Bendable Concrete: A Study on PVA Fibres and Superplasticizer in Engineered Cementitious Composites

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BENDABLE CONCRETE
Student’s Name
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Project summary
Bendable concrete is a mortar-like that is
easily moulded composite that is
reinforced particularly with short random
fibres. The traditional concrete experiences
a great failure as a result of being strained
in an earthquake or by a routine overuse,
compared to the bendable concrete which
keeps its tensile strength of up to 5%
remaining intact and safe. Traditional
concrete cannot sustain a weight of 0.01%
tensile strain. To address the future
demand for concrete and to develop fibre
materials in this paper, PVA is used in
order to lower the amount of cement and
improve the flexibility of the concrete. It
contains high aspect ratio, better water
affinity, and ultimate high tensile strength,
no risks to health, relatively high elasticity
modulus.
Keywords: PVA fibres, superplasticizer,
ECC
Introduction
Background
Conventional concrete nearly does not
have bendability features having a strain
capacity of 0.01% that results in their high
brittleness and rigidity. Its lack of
bendability characteristics is the major
leading result to failure when exposed to
strain. This has pushed for the need to
design an elegant component called
Engineered Cementitious Composites.
This material is able to exhibit
considerably a suitable flexibility. The
polymer fibres reinforced in bendable
concrete are micro-chemically designed
whereas ECC is achieved from basic
ingredients that are the same as of the ones
for the conventional concrete. Although it
contains High Range Reducing agents that
are added to it so as attain a good
workability. There is no usage of coarse
concrete in ECC hence, it is instead a
mortar, not concrete.
[1].
Objectives of the research
 To check the ECC nature under
split tensile test, compression and
flexural test.
 To obtain the deflection of ECC
beams.
Significance
This ECC is more flexible than the
traditional concrete it is therefore seen as a
metal as compared to glass. Traditional
concrete is deemed to ceramic brittle and
rigid. It can experience a catastrophic
failure if under strain and by routine
overuse. It is studded with reinforcements
of especially fibre coatings that keep it
together. This ensures that the ECC even at
5% tensile strength it is still intact and
safe. Traditional concrete fractures will not
be able to sustain a tensile strain load of
0.01%.
Nowadays constructors of buildings
reinforce concrete structures with steel
bars just in any case cracks will show up,
they would exist as micro-cracks. It is
unfortunate as the cracks would not be that
small to adequately heal. Water and
deicing salts that penetrate through the
concrete and to the steels leads to
corrosion of the steel which in return
weakens structures. This concrete with
self-curing feature may not corrode
because it does not need steel
reinforcements in order for the concrete to
retain the width of the cracks intact [6].
Definitions
PVA fibre – Polyvinyl Alcohol fibre

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Permeability – Rate of flow of fluid
through porous media. In this case, flow
through concrete.
Self-healing – Process of filling the micro-
cracks in concrete by the occurring internal
reactions.
Durability – The ability of concrete to
sustain strain imposed on it.
Workability – The ease of compaction,
transportation and mixing of concrete.
ECC – Engineered Cementitious
Composite.
Literature review
[2]Carried out a research on steel and
synthetic fibres both commercially
available. The relationships between
flexural and deflection stress are used to
obtain flexural strength and the ratio of
equal flexural strength. The flexural
toughness of the concrete revealed in
having increased averagely upon the use of
steel and synthetic fibres. However, the
same dosage of various fibres did not lead
to similar flexural toughness in the
specimens.
[3] Performed an investigation that
experimented on the flexural feature of
self-compact concrete that is reinforced
with hooked-end and straight end steel
fibres levelling 1.5%, 0.5% and 1.0% in
comparison with Normally Vibrated
Concrete. Tests from the laboratory were
to be acquired in accordance with the
recommendations of RILEM TC 162-TDF.
Normally Vibrated Concrete had similar
SCC flexural features. This because an
increase in the fibres volume ratio resulted
in an increase in the pre-peak and post-
peak parameters of SCC. The kind of steel
fibres to large extent influenced the
dependency. Therefore, the SCC attains
the greatest displacement in the crack
mouth for least deflections than the
Normally Vibrated Concrete.
[4]Conducted an experiment on the likely
applications of ECC that is reinforced with
fibres with features of less drying
shrinkage in the concrete’s pavements to
achieve elimination of the joint that
usually accommodates deformation of
temperature and shrinkage. It was
discovered that composite slab containing
both LSECC and conventional concrete
with steel bars at the interface of LESS or
concrete as well as procedures that have
been designed for construction, would lead
to localization of the tensile cracks into the
LSECC strips. This would prevent
cracking in the adjacent slabs.
[5]Researched on the self-healing
characteristic of the LESS to study the
impact of pre-cracking time and curing
conditions. The ECC beams were pre-
cracked using four-point bending at a
varied age, then by different curing
conditions. For all curing conditions, self-
curing and capacity to deflect would even
recover or exceed those of virgin samples
at each pre-cracking stage.
Methodology
Ingredients of bendable concrete
Sand
Sand s used in making of mortar and
concrete as well as polishing and
sandblasting. The sands with fewer
contents of clay are used in making of
moulds in foundries. The sands weight
changes from 1,538 - 1842kg/m3 basing
on the grains size and composition. The
passing through of the fine aggregate in
4.75mm sieve having 2.68 special gravity
is usually used [7].
Cement
The cement which is normally used is the
Ordinary Portland Cement. The definition
of cement is as, the several organic
compounds used for adhering and
fastening of materials. The furnace blast is