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International Journal of Research and Innovation (IJRI)
International Journal of Research and Innovation (IJRI)STUDY ON
DURABILITY OF CONCRETE WHEN BLENDED WITH
MICRO SILICA AND FLYASH
R.nandini 1, K. Mythili2
1 Research Scholar, Department Of Civil Engineering, Aurora's
Scientific Technological & Research Academy, Hyderabad, India2
Associate Professor, Department Of Civil Engineering, Aurora's
Scientific Technological & Research Academy,Hyderabad,
India
*Corresponding Author: R.nandini, Research Scholar, Department
of CIVIL Engineering, Aurora's Scientific Technological &
Research Academy, Hyderabad, India Published: October 29,
2014Review Type: peer reviewedVolume: I, Issue : II
Citation:R.nandini,(2014) Durability Of Concrete When Blended
With Micro Silica And Fly Ash
INTRODUCTIONGENERAL
Concrete is one of the most extensively use con-struction
materials in the world, with about two billion tons of utilization
worldwide each year. It is attractive in many applications because
it offers considerable strength at a relatively low cost. Con-crete
can generally be produced of locally available constituents, can be
cast in to wide variety of struc-tural configurations, and requires
minimal mainte-nance during service. However, environmental
con-cerns, stemming from high-energy expense and CO2 emission
associated with cement manufacture, have brought pressures to
reduce consumption through the use of supplementary materials.In
general concrete is said to be a very durable one.
But when reinforced concrete structure subjected to severe
environmental conditions its properties are affected adversely
depending on the type of ex-posure. Durability is one the most
important prop-erties to be considered in the design of reinforced
concrete structures exposed to aggressive environ-ments can be
described by two stages: the initiation and the propagation period.
For the exposed to sea water or deicing salts, the initiation
period is defined by the time taken from initial exposure to the
aggressive environment un-til a concentration of reinforcement able
to initiate corrosion, has been reached. However, even though
corrosion of the reinforcement is in progress the structure still
meet the service requirements for several years without high
maintenance costs. The largest economic benefits are obtained by
prolong-ing the initiation period through proper concrete mix
selection, smart structural design and proper on-site placement of
the concrete among others.
In both developed and developing countries recent researchers
amide at the energy conservation in the cement and concrete
industry, focused on the use of less energy intensive materials
such as Fly-ash, slag and natural pozzlolanas. Later some attention
has been given to the use of pozzolana, Micro silica as partial
replacement to Portland cement. Unlike natural pozzolanas and fly
ash, the silica reaction
Abstract
The environment in some concrete structures can become very
acidic due to formation of sulphuric acid con-verted from hydrogen
sulphide by bacterial action. Significant deteriation of concrete
in such harsh environments has been reported world wide.
Deteriotation of sewer system may result in serious problem such as
the loss of ability to transport sewerage, contamaniation of ground
and ground water, excessive ground settelements.
Very high costs are involved with the repair of deteriorated
concrete structures. In the USA, sulphuric acid is responsible for
billoins of dollars of damage to concrete waste water collection
and treatment systems. In the state of south Australia alone an
estimated budjet for maintaining the existing waste water infra
structure is A $ 48 million per anum. Although it has been reported
that some new materials can be more acid resistant such as
concretes using melted sulphur as the binder or high proportions of
polymer modified binders, these materials are too expansive for
most practical applications. Therefore, the research into
improvement of acid resistance of normal concretes is still
attractive. Over the past 20 years the use supplementary
cementitious materials (SCM) in concrete has become very com-mon
due to their technological, economical and environmental benefits.
The use of SCM such as Micro silica and fly ash in concretes has
been found to improve the resistance of concrete sulphuric acid
attack because of the reduced pres-ence of calcium hydroxide, which
is most vunerable to acid attack. Using Micro silica in binary
cement system as partial replacement of ordinary portland cement
was found to be effective in reduciton of acid attack.
In the present investigation, 5% Micro Silica and 15 % Fly Ash
is added by the weight of the cement as additional ingre-dients in
concrete with different water/ binder ratios 0.55, 0.45 and 0.35 of
Ordinary concrete and Ternary concrete mix . The behaviour of this
Ordinary concrete and Ternary concrete mix studied for durablity
properties like % Weight loss, % Loss of Compressive strength and
Durability Factors by the immersion concrete specimens in 5% H2SO4
and 5 % HCl solution for 28 days,90 days and 180 days.
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International Journal of Research and Innovation (IJRI)
involving Micro silica is rapid and therefore, a long curing
period is not necessary.
Pozzolonic Materials:
Pozzolonic materials are finely divided siliceous and aluminous
materials and have little or no cementa-tious value and in the
presence of moisture at or-dinary temperature, chemically react
with calcium hydroxide liberated during hydration, to form
com-pounds possessing cementatious properties. The engineering
benefits likely to be derived from the use of pozzolonas in
concrete include improved re-sistance to thermal cracking because
of lower heat of hydration, enhancement of ultimate strength and
impermeability due to pore refinement, a better du-rability to
chemical attacks such as acid, sulphate, water and alkali-aggregate
expansion.
Types Of Pozzolonas:
Pozzolonic materials can be divided in to two Types
1.Natural pozzolonas 2.Artificial pozzolonas. Natural pozzolonas
such as clay and shale, diato-maceous earth etc are processed
involving crush-ing, grinding and size preparation, including
ther-mal activation if necessary. The natural pozzolonas have lost
their popularity in view of the availability of more active
pozzolonas available as industrial by products.
Artificial pozzolonas such as fly ash, blast furnace slag, micro
silica, rice husk ash, metakaoline are major industrial by
products.
Advantages of Pozzolonas:
Generally concrete fails due to combined action of various
detrimental agencies. Durability of concrete depends on many
factors including volume change of concrete. Physical effects that
adversely influ-ence the durability of concrete include surface
wear, cracking due to crystallization, pressure of salts in pores
and exposure to extreme temperatures, del-eterious chemical effects
including leaching of the cement paste by acidic solutions and
expansive re-actions involving alkali-aggregate attack, sulphate
attack and corrosion of embedded steel in concrete. The aspect of
progressive hydration of cement is connected with the volume change
of gel and conse-quently in interior space. The unsoundness of
con-stituent materials such as cement, reactive aggre-gates
containing unsound mineral fractions causes volume changes and
hence affects durability.
Fly Ash:
Fly ash is divided into three classes depending on its calcium
content, in recognition of the difference in behavior between low
and high lime fly ashes. These classes are as follows:
Type F, low calcium, 8% CaOType CI, intermediate calcium, 820%
CaOType CH, high calcium, .20% CaO
Advantage of fly Ash in concrete:
The technical benefits of using fly ash in concrete are
numerous. The various advantages found by dif-ferent investigators
in India are summarized bellow 1. Superior pozzalonic action 2.
Reduced water demand (for fly ash low carbon content and high
fineness) 3. Improved workability 4. More effective action of water
reducing admix-tures5. Reduced segregation and bleeding 6.
increases setting time but remains within limits 7. Less heat of
hydration 8. Less drying shrinkage 9. Higher ultimate compressive
strength, tensile, flexural and bond strength 11. Higher ultimate
modulus of elasticity.12. Reduced alkali-aggregate reaction 13.
Improved freezing and thawing
Micro Silica:
During the last three decades, some new Pozzolan materials have
emerged in the building industry as an off shoot of research aimed
at energy conser-vation and strict enforcement of pollution control
measures to stop dispersing the materials into the atmosphere.
Micro Silica (other names have been used are silica dust, condensed
silica fume) is one such Pozzolan, which has been used as a partial
replacement of Portland cement due to its versatile properties. The
availability of high range water-re-ducing admixtures
(superplasticizers) has opened up new ideas for the use of Micro
Silica as part of the cementing material in concrete to produce
very high strength cement (> 100 Mpa/15,000 psi).
Ternary Blended System (Ternary cement sys-tem):
It means Micro Silica or other cement replacement additives are
to be used with OPC only. That is not strictly true and ternary
mixtures comprise efficient -systems. The primary incentive of
adding limited amount Micro Silica for example 5 percent with
Fly-ash cement mixes was to ensure high early strength research has
however, shown that Ternary mixtures of OPC, Micro Silica and
Fly-ash result in synergic action to improve the micro structure
and performance of concrete. When both Micro Silica and Fly-ash are
used, the resultant enhancement of strength or pozzolanic activity
was greater than super position of contributions of each, for the
re-spective proportions. Such synergic effect results from
strengthening the weak transition zone in ag-gregate cement
interface, as well as segmentation and blocking of pores.
Depending upon the service environment in which
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it is to operate, the concrete structure may have to encounter
different load and exposure regimes. In order to satisfy the
performance requirements, different ternary compounds required.
Such as ce-ment, fly-ash, silica fume. Greater varieties are
in-troduced by the corporation of additives like poz-zolana,
granulated slag are inert fillers this leads to different
specifications of cements in national or international.
Effects of Ternary cement system:
The combination of Micro Silica and Fly ash in a Ternary cement
system (i.e., portland cement being the third component) should
result in a number of synergistic effects, some of which are
obvious or in-tuitive, as follows: Micro Silica compensates for low
early strength of concrete with low CaO fly ash. Fly ash increases
long-term strength devel-opment of Micro Silica concrete. Fly ash
offsets increased water demand of silica fume. Micro Silica reduces
the normally high levels of high CaO fly ash required for sulphate
resist-ance and ASR prevention. Very high resistance to chloride
ion penetra-tion can be obtained with ternary blends. Fly ash due
to presence of spherical particles that easily rollovers one
another reducing inter par-tial friction (call bearing effects)
leads to improved workability and reduction in water demand.
Durability advantage:
Since industrial wastes are relatively lesser-known materials
than cement, it possible to have ques-tions on their long-term
effects on concrete. Doubts about effects of Fly ash and Micro
Silica on durabil-ity of concrete had initially inhibited their
full use in structural concrete. However, experience over the years
and continuous research has actually re-vealed positive effects on
durability. Corrosion of re-inforcement, sulphate attack, heat of
hydration and alkali silica reaction (ASR) in concrete are the
ma-jor issues of durability. Use of Fly ash, Micro Silica is known
to be beneficial in all such cases. These are supported by
well-documented case studies and performance records reported from
foreign sources. Data and case studies on Indian experiences with
indigenous materials have been presented earlier,
hence only the salient trends are enumerated.
Aim of the Present Study:
The environment in some concrete structures can become very
acidic due to formation of sulphuric acid converted from hydrogen
sulphide by bacterial action. Significant deteriation of concrete
in such harsh environments has been reported world wide.
Deteriotation of sewer system may result in serious problem such as
the loss of ability to transport sew-erage, contamaniation of
ground and ground water, excessive ground settelements.
Very high costs are involved with the repair of dete-riorated
concrete structures. In the USA, sulphuric acid is responsible for
billoins of dollars of damage to concrete waste water collection
and treatment systems. In the state of south Australia alone an
estimated budjet for maintaining the existing waste water infra
structure is A $ 48 million per anum. Although it has been reported
that some new mate-rials can be more acid resistant such as
concretes using melted sulphur as the binder or high propor-tions
of polymer modified binders, these materials are too expansive for
most practical applications. Therefore, the research into
improvement of acid re-sistance of normal concretes is still
attractive.
Over the past 20 years the use supplementary ce-mentitious
materials (SCM) in concrete has become very common due to their
technological, economical and environmental benefits. The use of
SCM such as Micro silica and fly ash in concretes has been found to
improve the resistance of concrete sulphu-ric acid attack because
of the reduced presence of calcium hydroxide, which is most
vunerable to acid attack. Using Micro silica in binary cement
system as partial replacement of ordinary portland cement was found
to be effective in reduciton of acid attack.
In the present investigation, 5% Micro Silica and 15 % Fly Ash
is added by the weight of the cement as additional ingredients in
concrete with different wa-ter/ binder ratios 0.55, 0.45 and 0.35
of Ordinary concrete and Ternary concrete mix . The behaviour of
this Ordinary concrete and Ternary concrete mix studied for
durablity properties like % Weight loss, % Loss of Compressive
strength and Durability Fac-tors by the immersion concrete
specimens in 5% H2SO4 and 5 % HCl solution for 28 days,90 days and
180 days.
EXPERMENTAL INVESTIGATION
Introduction:
The present investigations are aimed at to study durability of
Ternary Blended concrete, having 5% Silica fume and 15% Fly Ash by
weight of cement with different W/B ratios 0.55, 0.45and 0.35. In
the laboratory after the age of 28 Days, 90 Days and 180 Days.
MATERIALS
Cement
Locally available 53 grade of Ordinary Portland Ce-ment (Ultra
Tech Brand.) confirming to IS: 12269 was used in the
investigations. Table 4.1 gives the physical properties of OPC used
in the present in-vestigation and they conform to IS
specifications.
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International Journal of Research and Innovation (IJRI)
Photomicrograph of Portland cement (Curtsy Micro Silica
Manual)
Fly Ash:
The fly ash obtained from Hyderabad Industries, Andhra Pradesh
is used in the present experimental work.
Table 4.4.1 gives properties of flyash. The chemical composition
of flyash is rich in silica content which react with calcium
hydroxide to form C-S-H gel. This gel is responsible for the
strength mortar or concrete. The fly ash used to the specification
of grade 1 flyash
Photomicrograph of Fly ash (Curtsy Aci Jurnal)
Micro Silica:
The Micro Silica obtained from Oriental Trexim Pvt Ltd . Micro
Silica conforming to a standard approved by the deciding authority
may be used as part replacement of cement provided uniform blending
with the cement is ensured. The Micro Silica (very fine
non-crystalline silicon dioxide) is a by-product of the manufacture
of silicon, ferrosilicon or the like, from quartz and carbon in
electric arc furnace.
Table 4.5.1 gives properties of Micro Silica. The chemical
composition of Micro Silica is rich in silica.
Micrograph showing: Micro Silica (Curtsy by Micro Silica
Manual)
AGGREGATE:
The size, shape and gradation of the aggregate play an important
role in achieving a proper concrete. The flaky and elongated
particles will lead to blocking problems in confined zones. The
sizes of aggregates will depend upon the size of rebar spacing.
The coarse aggregate chosen for Ternary Blended Concrete is
typically angular in shape, is well graded, and smaller in maximum
size that suited for conventional concrete; typical conventional
concrete should have a maximum aggregate size of 20mm. Gradation is
an important factor in choosing a coarse aggregate, especially in
typical uses of Ternary Blended. Gap-graded coarse aggregate
promotes segregation to a greater degree than the well graded
coarse aggregate.
Fine Aggregates:
The locally available sand is used as fine aggregate in the
present investigation. The sand is free from clayey matter, salt
and organic impurities. The sand is tested for various properties
like specific gravity, bulk density etc., and in accordance with IS
2386-1963. The fine aggregate is conforming to standard
specifications.
Coarse Aggregates:
Machine crushed angular granite metal of 20mm nominal size from
the local source is used as coarse aggregate. It is free from
impurities such as dust, clay particles and organic matter etc. The
course aggregate is also tested for its various properties. The
specific gravity, bulk density and fineness modules of coarse
aggregate are found to be 2.70, 1560 kg/cum and 7.1
respectively.
Water:
Locally available water used for mixing and curing which is
potable, shall be clean and free from injurious amounts of oils,
acids, alkalis, salts, sugar, organic materials or other substances
that may be deleterious to concrete or steel.
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International Journal of Research and Innovation (IJRI)
Superplasticizer:
Superplasticizer CONPLAST 430 of Fosroc Chemical India Ltd. Was
used as water reducing admixture. It increases workability
Mix Proportion in the Laboratory:
The proportion used in preparation of mix is calculated as per
BIS Method.
The ratio between F.A and C.A is p: (1-p )
Illustrative Example for Mix Design Mix Design for W/C ratio =
0.55
i. Text data for materials Specific gravity of cement =2.95
Specific gravity of Coarse Aggregate =2.70 Specific gravity of Fine
Aggregate =2.53
ii. Selecting W/B ratio =0.55iii. Determination of cement
content Water =178 Ltrs. Cement =323.6 Kgs.
iv. Determination of F.A and C.A
Fine Aggregate0.98= [178+ (323.6/2.95)+
(1/0.42)*(F.A/2.53)]*1/100=736 Kgs.
Coarse Aggregate0.98= [178+ (323.6/2.95)+
(1/1-0.42)*(C.A/1-2.2.7)]*1/100= 1084 Kgs.
v. Mix Proportion = 1.00:2.27:3.34:0.55
Similarly Mix proportions for other W/B are obtained and are as
follows;For W/B ratio 0.55 Ternary Blended Concrete mix proportion
is 1.00:2.27:3.34:0.55 For W/C ratio 0.45 Ordinary Concrete mix
proportion is 1.00:1.78:2.73:0.45For W/B ratio 0.45 Ternary Blended
Concrete mix proportion is 1.00:1.78:2.73:0.45For W/C ratio 0.35
Ordinary Concrete mix proportion is 1.00:1.26:2.11:3.55
For W/B ratio 0.35 Ternary Blended Concrete mix proportion is
1.00:1.26:2.11:3.55
PREPARATION OF TEST SPECIMENS:
Mixing:
Mixing of ingredients is done in a rotating drum. Thorough
mixing by hand, using trowels is adopted.
The cementitious materials are thoroughly blended with hand and
then the aggregate is added and mixed followed by gradual addition
of water and mixing. Wet mixing is done until a mixture of uniform
color and consistency are achieved which is then ready for casting.
Before casting the specimens, workability of the mixes was found by
compaction factor test.
The concrete mix design using the data obtained from the test on
its ingredients. The mix proportions with different W/B ratios are
shown in the table 4.6.1, 4.6.2 and 4.6.3 of Ordinary concrete and
Ternary Blended Concrete. The adopted is BIS method.
Workability Test:
Immediately after mixing each of concrete, was tested for
workability by compaction factor apparatus in the laboratory. Table
4.7 gives the Compaction Factor value for different mixes, and the
Degree of Workability of mixes is medium for W/B 0.55, 0.45 and
0.35 of Ordinary and Ternary Blended Concrete
Compaction:
All the specimens were compacted by using pin vibrator.
Casting of Specimens:
The cast iron moulds are cleaned of dust particles and applied
with mineral oil on all sides before concrete is poured in the
moulds.
The moulds are of size 100mm x 100mm for cubes .The moulds are
placed on a level platform. The well mixed green concrete is filled
in to the moulds by vibration with needle vibrator. Excess concrete
was removed with trowel and top surface is finished level and
smooth.
Curing of the Specimens:
The specimens are left in the moulds undisturbed at room
temperature for about 24 hours after casting. The specimens are
then removed from the moulds and immediately transferred to the
curing pond containing clean and fresh water.
Testing of Specimens:
A time schedule for testing of specimens is maintained to ensure
their proper testing on the
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due date and time. The cast specimens are tested as per standard
procedures, immediately after they are removed from curing pond and
wiped off the surface water. The test results are tabulated
carefully
Description of Compression Testing Machine:
The compression testing machine (Microprocessor based) used for
testing the cube specimens is of standard make. The capacity of the
testing machine is 200 Tonnes or 2000 KN. The machine has an ideal
gauge on which the load applied can be read directly. The oil level
is checked, the MS plates are cleaned and the machine is kept ready
for testing specimens.
Testing Arrangements:
The specimens are removed from the curing pond just before
testing on the specified due date and time and cleaned to wipe off
the surface water. The cube specimen is placed on the lower platen
such that the load is applied centrally on the faces other than top
and bottom faces of casting.
TESTS CONDUCTED:
Compressive strength of Concrete Specimens:
The compressive strength of control concrete (ordinary concrete)
and Ternary Blended concrete contain 5% Micro Silica and 15% Fly
ash concrete specimens having W/B 0.55, W/B 0.45 and W/B 0.35 were
tested.
Durability Studies of Ordinary and Ternary Blended Concrete:
In addition to strength durability property is also important
for concrete, when concrete is exposed to aggressive environment
consisting of chlorides and sulphates it should not be subjected to
deterioration. Pozzolanic admixtures are replacements for cement in
concrete are known to enhance the durability property of the
concrete. To study the effect of Fly ash and Micro Silica
replacement on durability, acid resistance test have been conducted
in the laboratory.
DURABILITY OF CONCRETE:
The durability of Control concrete and Ternary blended concrete
was tested for resistance against mineral and organic acids such as
Sulphuric acid, hydrochloric acid and chlorides etc. The effect of
chemical attack on plain (ordinary concrete) concrete and Ternary
concretes was studied by physical observation and loss in
weight.
Acid pond test:
Acid solution for immersion test. The method was modified for
testing concrete in this investigation. A H2SO4 (Sulphuric) acid
and HCl (Hydro chloride
Acid) of 5% concentration was chosen for this accelerated
laboratory investigation to simulate the aggressive environment of
some sewer structures. All the concrete cubes of 100mmx100mm size
were continuously immersed in weekly refreshed 5% H2SO4 and HCl
acid during the test period.
Visual inspection of concrete samples:
During the immersion period in 5% H2SO4 (Sulphuric) acid and HCl
(Hydro chloride Acid) solution, the concrete cube samples were
periodically retrieved from the acid solution for visual inspection
of the surface appearance. Photographs were also taken of cubes
samples after immersion in the acid over different time periods to
record changes in surface appearance.
Mass changes of cubes over immersion time:
The mass change of the cubes of each concrete with the immersion
time in 5% H2SO4 (Sulphuric) acid and HCl (Hydro Chloride Acid)
solution.
EXPERIMENTAL RESULTS
Cement:
Physical Properties of Ordinary Portland Cement
S.No. Property Test Results1 Normal Consistency 32%2 Initial
Setting time 90 min3 Final Setting time 250 min4 Specific Gravity
of Ce-
ment2.95
5 Compressive Strength (at 28 days)
56.3 N/mm2
Fine Aggregate:
Physical Properties:
S.No Property Test Results1 Fineness
modulus2.48
2 Specific gravity 2.533 Bulk density
a).Looseb). Com-pacted
1600 kg/m3
1720 kg/m3
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International Journal of Research and Innovation (IJRI)
Sieve analysis: Sample 1000 gms
S.No. I.S Sieve Size
Wt. Retained (gms.)
Cumu-lative Wt. Re-tained (gms.)
Cumula-tive % of wt Retained
% Pass-ing
1 4.75 mm
0.61 0.61 0.061 99.939
2 2.36 mm
2.6 3.21 0.321 99.679
3 1.18 mm
40 43.21 4.32 95.68
4 600 463 506.21 50.62 49.38
5 300 432 938.21 93.82 6.18
6 150 59.8 998.01 99.8 0.2
7
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International Journal of Research and Innovation (IJRI)
GRAPHS
Percentage of weight loss vs. Age in Days for W/B 0.55 Immersed
in 5%H2SO4 Solution at 28 days, 90 days and 180 days.
Percentage of weight loss vs. Age in Days for W/B 0.45 Immersed
in 5%H2SO4 Solution at 28 days, 90 days and 180 days.
Percentage of weight loss vs. Age in Days for W/B 0.35 Immersed
in 5%H2SO4 Solution at 28 days, 90 days and 180 days.
Percentage of weight loss vs. Age in Days for W/B 0.55 Immersed
in 5%HCl Solution at 28 days, 90 days and 180 days.
Percentage of weight loss vs. Age in Days for W/B 0.45 Immersed
in 5%HCl Solution at 28 days, 90 days and 180 days.
Percent age of weight loss vs. Age in Days for W/B 0.35 Immersed
in 5%HCl Solution at 28 days, 90 days and 180 days.
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International Journal of Research and Innovation (IJRI)
Combined Graph Percentage of weight loss vs. Age in Days for W/B
0.55, 0.45 and 0.35 Immersed in 5% H2SO4 Solution at 28 days, 90
days and 180 days.
Combined Graph Percentage of weight loss vs. Age in Days for W/B
0.55, 0.45 and 0.35 Immersed in 5%HCl Solution at 28 days, 90 days
and 180 days.
Percentage Loss of Compressive strength of after immersed in 5%
H2SO4 Solution at 28 days, 90 days and 180 days.
Percentage Loss of Compressive strength of after immersed in 5%
HCl Solution at 28 days, 90 days and 180 days.
DISCUSSION OF TEST RESULTS
Durability Studies on Ternary Blended Concrete
In addition to the strength, durability properties are also
important for concrete. When concrete is exposed to aggressive
environment consisting of sulphate, acids, chlorides. It should not
be subjected to deterioration. Pozzolonic admixtures as replacement
for cement in concrete are known to enhance the durability property
of concrete. To study the test of Ternary Blended Concrete on
durability acid resistance test and Rapid Chloride Permeability
Test have been conducted in the laboratory.
Concrete specimens of size 100X100X100 mm are cured for 28 days
and are immersed in 5% HCL , 5% H2SO4 for the period of 28 days ,
90 days and 180 days of different water binder ratios of 0.55 ,
0.45, and 0.35. All types of experiments are conducted for
comparison of Ordinary Concrete and Ternary Blended Concrete in
respect of acid resistance.
Studies on Loss of weight of Ordinary concrete and Ternary
Blended concrete in different solutions
Loss of weight of specimens after immersing in 5% H2SO4
solution
Table 4.8.1 gives the percentage weight loss of W/C ratios 0.55,
0.45 and 0.35 of ordinary concrete after immersing in 5% H2 SO4
solution ranges from 4.87% to 2.12% for 28 days, 13.17% to 8.95%
for 90 days, 17.16 % to 11.29% for 180 days respectively.
Table 4.8.2 gives the percentage weight loss of W/B ratios 0.55,
0.45 and 0.35 of Ternary Blended Concrete after immersing in 5% H2
SO4 solution ranges from 3.43 to 1.84% for 28 days, 11.71 to
6.50for 90 days, 15.21% to 9.54% for 180 days respectively.
The percentage weight loss of W/B ratio 0.55, 0.45 and 0.35 of
ordinary concrete and Ternary Blended Concrete after immersing in
5% H2 SO4 solution increases corresponding to the time.
Loss of Weight of specimens after immersing in 5% HCl solution
Table 4.9.1 gives the percentage weight loss of W/C ratios 0.55,
0.45 and 0.35 of ordinary concrete after immersing in 5% HCl
solution ranges from 3.52% to 1.33% for 28 days, 9.46% to 5.13% for
90 days, and 12.41% to 7.8 for 180 days respectively.
Table 4.9.2 gives the percentage weight loss of W/B ratios 0.55,
0.45 and 0.35 of Ternary Blended Concrete after immersing in 5% HCl
solution ranges from 2.87% to 1.10% for 28 days, 7.38% to 2.79% for
90 days, 10.21% to 4.64% for 180 days respectively.
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International Journal of Research and Innovation (IJRI)
The percentage weight loss of W/B ratio 0.55, 0.45 and 0.35 of
ordinary concrete and ternary concrete after immersing in 5% Hcl
solution increases corresponding to the time.
Studies on Loss of Compressive strength of Ordinary and Ternary
Blended Concrete Loss of Compressive strength of specimens after
immersing in 5% H2 SO4 solution
Table 4.11.1 gives the percentage Loss of Compressive strength
of W/C ratios 0.55, 0.45 and 0.35 of ordinary concrete after
immersing in 5% H2 SO4 solution ranges from 34.20% to 24.11% for 28
days, 54.63% to 43.20% for 90 days, and 68.83 % to 56.92% for 180
days respectively.
Table 4.11.1 gives the percentage Loss of compressive strength
of W/B ratios 0.55, 0.45 and 0.35 of Ternary Blended Concrete after
immersing in 5% H2 SO4 solution ranges from 31.99% to 22.20% for 28
days, 5.63% to 40.55% for 90 days, 66.92% to 58.33% for 180 days
respectively.
The Loss of compressive strength of W/B ratio 0.55, 0.45 and
0.35 of ordinary concrete and Ternary Blended Concrete after
immersing in 5% H2 SO4 solution increases corresponding to the
time.
Under Sulfuric acid attack, calcium sulphate formed, can
continue to react with calcium aluminate phase in cement to form
Calcium Sulphoaluminate, which on crystallization can cause
expansion and disruption of conctete.
Loss of Compressive strength of specimens after immersing in 5%
HCl solution
Table 4.11.2 gives the percentage Loss of Compressive strength
of W/C ratios 0.55, 0.45 and 0.35 of ordinary concrete after
immersing in 5% HCl solution ranges from 9.37% to 5.34% for 28
days, 19.60% to 10.50% for 90 days, 25.11% to 16.23% for 180 days
respectively.
Table 4.11.2 gives the percentage Loss of Compressive strength
of W/B ratios 0.55, 0.45 and 0.35 of Ternary Blended Concrete after
immersing in 5% HCl solution ranges from 8.37% to 4.51% for 28
days, 14.01% to 8.55% for 90 days, 22.61% to 15.16% for 180 days
respectively.
The percentage Loss of Compressive strength of W/B ratio 0.55,
0.45 and 0.35 of ordinary concrete and Ternary Blended Concrete
after immersing in 5% HCl solution increases corresponding to the
time.
Studies on Durability Factors of Ordinary and Ternary Blended
concrete
Durability Factors of Ordinary and Ternary Blended concrete
specimens after immersing in
5% H2 SO4 solution
Table 4.12 gives Durability Factors of W/C ratios 0.55, 0.45 and
0.35 of ordinary concrete after immersing in 5% H2 SO4 solution.
These values are observed to be ranges from 10.23 to 11.80 for 28
days, 22.68 to 28.4 for 90 days, and 31.70 to 43.92 for 180 days
respectively.
Table 4.12 gives the percentage Loss of Compressive strength of
W/B ratios 0.55, 0.45 and 0.35 of Ternary Blended Concrete after
immersing in 5% H2 SO4 solution. These values are observed to be
ranges from 10.57 to 12.10 for 28 days, 23.92 to 29.72 for 90 days,
33.08 to 46.67 for 180 days respectively.
Durability Factors of Ordinary and Ternary Blended concrete
specimens after immersing in 5% HCl solution
Table 4.12 gives Durability Factors of W/C ratios 0.55, 0.45 and
0.35 of ordinary concrete after immersing in 5% HCl solution. These
values are observed to be ranges from 14.03 to 14.72 for 28 days,
40.20 to 44.75 for 90 days, and 74.89 to 83.77 for 180 days
respectively.
Table 4.12 gives the percentage Loss of Compressive strength of
various W/B ratios 0.55, 0.45 and 0.35 of Ternary Blended Concrete
after immersing in 5% HCl solution. These values are observed to be
ranges from 14.25 to 14.85 for 28 days, 42.99 to 45.72 for 90 days,
77.39 to 84.84 for 180 days respectively.
CONCLUSIONS:
The Following Conclusions are drawn from the Experimental
Investigation in present Thesis:
1. From the visual observation of test specimens immersed in 5%
H2SO4 solution for 28 days, 90 days and 180 days, the specimens has
undergone deterioration. Which are viewed in photograph
enclosed.
2. The investigation shows that percentage of weight loss of
specimens increased as days of immersion in 5% H2SO4 is increased
for Ordinary concrete and Ternary concrete for all W/C ratios. In
case of Ordinary concrete for 0.55 Water/ Cement ratio the
percentage of weight loss is 4.87 at 28 days immersion and it is
17.16 for 180 days immersion. In case of Ternary Blended concrete
for 0.55 Water/ Binder ratio the percentage of weight loss is 3.43
at 28 days immersion and it is 15.21 for 180 days immersion.
3. From the visual observation of test specimens immersed in 5%
HCl solution for 28 days, 90 days and 180 days, the specimens has
undergone deterioration.
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International Journal of Research and Innovation (IJRI)
4. The investigation shows that percentage of weight loss of
specimens increased as days of immersion in 5% HCl is increased for
Ordinary concrete and Ternary Blended concrete for all W/B ratios.
In case of Ordinary concrete for 0.55 Water/ Cement ratio the
percentage of weight loss is 3.52 at 28 days immersion and it is
12.41 for 180 days immersion. In case of Ternary concrete for 0.55
Water/ Binder ratio the percentage of weight loss is 2.82 at 28
days immersion and it is 10.21 for 180 days immersion.
5. The percentage weight loss of Ordinary concrete and Ternary
Blended concrete after immersing in 5 % H2SO4 solution increases
corresponding to the time.
6. The percentage weight loss of Ordinary concrete and Ternary
Blended concrete after immersing in 5 % HCl solution increases
corresponding to the time.
7. The percentage loss compressive strength of Ordinary concrete
and Ternary Blended concrete after immersing in 5 % H2SO4 solution
and 5% HCl solution increases corresponding to the time.
8. The Durability Factors of Ternary Blended concrete mixes are
more than those of Ordinary concrete mixes.
9. Higher the Durability Factor higher will be the resistance to
the Acids and Sulphates attacks.
10. A reduction in pores in concrete improves the surface
integrity of concrete, improves its homogeneity good bonding and
reduces the probability of cracks.
PHOTOGRAPHS:
Ordinary Concrete Specimen of W/C Ratio 0.55 after Immersion in
5% H2SO4 Solution at 28 days
Ternary Blended concrete Specimen of W/B Ratio 0.55 after
Immersion in 5% H2SO4 Solution at 28 days
Ordinary Concrete Specimen of W/C Ratio 0.55 after Immersion in
5% H2SO4 Solution at 90 days.
Ternary Blended Concrete Specimen of W/B Ratio 0.55 after
Immersion in 5% H2SO4 Solution at 90 days
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International Journal of Research and Innovation (IJRI)
Ordinary Concrete Specimen of W/C Ratio 0.55 after Immersion in
5% H2SO4 Solution at 180 days
Ternary Blended Concrete Specimen of W/B Ratio 0.55 after
Immersion in 5% H2SO4 Solution at 180 days
Ordinary Concrete Specimen of W/C Ratio 0.45after Immersion in
5% H2SO4 Solution at 28 days
Ternary Blended Concrete Specimen of W/B Ratio 0.45 after
Immersion in 5% H2SO4 Solution at 28 days
Ordinary Concrete Specimen of W/C Ratio 0.45after Immersion in
5% H2SO4 Solution at 90 days
Ternary Blended Concrete Specimen of W/B Ratio 0.45 after
Immersion in 5% H2SO4 Solution at 90 days
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International Journal of Research and Innovation (IJRI)
Ordinary Concrete Specimen of W/C Ratio 0.45 after Immersion in
5% H2SO4 Solution at 180 days
Ternary Blended Concrete Specimen of W/B Ratio 0.45 after
Immersion in 5% H2SO4 Solution at 180 days
Ordinary Concrete Specimen W/C Ratio 0.35 after Immersion in 5%
H2SO4 Solution at 28 days
Ternary Blended Concrete Specimen of W/B Ratio 0.35 after
Immersion in 5% H2SO4 Solution at 28 days
Ordinary Concrete Specimen of W/C Ratio 0.35 after Immersion in
5% H2SO4 Solution at 90 days
Ternary Blended Concrete Specimen of W/B Ratio 0.35 after
Immersion in 5% H2SO4 Solution at 90 days
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International Journal of Research and Innovation (IJRI)
Ordinary Concrete Specimen of W/C Ratio 0.35 after Immersion in
5% H2SO4 Solution at 180 days
Ternary Blended Concrete Specimen of W/B Ratio 0.35 after
Immersion in 5% H2SO4 Solution at 180 days
Ordinary Concrete Specimen of W/C Ratio 0.55 after Immersion in
5% HCl Solution
Ternary Blended Concrete Specimen of W/B Ratio 0.55 after
Immersion in 5% HCl Solution
Ordinary Concrete Specimen of W/C Ratio 0.45 after Immersion in
5% HCl Solution
Ternary Blended Concrete Specimen of W/B Ratio 0.45 after
Immersion in 5% HCl Solution
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International Journal of Research and Innovation (IJRI)
Ordinary Concrete Specimen of W/C Ratio 0.35 after Immersion in
5% HCl Solution
Ternary Blended Concrete Specimen of W/B Ratio 0.35 after
Immersion in 5% HCl Solution
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Author
Ramanujapuram.NandiniAurora's Scientific Technological &
Research Academy,Hyderabad,India
K. Mythili,AssociateProfessor,Department of Civil Engineering,
Aurora's Scientific Technological & Research Acad-emy,
Hyderabad, India
Abstract