that
indeed ferrocement will not fail similarly to an over-reinforced concrete beam.
Analytical and experimental evaluations were reported by Johnston and Mowat
(1974), Logan and Shah (1973), Balaguru et al (1976) and Pama et al (1978).
Mansur and Paramasivam (1986) proposed a method to predict the ultimate
strength of ferrocement in flexure based on the concept of plastic analysis where
ferrocement is considered as a homogenous perfectly elastic-plastic material. Simple
equations are derived for direct design of a cross-section. An experimental
investigation was also conducted to study the behaviour and strength of ferrocement
in flexure. It was found that the ultimate moment increase with increasing matrix
18
grade (decreasing water cement ratio) and increasing volume fraction of
reinforcement.
2.5.4
Shear
Venkata Krishna and Basa Gouda (1988) performed testing on ferrocement
beams with different volume fraction of reinforcement in transverse shear. It was
found that the shear strength depends upon mortar, strength of wire mesh, volume
fraction and shear span. Theoretical expressions were developed for predicting the
shear strength at first crack and collapse of ferrocement beams with different type of
wire meshes namely hexagonal, woven and welded.
2.5.5
Fatigue Resistance
Fatigue strength plays an important role in restricting the use of ferrocement
in structures subjected to such a loading as in bridges. The fatigue strength of the
wire, as tested in air, is the primary factor affecting fatigue of the composite.
Balaguru et al (1977) investigated the flexural fatigue properties of ferrocement
beams reinforced with square woven and welded meshes. Their finding is the
relationship between the stress range in the outermost layer of steel mesh and the
number of cycles to failure.
Singh et al. (1986) investigated the influence of the reinforcement on the
fatigue behaviour of ferrocement. They conducted fatigue tests on ferrocement slabs
with different types of mesh reinforcement, studying the effect of the size of wire,
galvanising of the wire and placing of wire mesh in layers to the fatigue strength of
ferrocement. Samples of the wires were also fatigue-tested in air and a relationship
is developed between the fatigue strength of each type in air and in the composite. It
was found that the fatigues of the wire in air and in ferrocement are related. Most
19
fatigue failures occurred by fracture of the wires and the range of repeated stress in
the wires gave the greatest on the fatigue strength of ferrocement.
2.5.6
Impact Resistance
Impact strength is a useful parameter in applications related to offshore
structures and boats. Reports attesting the favourable characteristics of ferrocement
in collisions involving boats with each other or with rocks are numerous. The main
attributes include resistance to disintegration, localisation of damage, and ease of
repair. However, due to experimental complexity associated with measurement of
impact resistance, little quantitative or comparative data exist.
Impact strength was defined as the energy absorbed by the specimens when
struck by a swinging pendulum dropped from a constant height. The damage was
measured by the relative flow of water through the specimen surface for a fixed
energy absorbed which is 600lb-in (66.7kN-mm).
Shah and Key (1972) tested 9in2 (5625mm2) and ½in (12mm) thick
ferrocement slabs using an impact tester. From the test, it indicated that the higher
the specific surface of the meshes and the higher the strength of the mesh, the lower
the damage due to impact loading.
2.5.7
Fire Resistance
A problem unique to ferrocement is potentially poor fire resistance because of
the inherent thinness of its structural form and the abnormally low cover given to the
reinforcement.
Basanbul et al. (1989) studied the fire resistance of ferrocement load bearing
sandwich panels. The fire resistance of the ferrocement wall was found to be
20
encouraging for designers of ferrocement buildings. Though the thin shell nature of
ferrocement has raised questions about its fire resistance, it was found that
ferrocement retains much of the load bearing qualities of reinforced concrete. Its
heat transmission qualities are not as good as those of reinforced concrete, which
would be just under four hours, but this latter consideration is more dependent on the
mass of the wall. Limited problems of spalling of the front face sheets occurred
during the early portion of the test but this spalling was not severe enough to cause
serious structural damage during the period in which the wall satisfied the ASTM E119 performance criteria.
2.5.8
Durability
When ferrocement is exposed to aggressive environment, its successful
performance depends to a great extent on its durability against the environment than
on its strength properties. The external causes may be physical, chemical or
mechanical. They may be due to weathering, occurrence of extreme temperatures,
abrasion, electrolytic action, and attack by natural and industrial liquids and gases.
The extent of damage produced by these agents depends largely on the quality of the
mortar, although under extreme conditions any unprotected mortar will deteriorate.
The internal causes are alkali-aggregate reaction, volume changes due to the
differences in thermal properties of aggregate and cement paste, and above all the
permeability of mortar. The permeability of mortar largely determines the
vulnerability of the mortar to external agencies, so that in order to be durable the
mortar must be relatively impervious.
Although the measures required to insure durability in reinforced concrete
also apply to ferrocement, three other factors which affect durability are unique to
ferrocement. First, the cover is small and consequently it is relatively easy for
corrosive liquids to reach the reinforcement. Second, the surface area of the
reinforcement is unusually high, so the area of contact over which corrosion
reactions can take place, and the resulting rate of corrosion, are potentially high.
Third, although many forms of reinforcement used in ferrocement are galvanized to
21
prevent corrosion, the zinc coating can have certain adverse effects bubble
generation. All three factors have varying importance depending on the nature of the
exposure condition. However, in spite of these unique effects, there is no report of
serious corrosion of ferrocement not associated with poor plastering or poor matrix
compaction. To insure adequate durability in most applications, a fully compacted
matrix is necessary. A protective coating may also be desirable.
2.5.9
Corrosion
Corrosion is the deterioration of metals or alloy due to interaction with its
surroundings. The most common example of corrosion is the rusting of steel.
Corrosion is normally a fairly slow but complex process; however, due to presence
of certain conditions, it may occur very rapidly. Many of these can occur in
ferrocement and avoiding them is one of the biggest problems. All ferrocement
marine structures, by virtue of their marine environment are liable to corrosion
attack. The danger of corrosion is enhanced in ferrocement by the extreme thinness
of the cover of mortar over the steel reinforcement. The corrosion process is often
difficult to recognise until extensive deterioration has occurred. The severity of the
attack on structure will depend basically on how well it has been designed and built,
the materials used and what happens to it when in and out of use.
2.5.10 Water (or Liquid) Retaining Capacity
Another special property to be noted is that of water retention when
application of ferrocement is considered in liquid storage tanks. The important
aspect here is small crack widths so that leakage may be minimal. Shah and Naaman
(1977) indicated that crack widths in ferrocement for the same steel stress are smaller
than in reinforced concrete by order of magnitude. This making it a better choice on
material for water retaining structures. Tests were conducted on cylindrical vessels
with internal water pressure to investigate this impact. The results showed that the
22
crack width in ferrocement is much smaller than allowable. Naaman and Sabins
(1978) also provided some recommendations on using ferrocement for water tanks.
2.6
Construction Procedure
Ferrocement construction unlike other sophisticated engineering construction
requires minimum of skilled labour, utilises readily available materials and most of
the tools for construction are intended for conventional concrete construction. The
skills for ferrocement construction techniques are easily acquired and requisite
quality control can be achieved using fairly unskilled labour for the fabrication under
the supervision of a skilled foreman.
There are several means of producing ferrocement. All methods require
high-level quality control criteria to achieve the complete encapsulation of several
layers of reinforcing mesh by a well-compacted mortar of concrete matrix with a
minimum of entrapped air. The most appropriate fabrication technique depends on
the nature of the particular ferrocement application; the availability of mixing,
handling and placing machinery; and skill and cost of available labour.
The four major steps in ferrocement construction are:

Placement of wire mesh in proper position,

Mortar mixing,

Mortar application, and

Curing.
The objective of all construction methods is to thoroughly encapsulate a
layered mesh system with a plastic Portland cement matrix. The mortar must be
thoroughly compacted during placing to ensure the absence of voids around
reinforcement and in the corners of any framework. Ferrocement structures are to be
properly cured once the mortar has taken its first set (which occur 3 to 4 hours after
mortar application). The set mortar or concrete is to be kept wet for a period
dependent on the type of cement used and the ambient conditions.
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2.7
Applications
2.7.1
Housing Applications
Ferrocement has found widespread applications in housing particularly in
roofs, floors, slabs and walls. Ferrocement is considered as a suitable housing
technology for developing countries attested by the increasing number of easily built
and comfortable ferrocement houses. Ferrocement houses utilising local materials
such as wood, bamboo or bush sticks as equivalent steel replacement have been
constructed in Bangladesh, Indonesia and Papua New Guinea.
Precast ferrocement elements have been used in India, the Philippines,
Malaysia, Brazil, Papua New Guinea, Venezuela and the Pacific for roofs, wall
panels and fences. In Sri Lanka, a ferrocement house resistant to cyclones has also
been developed and constructed. A pyramidal dome over a temple in India and
numerous spherical domes for mosques in Indonesia have been constructed with
ferrocement. The choice was dictated by low self-weight, avoidance of formwork
and availability of unskilled labour. Figure 2.2 shows one of the examples of the
houses built using ferrocement structures.
Figure 2.2: A typical ferrocement house
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2.7.2
Marine Applications
Ferrocement has been adapted to traditional boat designs in Bangladesh,
China, India, Indonesia and Thailand due to timber shortages. In China, 600
ferrocement boat-manufacturing units produce annual capacity of 600,000 to 700,000
tonnages. Ferrocement boats are divided into four categories according to usage:
farming boats, fishing boats, transport boats and working boats.
In countries like Hong Kong, Korea, India, Malaysia, Philippines, Sri Lanka
and Thailand, ferrocement boats generally conform to western standards. In Hong
Kong, India and Sri Lanka, most of the ferrocement crafts constructed are used as
mechanised fishing trawlers while in Korea, as fishing boats. In addition, the
Southeast Asian Fisheries Development Centre, Philippines, has used ferrocement
tanks for prawn brood stock and ferrocement buoys for a floatation system in the
culture of green mussels. This is the first large-scale use of ferrocement for these
purposes.
In Africa, ferrocement boatyards have been successfully established in
Kenya, Sudan and Malawi. The boatyards are now self-supporting under the
management of local staff trained by the consultants. The objective of these
boatyards is to provide rural fisherman opportunities to explore the fishable grounds
to increase their income. Figure 2.3 shows a ferrocement boat under constructions;
meanwhile Figure 2.4 shows a typical ferrocement boat.
Figure 2.3: A ferrocement boat under constructions
25
Figure 2.4: A typical ferrocement boat
2.7.3
Agriculture Applications
Agriculture provides the necessary resource for economic growth in
developing countries. The use of ferrocement technology can contribute towards
solving some of the production and storage problems of agricultural produce.
Ferrocement has been used for grain storage bins in Thailand, India and Bangladesh
to reduce losses from attack by birds, insects, rodents and moulds.
Thailo, a conical ferrocement bin; was designed and first constructed at the
Asian Institute of Technology (AIT), Bangkok, Thailand. Storage capacities range
from 1 to 10 tons. This bin has proved to be structurally sound and construction has
provided adequate protection to the produce against rodent, insect and bird attacks.
The bin costs well within the means of the farmers. Besides, this type of silo also
can hold up to 5000 gallons (22.7m3) of drinking water.
In Ethiopia, underground pits are the traditional method of grain storage. It
has been found that when the traditional pit is lined with ferrocement and provided
with an improved airtight lid, a hermetic and waterproof storage chamber can be
achieved.
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2.7.4
Water and Sanitation Applications
Ferrocement can be effectively used for various water supply structures like
well casings for shallow wells, water tanks, sedimentation tanks, slow sand filters
and for sanitation facilities like septic tanks, service modules and sanitary bowls.
Some findings indicated that ferrocement tanks are less expensive than steel or
fibreglass tanks. The reasons why ferrocement is cheaper are:

Ferrocement is an feasible material for the construction of water storage

Flexibility of shape, freedom from corrosion, possibility of hot storage,
relative lack of maintenance, and ductile mode of failure are important
advantages of ferrocement over other materials

Ferrocement tanks require less energy to produce than steel tanks.
Ferrocement water tanks of 20 to 2000 gallons (0.09 to 9m3) capacity are
mass-produced in India. Bamboo-cement well casings have been built in Indonesia
to prevent contamination of the water.
2.7.5
Miscellaneous Applications
Ferrocement is proving to be a technology that can respond to the diverse
economic, social and cultural needs of man. Ferrocement has been used to
strengthen older structures, a medium for sculpture and for many other types of
structures. Ferrocement as a medium for sculpture proves its versatility and the
unlimited dimension to which it can be used. Ferrocement in art is an exciting
development and it open new horizons. Figure 2.5 shows a typical sculpture made
from ferrocement.
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Figure 2.5: A typical ferrocement sculpture
Universiti Teknologi Malaysia (UTM), Skudai, Malaysia also gained some
experiences in constructing the prefabricated and landscaping objects. The objects
done by Mohd. Warid Hussin, Abdul Rahman Mohd. Sam, and the staff from
Structural and Material Laboratory, Faculty of Civil Engineering are:

Garden and outdoor furniture

Decorative mushroom

Fascia

Sidewalk slab

Sun Screen/shade

Ferrocement canoe
Some of these objects are still well in condition and can be found within the
area of the laboratory. Figure 2.6 shows the ferrocement objects in UTM.
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a: Sunshade and irrigation canal
b: Canoe
lining
c: Chairs and table
d: Mushroom
Figure 2.6: Some of ferrocement objects that can be found in UTM
2.8
Conclusion
Ferrocement has gained widespread use and acceptance, particularly in
developing countries and has already attained worldwide popularity in almost all
kinds of applications: marine, housing, water resources and sanitation, grain and
water storage, biogas structures, and for repair and strengthening of structures.
Widespread use of ferrocement is evident in countries like China, Russia, India,
Cuba, South East Asia and others.
There are several reasons for its widespread use. On the construction side, it
can be fabricated into almost any shape, skill needed for the construction can be
easily acquired, heavy plant and machinery is not required and easy to repair.
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Meanwhile, on the material side, ferrocement possesses a degree of toughness,
ductility, durability, strength and crack resistance that is considerably greater than
that found in other forms of concrete construction.
However, there are still areas of applications where ferrocement is not widely
used, such as structural components, like main beam, column, etc. This may be due
to insufficient understanding on the behaviour of ferrocement. Hence, more
researches still have to be done. This present research will contribute to the
enrichment of information and understanding on this subject.