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International Journal of Engineering & Technology, 7 (4.20) (2018) 449-452
International Journal of Engineering & Technology
Website: www.sciencepubco.com/index.php/IJET
Research paper
Possibility of Using Concrete Reinforced by Carbon Fibre
in Construction
Nada Mahdi Fawzi Aljalawi1*, Haider M.K. Al-Jelawy2
1University of Baghdad, civil engineering department
2 Uruk University
* Corresponding author E-mail: naljalawi@yahoo.com
Abstract
This work focuses on studying the mechanical characteristics of carbon fibre reinforced concrete, containing a different percentage of fibre.
This work was carried out using several tests. These tests were hardened density, compressive strength, flexural strength . Tests were
performed for specimens at ages of (7,28,60) days. The test results indicated that the inclusion of fibre in the reference concrete mixes did not
affect the compressive strength significantly, while the flexural strength was improved. Test results indicated that the flexural strength of
(0.75%) carbon fibre concrete specimens are twice that of the reference specimens in age of 28 days . The percentage of increasing the
flexural strength for carbon mixes containing fibre by volume fraction of (0.5%, 0.75%) were (23%, 27%) respectively at age of 28 days.
Keywords: carbon fiber; compressive strength; flexural strength; reference specimens; density.
1. Introduction
Concrete is a composite material made from a filler which
represented by the coarse granular material firmed in matrix which
represented by the cementitious materials (the binder). The binder
will fill the spaces between the filler particles and bond them
together. However, it is a weak material having low rigidity and
low strain ability that effect its tensile strength. For this purpose,
fibre reinforced concrete(FRC)was created. Fibres help with
enhancing is better ductile strength, flexural strength, toughness
furthermore effect the concrete quality positively [1,2,3].
This study focuses on the effect of carbon fibre on the properties of
concrete. Moreover, carbon fibres have low density , particularly
compared with steel fibre. Their strength-to density proportion is the
highest amongst those most elevated fibres types. Carbon fibres have
a higher quality compared to metallic fibres. This motivation was
behind their utilization to produce composite materials with good
properties such as polymeric composites. [4].
1.1. Concrete Reinforced by Carbon Fibre
Carbon fiber concrete framework composites are auxiliary materials
that are picking up in significance quickly because of the abatement
in carbon fiber cost and the expanding request of unrivaled basic and
practical properties. These composites contain short carbon
filaments, ordinarily 5 mm long, as the short strands can be utilized
as an admixture in cement (while constant strands can't be
essentially added to the solid blend) and short filaments are more
affordable than persistent filaments. Be that as it may, because of the
frail bond between carbon fiber and the bond network, consistent
filaments are significantly more compelling than short strands in
fortifying cement.
The impact of carbon fiber expansion on the properties of solid
increments with fiber volume portion, except if the fiber volume
division is high to the point that the air void substance turns out to be
too much high (The air void substance increments with fiber
substance and air voids will in general negatively affect numerous
properties, for example, the compressive quality).
The enhanced auxiliary properties rendered via carbon fiber
expansion relate to the expanded malleable and adaptable qualities,
the expanded tractable flexibility and flexural strength, the upgraded
effect obstruction, the decreased drying shrinkage and the enhanced
stop - defrost sturdiness.
The ductile and flexural qualities diminish with expanding example
estimate, to such an extent that the size impact winds up bigger as
the fiber length increments . The low drying shrinkage is profitable
for extensive structures and for use in fix and in joining blocks in a
block structure [5].
2. Literature Survey
This literature review will be limited to research of FRP material
externally bonded to the tensile face of concrete beams. In particular,
research studying the effect of externally applied FRP materials on
the flexural performance of reinforced concrete beams will be
reported.
Triantifillou and Plevris (1991) used strain compatibility and
fracture mechanics to analyze reinforced concrete beams applied
with externally bonded carbon fiber reinforced plastics (CFRP). The
International Journal of Engineering & Technology
450
same assumptions as An et al. They were used with the inclusion of
an rectangular compression stress distribution in the concrete at
failure. [6].
Wasan I. Khalil and Akar Abdulrazaq: They mulled over those
mechanical properties about high performance carbon fiber cement
would contemplated. The test fill in includes, transforming
secondary execution cement utilizing superplasticizer Furthermore
condensed silica fume strengthened with diverse volume portions
(0%, 0. 2%, 0. 3%, 0. 4% and 0. 5%) about carbon fibers. Those
impact about hacked carbon fibers on the mechanical properties
(compressive strength, Part ductile Furthermore flexural strengths,
Furthermore modulus of elasticity) for high performance cement
might have been likewise examined. Generally, those Outcomes
indicate that s were as from claiming carbon fibers enhances the
mechanical properties of high performance cement. Likewise the
Outcomes indicate that utilizing condensed silica fume concerning
illustration proportion by weight about bond expands the
compressive quality more than that concerning illustration
supplanting replacement of weight cement. [7].
E. Mello, C. Ribellato and E. Mohamedelhassan: They investigated
progress properties for concrete about cellulose, steel, carbon and
PET fibers. Every fiber might have been included at four rates of the
new concrete, which might have been moist-cured to 28-days et
cetera tried for compressive, flexural Furthermore pliable qualities.
Progressions clinched alongside quality What's more increments to
expense were investigated. Effects demonstrated that expansion
about cellulose acetic acid derivation created a diminish between 9.
8% Also 16. 4% On compressive quality. This extend might be
worthy Likewise cellulose acetic acid derivation fibers could
fundamentally expand those cement safety should fire, and
solidifying Also defrosting cycles. Carbon fibers improve flexural
Furthermore tensile qualities eventually up to 11% What's more
45%, individually. Cement properties diminished then after addition
fibers. Outcomes demonstrated that change in quality following
expansion for steel and carbon fibers might defend the additional
expense from claiming fibers[8].
S. M. Kinayekar , V. D. Gundakalle and Kishor Kulkarni: High
Quality Cement (HSC)is thick, homogeneous and has the enhanced
building properties and sturdiness as customary cement. Lately, HSC
has increased wide application in the development business. High
quality Cement is a solid having comparable fixings as customary
concrete, for example, bond, fine total, coarse total and water. The
glue of HSC requires high volume of concrete substance and less
water to powder proportion. The soundness and stream capacity of
HSC is finished by expanding the powder substance or work of
powder admixtures. In any case, expanding the bond content reason
surprising expense, higher warmth of hydration and higher drying
shrinkage. This can be decreased by work powder admixture, for
example, fly cinder and ground granulated impact heater slag and so
forth. In the present examination, concrete substance for H.S.C blend
is substitute with steady % of fly slag (10%) and carbon fiber are
included vol. section (0 to 0.60%), additionally the carbon Fiber
Strengthened Polymer (CFRP) turf are put in different layer (single,
twofold and triple layer) with adjust width of CFRP strip (0 to 80
mm). The sustained solid properties of HSC were contemplated and
the relapse examination was completed on the trial examination.
The investigation reasons that carbon filaments can be successfully
utilized as a strengthening material in HSC[9].
Qais Hassan Fadel: He considered contain a test work to discover the
advantage emerges from CFRP (Carbon Fiber reinf. Polymer) covers
expansion to bond mix blend in diminishing the entire warm
conductivity and the warmth exchange through development
components, which increment warm protection and lessen utilization
of power utilized for cooling gear.
Eight solid examples of rectangular cross areas were cast to inspect
the warm conductivity, notwithstanding that a 12 standard solid 3D
squares were set up to discover the compressive quality of cement.
Carbon strands were cut and added with various adds up to get its
impact on warmth exchange and warm conductivity for cement to
contrast it and the compressive quality. Test results for warm
conductivity for testing time of (390) minutes for every example
demonstrated an expansion in warm protection for the reinforced
cement, and this protection increments with expanding measure of
CFRP included. The solid examples and shapes were separated into
four gatherings of various measure of CFRP, which were (0 %, 0.45
%, 1.1 %, 1.6 %) of concrete weight utilized in the blend.
Notwithstanding that, the protection was expanded in the presence of
CFRP, the compressive quality was diminished by (6.4-28.5) %,
while expanding CFRP sum, as for control concrete[10].
3. Experimental Work
3.1. Cement
In this research , Iraqi Ordinary Portland Cement (OPC Type I)
manufactured in the north of Iraq with trade mark of (Al-Mass) was
used . Its physical properties and chemical composition test results
indicate that the adopted cement conforms to the Iraqi specifications
(IQS No.5/ 1984)
3.2. Sand
Characteristic sand supplied from (Al-Mutasim state organization for
development Contracts ) evaluating set zone 2 might have been
utilized to those cement mixes in this worth of effort. Tests were
conveyed out to figure out those gradation , fineness modulus also
sulfate substance , know tests conforms on Iraqi standard ( IQS no.
45/1984 Zone 2).
3.3. Gravel
Round gravel with nominal max. size (5-14) mm might have been
utilized similarly as a coarse aggregate on the whole mixes. It might
have been brought starting with (Al-Nibaee) district. Tests were
conveyed out to determine the gradation, spec. gravity, thickness
what's more sulfate content, constantly on tests fit in with Iraqi
standard ( IQS no. 45/1984).
3.4. Water
Those water utilized to both blending and curing might have been
potable water from those water-supply system framework (tap
water).
3.5. High Performance Concrete Superplasticiser
A high performance super plasticising commercially known as
Flocrete PC200, was used in this research. It is a high strength
concrete super plasticizer admixture dependent upon
polycarboxylate whichever polymers for in length chains
uncommonly intended will empower those water content of the
cement with perform more successfully. Those measurement
proposed eventually the maker is (0. 75 – 2. 5) Liters/100 kg from
claiming powder materials in the blend.
451
International Journal of Engineering & Technology
3.6. Mineral Admixture (Silica Fume)
Silica fume, as characterized in ACI 116R-2000, is “very fine non
crystalline silica prepared over electric bend furnaces similarly as an
by-result of the preparation of natural silicon alternately alloys
holding silicon. ”. Those silica fume, condensed starting with the
gasses escaping starting with those furnaces, need a helter skelter
content about amorphophallus titanum silicon dioxide What's more
comprises for extremely fine round particles normally averaging0. 1
should 0. 2 μm on breadth.
It is a profoundly pozzolanic material that is used to upgrade
mechanical what's more sturdiness properties about cement. It might
be included straightforwardly to cement as a distinct element
alternately to an mix about Portland bond Furthermore silica fume
(ACI 234R-06).
Silica fume need been distinguished similarly as a pozzolanic
admixture that is compelling in upgrading the mechanical properties
to an incredible degree. Eventually Tom's perusing utilizing silica
seethe alongside superplasticizers, it is generally simpler with
acquire compressive qualities of request of 100–150 MPa
Previously, research center. Expansion of silica seethe to cement
enhances those sturdiness about cement through diminishment in the
permeability, refined pore structure, prompting an decrease in the
dispersion for destructive ions what's more diminishes calcium
hydroxide substance which brings about An higher safety should
sulfate attack. The physical properties Furthermore concoction piece
about SF utilized within this fill in conforms of the necessities from
claiming ASTM C1240-05.
3.7. Carbon fiber
Carbon fiber is a synthetic fiber with Levy shape composed of
carbon micro-crystals formed as a result of Tlyev consisting of
acrylic processing distillates oil and coal resin at certain
temperatures. Used in this research carbon-fiber cut short from
producer company (Fosroc Jordan). And properties of fibers used are
shown in the following table.
3.8. Concrete Mix Design
Laboratory experiments were divided into three mixes.The first
mixture included (cement + water + PC200 + sand + gravel), and the
second mixture included (cement + water + PC200 + Silica fume +
sand + gravel) and finally included (cement + water + carbon-fiber +
Silica fume + sand + gravel). Those points of the mixes utilized for
this ponder need aid provided for table 1.
Table 1: Blend proportions utilized through this worth of effort.
Items
M1
M2
M3
Cement Kg/m3
450
450
450
Silica fume kg/m3
-
45
45
Water L/m3
1380
1380
2200
Fine Aggregate Kg/m3
680
680
680
Coarse Aggregate Kg/m3
960
960
960
PC200 L/m3
2
2
2
FRC by vol %
-
0.5
0.75
4. Results and Discussion
4.1. Compressive Strength
The compressive strength values at various ages for all types of HPC
mixes cured in water are presented in Table 2 Also, the relationship
between compressive strength and Fiber Carbon content.
Table 2: Compressive Strength Test Results for all HPC mixes
Mix
Symbol
FRC
7 days
28 days
60 days
M1
0
28
40
48.8
M2
0.5
32
45
54.9
M3
0.75
35
48.7
58
It is seen from Table 2, that the all examples display an expansion in
compressive quality with the advancement of age at constantly
decreasing rate. This expansion in compressive quality is because of
the coherence of bond hydration process which frames another
hydration item inside the solid grid. Likewise, the present containing
(10%) SF has enhance the advancement of solidarity results. This
enhancement is under the impact of silica smoke and fiber , which
has concoction and physical impacts. . The concoction impact is
basically due to the pozzolanic responses between the indistinct
silica in SF and calcium hydroxide (CH) created by the hydration of
bond to frame calcium silicate hydrates (C-S-H). The physical
impact, which can likewise be considered as filler impact, is that SF
particles increment the pressing of the strong materials by filling the
spaces between the bond grains similarly as concrete fills the spaces
between fine totals and fine totals fill the spaces between coarse
totals in cement.
4.2. Bulk Density
The effect of curing ages on various concrete types; the results
demonstrate that the density increases with time of curing for all
types of concrete due to cement hydration and effect of silica fume
and fiber.
It is found from the testing results as shown in Table 3 that the bulk
density of plastic HPC considerably increase when the fiber carbon
increase .
Table 3 : Bulk Density test results for all HPC mixes
Mix
Symbol
Fiber
Carbon
Bulk Density (Kg/ m3 )
7 days
28 days
60 days
M 1
0
2330
2400
2485
M 2
0.5
2400
2450
2495
M 3
0.75
2332
2480
2500
4.3. Flexural Strength (Modulus of Rupture)
The results exhibited a continuous increase in flexural strength for
all type of HPC with increasing curing age and with contain fiber.
This is attributed to both physical actions and chemical effect
(pozzolanic action) of silica fume and fiber which improving
properties of concrete by increased the dense hydrated calcium
silicate in concrete structure , as mentioned previously .
The effect of fiber on flexural tensile strength is shown in Table 4 ,
which indicates that there is an increase in the flexural tensile
strength for all plastic HPC ( M2, and M3), draw an with ref. HPC
(M1).
Table 4 : Flexural tensile strength test results for all HPC mixes
Mix
Symbol
7 days
28 days
60 days
M1
3.1
4.8
5.0
M2
4.0
5.9
6.1
M3
4.8
6.1
6.4
International Journal of Engineering & Technology
452
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