High strength m70 concrete grade

HIGH STRENTH M70 GRADE CONCRETE Page i
HIGH STRENGHT M70 GRADE
CONCRETE

HIGH STRENTH M70 GRADE CONCRETE Page 2
R.H. PATEL INSTITUTE OF TECHNOLOGY
GOBLEJ, KHEDA
CERTIFICATE
This is to certify that
JAY PANCHAL
Have completed Project work of title “HIGH STREGTH M70 GRADE
CONCRETE” They have undergone the process of literature survey
and project work. They are supposed to carry out the residue of work
on same project during semester-6 for the final fulfillment of the
work which is prerequisite to complete diploma engineering.
Signature of Guide Signature of Head of Department

ACKNOWLEGEMENT
We are thankful to GUJRAT TECHNOLOGICAL UNIVERSITY (GTU) for
including project in our curriculum. We are also thankful to R.H
PATEL INSTITUTE OF TECHNOLOGY to provide us all the facilities to
carry out the project smoothly.
We would like to pay our sincere gratitude towards our guide, MS.
MAITRY PATEL, for providing her valuable guidance and motivating
the team throughout the project work. Our hearty thanks to the
principal and Head of the Civil Engineering Department, RHPIT for
their encouragement for the project.

ABSTRACT
This paper covered major aspectof m70 grade concrete mix design as the
quality control measureof concrete production, using American method of
concrete mix design procedure. Itis aimed at highlighting the importantof
designed concrete as compared to an ordinary ratio analyzed concrete in
concrete production for any civil/structuralconcrete work. This is to analyze
the merit and demerit of designed and controlof concrete production as
required by BS 8110 in structuralrequirement. Itequally include the whole
laboratory test analysis, to determine the physicaland geotechnical properties
of the materials needed for the mix design in order to attain the required data
for the design procedure, in accordanceto the parent material types and
location, and the specific density of the designed concrete, that will be
suitable, adoptable, durable, economical, workableand generally safe for the
structuraldesign objective of the weather condition in any specified locality.
This is equally aimed at controlling the rate of structuralfailure in Nigeria as
nations in this regard all factors that may lead to failure of concrete structure
were generally treated. The design covered concrete grade 25N/mm2;
30N/mm2 and these weredesigned to attain the required strength grade after
28 days of curing specially with water as the minimum strength. Basically the
designs weredone with Burnham cement as one of the Brand of ordinary
Portland cement. Itwas equally considered as a factor that all the gradeof
concrete designed for, should achieve 65% strength after been cured for seven
days in water. The individual resultof the design mix were adequately
presented and have shown that generally mix design of concrete before
production as measureof quality controlof concrete work is very important in
any civil. Projecteither for Governmentand individual. Quality control should
be applicable, to control structuralfailure.

INDEX
NAME PAGE NO.
Introduction 8-13
 Requirements of concretemix design
 Basic considerations
 Gradeof concrete
High strength M70 grade concrete 13-16
 Properties of High performanceConcrete
 High modulus of elasticity
 High abrasion resistance
 High durability and long life in severe environments
 Low permeability and diffusion
 Resistance to chemical attack
 High resistanceto frostand deicer scaling damage
 Toughness and impact resistance
 Ease of Placement
 Chemical Attack
High-performanceConcreteParameters 17-17
Material Selection 18-27
 Cement
 Aggregate
 admixtures
Objective 28-28
Mix Design of M70 29-35

Test Results 36-37
Graphs 38-39
Conclusion 39-39

INTRODUCTION
For the design requirement of any concrete structured projectto be achieved,
close supervision of the projectand adequate concrete mix design should be
by the civil Engineer involved. In recent year we have witness allot of concrete
structuralfailure either during construction, after the completion or few year
of the project age of completion, without satisfying design age of the project
life.
The compressivestrength of hardened concrete which is generally considered
to be an index of its other properties, depends upon many factors, e.g. quality
and quantity of cement, water and aggregates; batching and mixing; placing,
compaction and curing. The cost of concrete is made up of the costof
materials, plant and labour. The variations in the cost of materials arise from
the fact that the cement is severaltimes costly than the aggregate, thus the
aim is to produceas lean a mix as possible. From technical point of view the
rich mixes may lead to high shrinkageand cracking in the structuralconcrete,
and to evolution of high heat of hydration in mass concrete which may cause
cracking.
The actual costof concrete is related to the cost of materials required for
producing a minimum mean strength called characteristic strength that is
specified by the designer of the structure. This depends on the quality control
measures, butthere is no doubt that the quality control adds to the cost of
concrete. The extent of quality control is often an economic compromise, and
depends on the sizeand type of job. The cost of labour depends on the
workability of mix, e.g., a concrete mix of inadequate workability may result in
a high cost of labour to obtain a degree of compaction with available
equipment.

Requirements of concrete mix design
The requirements which formthe basis of selection and proportioning of mix
ingredients are:
a) The minimum compressivestrength required from structuralconsideration
b) The adequate workability necessary for fullcompaction with the compacting
equipment available.
c) Maximum water-cement ratio and/or maximum cement content to give
adequate durability for the particular site conditions
d) Maximum cement content to avoid shrinkagecracking dueto temperature
cycle in mass concrete.

Basic Considerations
Specifications
• The following point may be kept in mind while designing concrete mixes
• Minimum CompressiveStrength required
• Minimum water/ cement ratio
• Maximum cement content to avoid shrinkagecracks
• Maximum aggregate / cement ratio Maximum density of concrete in
case of gravity dams
Workability
• The following points related to workability shall be kept in mind while
designing concrete mixes.
• The consistency of concrete should no morethan that necessary for
placing, compacting and finishing.
• For concrete mixes required high consistency at the time of placing, the
use of water-reducing and set-retarding admixtures should be used
rather than the addition of more water
• Wherever possible, the cohesiveness and finishibility of concrete should
be improved by increasing sand/aggregate ratio than by increasing the
proportion of the fine particles in the sand.

Strength and durability
• Strength and durability require lower w/c ratio. Itis usually achieved not
by increasing the cement content, but by lowering the water at given
cement content. Water demand can by lowered by throughoutcontrol
of the aggregate grading and by using water reducing admixtures.

Grade of Concrete
• The concrete shall be in grades designated
Group Grade
designation
Characteristics
compressive strength of
150 mm cube at 28 days,
N/mm2
Ordinary Concrete M10
M15
M20
10
15
20
Standard Concrete M25
M30
M35
M40
M45
M50
M55
25
30
35
40
45
50
55
High Strength
Concrete
M60
M65
M70
M75
M80
60
65
70
75
80

High strength (M70) Grade Concrete
Concrete is defined as “high-strength concrete” solely on the basis of its
compressivestrength measured at given age.
Highperformance concrete (HPC) for concretemixtures possessing high
workability, high durability and high ultimate strength. Concrete, whose
ingredients, proportions and production methods are specifically chosen to
meet special performanceand uniformity requirements that cannot be always
achieved routinely by using only conventional materials, like, cement,
aggregates, water and chemical admixtures, and adopting normal mixing,
placing and curing practices. These performancerequirements can be high
strength, high early strength, high workability, low permeability and high
durability for severeservice environments, etc. or combinations thereof.
Production and useof such concrete in the field necessitates high degree of
uniformity between batches and very stringentquality control.
High performanceconcrete (HPC) is a specialized series of concrete
designed to provide severalbenefits in the construction of concrete
structures that cannotalways be achieved routinely using conventional
ingredients, normal mixing and curing practices. In the other words a high
performanceconcrete is a concrete in which certain characteristics are
developed for a particular application and environment, so that it will give
excellent performancein the structurein which it will be placed, in the
environmentto which it will be exposed, and with the loads to which it will be
subjected during its design life. Itincludes concrete that provides either
substantially improved resistanceto environmentalinfluences (durability in
service) or substantially increased structuralcapacity
while maintaining adequate durability. It may also include concrete, which
significantly reduces construction time without compromising long-term

serviceability. While high strength concrete, aims at enhancing strength and
consequentadvantages owing to improved strength, the term high-
performanceconcrete (HPC) is used to refer to concrete of required
performancefor the majority of construction applications without
compromising long-termserviceability. While high strength concrete, aims at
enhancing strength and consequentadvantages owing to improved strength,
the term high-performanceconcrete(HPC) is used to refer to concrete of
required performancefor the majority of construction applications.
Properties of High performance Concrete
• High modulus of elasticity
• High abrasion resistance
• High durability and long life in severe environments
• Low permeability and diffusion
• Resistance to chemical attack
• High resistanceto frostand deicer scaling damage
• Toughness and impact resistance
• Ease of placement
• Chemical Attack
• Carbonation
High Modulus of elasticity
The modulus of elasticity is a very importantmechanical property of concrete.
The higher the value of the modulus, the stiffer the material is. Thus,
comparing a high performanceconcrete to a normal strength concrete, it is
seen that the elastic modulus for high performanceconcretewill be higher,
thereby making it a stiffer type of concrete. Stiffness is a desirable property for
concrete to have because the deflection a structuremay experience will be

decreased. However, deformations, such as creep, increase in high strength
concrete
High abrasion resistance
Abrasion resistanceis directly related to the strength of concrete. This makes
high strength HPC ideal for abrasiveenvironments. Theabrasion resistanceof
HPC incorporating silica fumeis especially high. This makes silica fume
concrete particularly useful for spillways and stilling basins, and concrete
pavements or concrete pavement overlays subjected to heavy or abrasive
traffic.
High durability and long life in severe environments.
Durability problems of ordinary concrete can be associated with the severity of
the environmentand the use of inappropriatehigh water/binder ratios. High-
performanceconcrete that have a water/binder ratio between 0.30 and 0.40
are usually more durable than ordinary concrete not only becausethey are less
porous, butalso becausetheir capillary and pore networks aresomewhat
disconnected due to the development of self-desiccation. In high-performance
concrete (HPC), the penetration of aggressiveagents is quite difficult and only
superficial
Low permeability and diffusion
The durability and servicelife of concrete exposed to weather is related to the
permeability of the cover concrete protecting the reinforcement. HPC typically
has very low permeability to air, water, and chloride ions. Low permeability is
often specified through the useof a coulomb value, such as a maximum of
1000 coulombs. Thedense pore structureof high-performanceconcrete,
which makes it so impermeable, gives it characteristics that make it eminently
suitable for uses where a high quality concrete would not normally be
considered
Resistance to chemical attack
For resistanceto chemical attack on most structures, HPC offers a much
improved performance. Resistanceto various sulfates is achieved primarily by
the useof a dense, strong concreteof very low permeability and low water-to-

cementing materials ratio; these are all characteristics of HPC. Similarly
resistanceto acid fromwastes is also much improved.
High resistance to frost and deicer scaling damage
Because of its very low water-cementing materials ratio (less than 0.30), it is
widely believed that HPC should be highly resistant to both scaling and physical
breakup due to freezing and thawing. There is ample evidence that properly
air-entrained high performanceconcretes are highly resistant to freezing and
thawing and to scaling
Toughness and impact resistance
Both normal-strength concrete and high-strength concrete are brittle, with the
degree of brittleness increasing with increasing strength. The dynamic
mechanical performanceof high-strength concrete (HSC) under impact or
fatigue loading has received increasing attention in recent years because of the
rapid adoption of higher strength concrete in bridges, pavements, and marine
structures, and severalresearchers havestudied the impact or fatigue
performanceof concrete.
Many experimental results have indicated that the characteristics and
microstructureof both the interfacial zone and the bulk HSC are improved by
incorporating silica fume. As well, the addition of steel fibers can effectively
restrain the initiation and propagation of crack under stress, and improvethe
toughness.
Ease of Placement
High performanceconcrete can also be highly workableself-compacting
concrete which is type of HPC which can be easily placed even dense
reinforcement wherevibrators can’tbe used.
Chemical Attack
For resistanceto chemical attack on most structures, HPC offers a much
improved performance. Resistanceto various sulfates is achieved primarily by
the useof a dense, strong concreteof very low permeability and low water-to-
cementing materials ratio; these are all characteristics of HPC. Similarly
resistanceto acid fromwastes is also much improved

High-performance Concrete Parameters
Permeation is a major factor that causes prematuredeterioration of concrete
structures.
The provision of high-performanceconcretemustcenter on minimizing
permeation through proportioning methods and suitable construction
procedures (curing) to ensure that the exposureconditions do not cause
ingress of moisture and other agents responsiblefor deterioration.
Itis important to identify the dominant transportphenomenon and design the
mix proportion with the aim of reducing that transportmechanism which is
dominant to a predefined acceptable performancelimit based on permeability.
The parameter to be controlled for achieving the required performancecriteria
could be any of the following.
(1) Water/ (cement + mineral admixture) ratio
(2) Strength
(3) Densification of cement paste
(4) Elimination of bleeding
(5) Homogeneity of the mix
(6) Particle size distribution
(7) Dispersion of cement in the fresh mix
(8) Stronger transition zone

(9) Low free lime content
(10) Very little free water in hardened concrete
Material Selection
The main ingredients of HPC arealmost the same as that of conventional
concrete.
These are
1) Cement
2) Fine aggregate
3) Coarseaggregate
4) Water
5) Mineral admixtures (fine filler and/or pozzolanic supplementary
cementation materials)
6) Chemical admixtures (plasticizers, superplastisizers, retarders, air-
entraining agents)
Cement
There are two important requirements for any cement: (a) strength
development with time and (b) facilitating appropriate rheological
characteristics when fresh.

1) High C3A content in cement generally leads to a rapid loss of flow in
fresh concrete. Therefore, high C3A content should be avoided in
cements used for HPC.
2) The total amountof soluble sulphatepresent in cement is a fundamental
consideration for the suitability of cement for HPC.
3) The fineness of cement is the critical parameter. Increasing fineness
increases early strength development, but may lead to rheological
deficiency.
4) The super plasticizer used in HPC should havelong molecular chain in
which the sulphonategroup occupies the beta position in the poly
condensateof formaldehydeand melamine sulphonate or that of
naphthalene sulphonate.
5) The compatibility of cement with retarders, if used, is an important
requirement.
Aggregates

Coarse aggregates
The important parameters of coarseaggregate that influence the performance
of concrete are its shape, texture and the maximum size. Since the aggregate is
generally stronger than the paste, its strength is not a major factor for normal
strength concrete, or for HES and VES concretes. However, the aggregate
strength becomes important in the caseof high performanceconcrete. Surface
texture and mineralogy affect the bond between the aggregates and the paste
as well as the stress level at which micro cracking begins. The surfacetexture,
therefore, may also affect the modulus of elasticity, the shapeof the stress-
strain curve and to a lesser degree, the compressivestrength of concrete.
Since bond strength increases at a slower rate than compressivestrength,
these effects will be morepronounced in HES and VES concretes. Tensile
strengths may be very sensitive to differences in aggregatesurfacetexture and
surfacearea per unit volume.
Fine aggregate
Fine aggregates (FA) with a rounded particle shapeand smooth texture have
been found to require less mixing water in concrete and for this reason are
preferable in HSC. HSC typically contain such high contents of fine

cementations materials that the grading of the FA used is relatively
unimportant. However, it is sometimes helpful to increase the fineness
modulus (FM) as the lower FMof FA can give the concrete a sticky consistency
(i.e. making concrete difficult to compact) and less workablefresh concrete
with a greater water demand. Therefore, sand with a FM of about 3.0 is usually
preferred for HSC (ACI 363R, 1992).
Compressive strength of coarse aggregate
To make high-strength concrete we mustobviously usecoarseaggregate that
has a high compressivestrength to prevent rupturefrom occurring in the
coarseaggregate. We musttherefore find coarseaggregates that come from
quarries that producerocks with compressivestrengths above16,500 psi7 and
absolutely avoid rocks that are too softor which present cleavage planes. So
before making laboratory trial batches, we should determine the compressive
strengths of all the coarseaggregates economically available. Yet, as already
noted, it is not necessarily the strongestcoarseaggregatewhich will produce
the strongestconcrete, since the bond of the hydrated cement to that same
aggregate mustbe taken into account.
Shape of coarse aggregate
Because the bond between the coarseaggregate and the hydrated cement is
more of a mechanical type at the beginning, to make high-strength concrete
we ought to use a cubically shaped crushed stonerather than a natural gravel
or a crushed gravel. The type of crusher used by the aggregate producer is
important in this respect. Furthermore, the surfaces of the coarseaggregate
must be clean and free of any dust which would impair mechanical bonding. In
certain cases, washing of the aggregate may provenecessary. Careful
examination of aggregate samples from local quarries is sufficientto choose
the coarseaggregatethat offers the most usefulcharacteristics from this point
of view.
Maximum size of coarse aggregate
We could show that for a given aggregate there is a relation between its
maximum diameter and the maximum compressivestrength possiblefrom
concrete made with it. The absolute maximum strength seems to be obtained
with aggregates having a maximum sizeof 3⁄8 or 1⁄2 inch.8 Standard coarse

aggregates of Number 4 to- 3⁄8-inch 9 or Number 4-to-5⁄8-inch10 sizes arethe
most suitable.
Effect of Aggregate Type
The intrinsic strength of coarseaggregate is not an important factor if water-
cement ratio falls within the range of 0.50 to 0.70, primarily dueto the fact
that the cement-aggregate bond or the hydrated cement pastefails long
before aggregates do. It is, however, not true for very high strength concretes
with very low water-cementratio of 0.20 to 0.30. For such concretes,
aggregates can assumethe weaker-link role and fail in the form of trans
granular fractures on the failure surface. However, theaggregate minerals
must be strong, unaltered, and fine grained in order to be suitable for very
high strength concrete. Intra- and inter-granular fissures partially decomposed
coarse-grained minerals, and the presenceof cleavages and lamination planes
tend to weaken the aggregate, and therefore the ultimate strength of the
concrete.
The compressivestrength and elastic modulus of concrete are significantly
influenced by the mineralogical characteristics of the aggregates. Crushed
aggregates fromfine-grained debris and limestone give the best results.
Concretes made fromsmooth river gravel and from crushed granite containing
inclusions of a softmineral are relatively weaker in strength. There exists a
good correlation between the compressivestrength of coarseaggregate and
its soundness expressed in terms of weight loss. There exists a close
correlation between the mean compressivestrengths of the aggregate and the
compressivestrength of the concrete, ranging from 35 to 75 MPa, at both 7
days and 28 days of age.

Effect of Aggregate Size
The use of larger maximum nominal sizeof aggregate affects the strength in
severalways. First, sincelarger aggregates haveless specific surfacearea and
the aggregate-pastebond strength is less, the compressivestrength of
concrete is reduced. Secondly, for a given volume of concrete, using larger
aggregate results in a smaller volume of pastethereby providing more restraint
to volume changes of the paste. This may induce additional stresses in the
paste, resulting in micro cracks prior to application of load, which may be a
critical factor in very high strength (VHS) concretes. Therefore, it is the general
consensus thatsmaller sizeaggregate should be used to produce high
performanceconcrete.
Itis generally suggested that 10 to 12 mm is the appropriate maximum sizeof
aggregates for making high strength concrete. However, adequate
performanceand economy can also be achieved with 20 to 25 mm maximum
sizegraded aggregates by proper proportioning with a mid-range or high-range
water reducer, high volumeblended cements, and coarseground Portland
cement. Change in emphasis from water-cementations material ratio versus
strength relation to water-content versus durability relation will providethe
incentive for much closer control of aggregate grading than in the current
practices. A substantialreduction in water requirement can be achieved by
using a well-graded aggregate.
Mineral admixtures

Mineral admixtures forman essential part of the high-performanceconcrete
mix. These are used for various purposes, depending upon their properties.
More than the chemical composition, mineralogical and granulometric
characteristics determine the influence of mineral admixture's role in
enhancing properties of concrete. The fly ash (FA), the ground granulated blast
furnaceslag (GGBS) and the silica fume (SF) has been used widely as
supplementary cementations materials in high performanceconcrete. These
mineral admixtures, typically fly ash and silica fume (also called condensed
silica or micro silica), reduce the permeability of concrete to carbon dioxide
(CO2) and chloride-ion penetration without much changein the total porosity.
These pozzolanas reactwith OPC in two ways-by altering hydration process
through alkali activated reaction kinetics of a pozzolanas called pozzolanic
reaction and by micro filler effect. In pozzolanic reaction the pozzolanas react
with calcium hydroxide, Ca(OH)2, (freelime) liberated during hydration of
cement, which comprises up to 25 per cent of the hydration product, and the
water to fill voids with morecalcium-silicate-hydrate (non-evaporablewater)
that binds the aggregate particles together.
The pozzolanas may also react with other alkalis such as sodium and potassium
hydroxides presentin the cement paste. These reactions reduce permeability,
decrease the amounts of otherwise harmfulfree lime and other alkalis in the
paste, decrease free water content, thus increase the strength and improve
the durability.

Fly ash used as a partial replacement for cement in concrete, provides very
good performance. Concreteis durable with continued increasein compressive
strength beyond 28 days. Thereis little evidence of carbonation, it has low to
averagepermeability and good resistanceto chloride-ion penetration.
Chloride-ion penetration rating of high volumefly ash (HVFA) concrete is less
than 2000 coulombs, which indicate a very low permeability concrete.
Itcontinues to improvebecause many fly ash particles react very slowly,
pushing the coulomb value lower and lower. Silica fume not only provides an
extremely rapid pozzolanic reaction, but it’s very fine sizealso provides a
beneficial contribution to concrete. Silica fume tends to improveboth
mechanical properties and durability. Silica fume concretes continue to gain
strength under a variety of curing conditions, including unfavorableones. Thus
the concretes with silica fume appear to be more robustto early drying than
similar concretes that do not contain silica fume. Silica fume is normally used in
combination with high-rangewater reducers and increaseachievable strength
levels dramatically.

Since no interaction between silica fume, ground granulated blast-furnaceslag
and fly ash occurs, and each component manifests its own cementations
properties as hydration proceeds, higher strength and better flow ability can
be achieved by adding a combination of SF, FA and GGBFS to OPC which
provides, a systemwith wider particle-sizedistribution. HVFA concrete
incorporating SF exceeds performanceof concrete with only FA. The key to
developing OPC-FA-SF and OPC-GBSF-SF concretes withoutreduction in
strength is to incorporate within the mixture adequate amounts of OPC and
water. Using both silica fume and fly ash, the strength at 12 hours has been
found to improvesuddenly over similar mixes with silica fume alone. This
phenomenon has been attributed to the liberation of soluble alkalis from the
surfaceof the fly ash.
Admixtures
High Range Water Reducing Admixtures (HRWA) :These are the second
generation admixture and also called as Super plasticizers. These are synthetic
chemical products madefromorganic sulphonateof type RSO3, whereR is
complex organic group of higher molecular weight produced under carefully
controlled condition:
The commonly used super plasticizers are as follows:
I. Sulphonatemelamine formaldehyde condensate(S M F C)
II. Sulphonated naphthalene formaldehydecondensate(S N F C)
III. Modified ligno-sulphonates and other euphonic esters, acids etc.
IV. PolycarboxylateEther Polymer (PCE)

Reduction in W/c Ratio is as follows against the different water
reducers admixtures:
1) Water Reducer Admixture: 5-12% Reduction of water.
2) Melamine/Naphthalene based admixtures: Itreduces water 16-25 %.
3) Polycarboxylateether polymer based admixture: It reduces water 20 to
35%.
The main objectives for using super plasticizers are the following
I. To producehighly dense concreteto ensurevery low permeability
with adequate resistanceto freezing-hawing.
II. To minimizethe effect of heat of hydration by lowering thecement
content.
III. To produceconcretewith low air content and high workability to
ensurehigh bond strength.
IV. To lower the water-cementratio in order to keep the effect of
creep and shrinkageto a minimum.
V. To produceconcreteof lowestpossibleporosity to protect it
againstexternal attacks.
VI. To keep alkali content low enough for protection againstalkali-
aggregatereaction and to keep sulphate and chloride contents as
low as possiblefor prevention of reinforcementcorrosion.
VII. To producepump able yetnon-segregating typeconcrete.
VIII. To overcomethe problems of reduced workability in fiber
reinforceconcreteand concrete.

IX. To providehigh degree of workability to the concretes having
mineral additives with very low water-cementations material
ratios.
X. To producehighly ductile and acid resistantpolymer (acrylic latex)
concretewith adequate workability and strength.
OBJECTIVE
To achieve high strength concrete (M70) withoutcompromising the
workability of concrete. Normally when we try to achieve very high strength
the mix becomes very stiff and it can’tbe pumped on the site .Thus our main
aim was to achieve the desired strength with desired workability and other
properties like low permeability ,high durability etc.
CRITICAL STUDY OF THE FOLLOWING
Variations in compressivestrength with respectto water cement ratio and
varying proportions of cementation materials.

MATERIAL USED
 Cement(OPC Cement 43 grade)
 Fly Ash
 Micro Silica
 CoarseAggregates(20mm & 10mm)
 Fine Aggregates
 Water
 Admixture (Glenium 51)
Mix Design Detail of M-70
Target Mean Strength
Fck =fck+1.65 s
=70+1.65*5
= 78.25 MPa
Where,
fck’ – target averagecompressivestrength 28 days.
fck- Characteristic compressivestrength at 28 days
“S” is taken 5 for M30 or aboveas per IS 10262
Design for 1m3
batch.

FromTable-2 IS 10262
Maximum water content for 20 mm aggregate – 186 kg for (slump 25mm to
50mm)
Estimation of Water Content for 75mm SLUMP.
=186+(15/100)*186
=186+27.9
=213.9 kg/m3
Fromtrials it was found thatadmixture (super plasticizer) GleniumSKY 51
reduced water content by 30%.
Hence arrived water content=213.9*0.7
=149.73 kg/m3
*Note: modification in water content has been done in accordancewith the
standard lab result various trialmixtures for required slump/flow requirement
and strength, which are not specified in IS codes.
Calculation of Cementations Material
Fromtrial an error water cement ratio was found 0.26
Cementations Content: 149.73/0.26
= 576 kg/m3
Content of OPC : -0.77*576
=434 Kg/m3
Content of Fly Ash : -0.17*576
=98 kg/m3
Micro Silica : 0.06*576
=35 kg/m3

Volume of Coarse Aggregates and Fine Aggregates
Volume of 20mmaggregates = 0.23
Volume of 10mmaggregates = 0.35
Volume of Fine Aggregates = 1-(0.23+0.35) =0.42
Mix Calculation
Mix calculation per unit volume of Concrete as follows:
Volume of Concrete : 1m3
Volume of Cement : (Mass of Cement /Specific gravity)*(1/1000)
= (434/3.14)*(1/1000)
=0.138 m3
Volume of Fly Ash : (Mass of Fly Ash/Specific gravity)*(1/1000)
= (98/1.93)*(1/1000)
=0.050 m3
Volume of Micro silica : (Mass of Micro silica/ specific
Gravity)*(1/1000)
= (35/2.2)*(1/1000)
=0.0159 m3
Volume of Water = (Mass of Water/Specific Gravity of
Water)*(1/1000)
= (149.73/1)*(1/1000)
=0.149 m3
Volume of Admixture = (Mass of Glenium sky 777/Specific Gravity of
Admixtures)*(1/1000)
= (7.02/1.1)*(1/1000)

= 0.00638 m3
Volume of All in one Aggregates : (1-(0.138+0.050+0.0159+0.150))
=0.6471m3
Mass of CourseAggregates 20mm:
=0.6471*volumeof 20mm aggregates*Specific gravity*1000
=0.6471*0.23*2.60*1000
=386 kg/m3
Mass of Coarseaggregates 10 mm:
= 0.6471*volumeof 10mm aggregates *specific gravity*1000
=0.6471*0.35*2.59*1000
=586 kg/m3
Mass of fine aggregates:
= 0.6471 *volumeof fine aggregates*specific gravity*1000
=0.6471*0.42*2.55*1000
=693 kg/m3
Obtain Mix Proportion for Trial Mix
Cement : 434 kg/m3
Fly Ash : 98 kg/m3
Micro Silica : 35 kg/m3
Water : 149 kg/m3
Coarseaggregates 20 mm : 356 kg/m3
Coarseaggregates 10 mm : 586 kg/m3
Fine aggregates : 693 kg/m3
Water Cement Ratio : 0.26
Trial Mix Batch Of 0.03
Cement : 13.02 kg
Fly Ash : 2.94 kg
Micro Silica : 1.05 kg
Water : 4.47 kg
Coarseaggregates 20 mm : 10.95 kg

Fine aggregates : 20.76 kg
Two other trial mixes were as follows
BATCH A
Cement : 13.60 kg
Fly Ash : 1.7 kg
Water : 4.47 kg
BATCH B
Cement : 11.90 kg
Fly Ash : 3.40 kg
Water : 4.47 kg
Laboratory Tests
Various laboratory tests wereperformed during our training period has be
listed below with their obtained values and permissiblelimit.
1. Determination of Specific Gravity by Pycnometer Method.

PermissibleLimit- 2.4 to 2.9
Obtained Values
CoarseAggregate : 2.6
Fine Aggregate : 2.59
2. Determination of Moisture Content Of Aggregates
PermissibleLimit: Less than 2% for coarseaggregate and less than 2.3% for
fine aggregates.
Obtained Value
Coarseaggregate: 0.5%
Fine aggregate : 1.5%
3. Determination of ImpactValue of Coarseaggregate
PermissibleLimit: 30%
Obtained Value : 18.76%
3. Crushing Test
PermissibleLimit: 30%
Obtained Value : 17.67%
3. Determination of Initial and Final Setting Time of Cement
PermissibleLimit:
Initial Setting Time: As per IS Code it should not be less than 30 minutes
for general purpose.
Final Setting Time: As per IS Codeit should Not be more than 10 Hours.
Obtained Value
Initial Setting Time: 48 minutes
Final Setting Time: 6 hours 47 minutes.

Determination of Sieve Analysis of Aggregates
Sieve Analysis
Fine Aggregates
Sieve Size (mm) Weight Percentage Cumulative
%
passed Permissible Limit Remark
10 0 0 0 100 100 Passed
4.75 172 9.11 9.11 90.89 90 to 100
2.36 160 8.48 17.59 82.41 75 to 100
1.18 323 17.11 34.70 65.3 55 to 100
600 micro 243 12.11 46.81 53.19 35 to59
300 micron 752 39.85 86.66 13.34 8 to 30
150 micron 196 10.38 97.04 2.96 0 to 10
Pan 41 2.17 99.21 0.79 0
Sieve Analysis
20 mm Aggregates
Sieve Size
(mm) Weight Percentage Cumulative
%
passed
Permissible
Limit Remark
25 0 0 0 100 100 Passed
20 1858.995 9.81 9.81 90.19 85 to 100
10 1456.308 84.85 94.66 5.34 0 to 20
4.75 51.7335 4.73 99.39 0.61 0 to 5
PAN 11.5595 0.61 100 0 0
Sieve Analysis
10 mm Aggregates
Sieve Size Weight Percentage Cumulative % Permissible Remark

(mm) passed Limit
25 0 0 0 100 100 Passed
20 1858.995 9.81 9.81 90.19 85 to 100
10 1588.958 83.85 93.66 6.34 0 to 20
4.75 104.7935 5.53 99.19 0.81 0 to 5
PAN 15.3495 0.81 100 0 0

Test Results

Graphical Representation of Data
0
10
20
30
40
50
60
70
0.25 0.26 0.27 0.28 0.29 0.3 0.31 0.32 0.33
CompressiveStrength(MPa)
W/C ratio
28 days Strength Vs W/C Ratio

Conclusion
 Our target was to achieve M 70 gradeconcrete but wecould reach up to
a compressivestrength of 71.21MPa.
 But due poor workmanship and professionalinexperiencewe were not
able to achieve desired compressivestrength; however wewereable to
achieve compressiveStrength of 71.21MPa which was quitecloser to
our results. Added to that we carried outs trial mixes at various water
cement ratios(0.32-0.26) which helped us in understanding the behavior
of concreter at lower water cement ratio which was displayed in graphs
in previous slides.
 We also understood there are various uncertainties associated with the
concrete mix design and even smaller or minor things could be crucial
and may affect the behavior of concrete.

High strength m70 concrete grade

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High strength m70 concrete grade