Self Compacting Concrete Using Flyash And Glass Fibre

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 1

INTRODUCTION Self Compacting Concrete are concretes that can flow under its own weight to completely fill the formwork and passes through the congested reinforcement without segregation and compact without any mechanical vibration. Several studies in the past have revealed the usefulness of fibres to improve the structural properties of concrete like ductility, post crack resistance, energy absorption capacity etc. Fibre reinforced self compacting concreting combines the benefits of self compacting concrete in fresh state and shows an improved performance in the hardened state due to the addition of fibres.

1.1 History SCC was developed in University of Tokyo, Japan by Okamura in the late 1980's to be mainly used for highly congested reinforced concrete structures recognising the lack of uniformity and difficulty in complete compaction of concrete by vibration. By the early 1990‟s, Japan has developed SCC that does not require vibration to achieve full compaction. By the year 2000, the SCC has become popular in Japan for prefabricated products and ready mixed concrete. Since then SCC has generated tremendous interest amongst the research scholars and engineers. Several European countries recognised the significance and potentials of SCC developed in Japan. During 1989, they found the European federation of natural trade associations representing producers and applicators of specialist building products (EFNARC). The utilisation of self-compacting concrete started growing rapidly. EFNARC, making use of broad practical experiences of all members of European federation with SCC, has drawn up specification and guidelines to provide a framework for design and use of high quality SCC, during 2001. Current trend in the building industry shows increased construction of large and complex structures, which leads to difficult concreting conditions. When large quantity of heavy reinforcement is to be placed in reinforced concrete members it is difficult to Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE ensure that the form work gets completely filled with concrete that is fully compacted without voids or honeycombs. Vibrating concrete in congested locations may cause some risk to labour and there are always doubts about the strength and durability of concrete placed in such locations. One solution for the achievement of durable concrete structures independent of the quality of construction work is the use of Self Compacting Concrete (SCC). SCC is concrete which can flow under its own weight and completely fill the formwork without segregation, without any vibration maintaining homogeneity.

1.2 Use of Fibres Though concrete possesses high compressive strength, stiffness, low thermal and electrical conductivity and low combustibility two characteristics, have limited its use: it is brittle and weak in tension. The development of fibre-reinforced composites (FRC) has helped in improving these deficiencies. Fibres are small pieces of reinforcing material added to a concrete mix as a means of arresting the crack growth. The most common fibres used are steel, glass, asbestos and polypropylene .When the loads imposed on concrete approach that for failure, cracks will propagate, sometimes rapidly; fibres in concrete provide a means of arresting the crack growth. If the modulus of elasticity of the fibre is high with respect to the modulus of elasticity of the concrete or mortar binder, the fibres help to carry the load, thereby increasing the tensile strength of the material. Fibres improve the toughness, the flexural strength, reduces creep, strain and shrinkage of concrete. The fibre used in this study is glass fibre. Glass Fibre Reinforced Concrete (GFRC) is composed of concrete, reinforced with glass fibres to produce a thin, lightweight and strong material. Glass fibres are noncorrosive, nonconductive, nonmagnetic, low-density, and high-modulus and when added to the polymer matrix, the fibre-reinforced polymer is made suitable for many more applications. Addition of fibres to cement concrete has little effect on its pre cracking behaviour, but it does substantially enhance the post cracking response, which leads to improved ductility and toughness. Studies have shown that the addition of glass fibres, organic fibres, and steel fibres into cement concrete and cement mortar improved the toughness, ductility, tensile, flexural and impact strength. Even though concrete has been used since ages, Glass Fibre Reinforced Self Compacting Concrete (GFRSCC) is still a relatively new invention. GFRSCC has high Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Compressive and flexural strengths, ability to reproduce fine surface details, low maintenance requirements, low coefficients of thermal expansion, high Fire resistance, and environmentally friendly. The strength of GFRC is usually determined by glass content, fibre size, fibre compaction, distribution and orientation. Considering the advantages of SCC and GFRC an attempt has been made to combine these two and to produce Glass Fibre Reinforced Self Compacting Concrete (GFRSCC) and to study the mechanical properties of both SCC and GFRSCC incorporating fly ash as the mineral admixture.

1.3 Advantages of SCC Self compacting concrete (SCC) can be classified as an advanced construction material. The SCC as the name suggests, does not require to be vibrated to achieve full compaction. This offers following benefits and advantages over conventional concrete. 

Improved quality of concrete and reduction of onsite repairs.



Faster construction times.



Lower overall costs. Even though the initial cost of SCC is comparatively higher than the conventional concrete. Considering the long service of the structure, minimum maintenance, labour cost, and cost due to the vibrators required, benefit cost ratio is very much in favour in case of SCC.



Improvement of health and safety is also achieved through elimination of handling of vibrators.



The uses of pozzolanic materials, such as slag, fly ash, silica fume, etc., will help SCC more durable, otherwise these are waste products demanding with no practical applications and which are costly to dispose of.



Self compacting concrete is ideal for concrete parts with complicated shapes and elements with high quality visible concrete.



Ease of placement results in cost savings through reduced equipment and labour requirement.



SCC makes the level of durability and reliability of the structure independent from the existing on – site conditions relate to the quality of labour, casting and compacting systems available.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE 

The high resistance to external segregation and the mixture self – compacting ability allow the elimination of macro – defects, air bubbles, and honey combs responsible for penalizing mechanical performance and structure durability.



Better surface finishes.



Easier placing.



Thinner concrete sections.



Greater Freedom in Design.

1.4 Disadvantages of SCC The main disadvantages of SCC are: 

The production of SCC places more stringent requirements on the selection of materials in comparison with conventional concrete.



An uncontrolled variation of even 1% moisture content in the fine aggregate will have a much bigger impact on the rheology of SCC at very low w/c ratio. Proper stock piling of uniformity of moisture in the batching process and good sampling practice are essential for SCC mixture.



A change in the characteristics of a SCC mixture could be a warning sign for quality control and while a subjective judgement, may sometimes be more important than the quantitative parameters.



The development of a SCC requires a large number of a trial batches. In addition to the laboratory trial batches, field size trial batches should be used to simulate the typical production conditions. Once a promising mixture has been established, further laboratory trial batches are required to quantify the characteristics of the mixture.



SCC is costlier than conventional concrete initially based on concrete materials cost due to higher dosage of chemical admixtures, i.e. high range water reducer and viscosity enhancing admixture. Increase in material cost can be easily offset with improvement in productivity, reductions in vibration cost and maintenance and proper uses of mineral admixtures.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

1.5 How Economical Is Self Compacting Concrete? SCC is slightly expensive than conventional concrete. It is seen that cost of materials of SCC is about 10-15 percent higher. On the other hand there are considerable savings. 

The energy consumption is reduced to about 10%nas no vibration is required



Cost of compaction and labourers are reduced.



Cost of maintenance and finishing is also reduced. Considering all above points it is calculated that cost of SCC has only slight

increase than the conventional concrete. By the introduction of SCC the quality of finished product is improved.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 2

LITERATURE REVIEW T. Suresh Babu, M.V. Seshagiri Rao and D. Rama Seshu[1] presented the design mix of M 30 grade of Glass fibre self compacting concretes. In this investigation Cem-FIL anti-crack high dispersion glass fibres were added to self compacting concrete and Glass Fibre Reinforced Self Compacting Concrete was developed to study mechanical properties and stress-strain behaviour of self compacting concrete and glass fibre reinforced self compacting concrete. A strength based mix proportion of self compacting concrete was arrived based on Nan-Su method of mix design and the proportion was fine tuned by using Okamura‟s guidelines. Five self compacting concrete mixes with different mineral admixtures like fly ash, ground granulated blast furnace slag and rice husk ash were taken for investigation with and without incorporating glass fibres. A marginal improvement in the ultimate strength was observed due to the addition of glass fibres to the self compacting concrete mix. Also incorporation of glass fibres had enhanced the ductility of self compacting concrete. Complete Stress-Strain behaviour has been presented and an empirical equation is proposed to predict the behaviour of such concrete under compression. Prajapati Krishnapal, Chandak Rajeev and Dubey Sanjay Kumar[2] in their work presented the properties of self compacting concrete, mixed with fly ash. Polycarboxylic ether based super plasticizer Fairflo RMC (M) supplied by Fairmate Chemicals Pvt. Ltd. was used. 10%, 20%, 30% weight of cement is replaced by equal weight i.e. 10%, 20%, 30% weight of fly ash respectively. The test results for acceptance characteristics of self-compacting concrete such as slump flow; V-funnel and L-Box are presented. Further, compressive strength at the ages of 7, 28 days was also determined. The result shows that slump flow improves with the increase in cement replacement by fly ash. That is addition of fly ash in mix increases filling and passing ability of concrete, whereas superplasticizer imparts workability to concrete improving segregation resistance of concrete. And increase in fly ash content in place of cement reduced the water requirement of mix, thereby decreasing the 28 days the strength of concrete from 52MPa to 39MPa.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE P Srinivasa Rao, G K Vishwanadh, P Sravana, T Seshadri Sekhar[3] studied the flexural behaviour of reinforced concrete beams. An attempt has been made to study the strength behaviour of fibre reinforced SCC structural subjected to flexure for various grades of concrete mixes of M 30 , M 40 , M 50 and M 60 grade of Concrete M40, M 50 and M 60 with varying percentages of glass fibres from 0 % to 0.1% . Cem-FIL Anti – Crack HD glass fibres were used. Fly Ash as used as replacement for cement. The result shows that Glass Fibres in Reinforced Self Compacting Concrete slabs have not improved in flexure because of the reason that the glass fibres are small in diameter and smooth in nature It can be seen that the presence of Glass Fibres in Reinforced Self Compacting Concrete beams have not improved in flexure because of the reason that the glass fibres are small in diameter and smooth in nature. The ultimate load carrying capacity of glass fibre reinforced self compacting concrete beams with 0.03% glass fibres are more than reinforced self compacting concrete beams without glass fibres. B. Krishna Rao, V. Ravindra[4] compared the properties of plain normal compacting concrete and Self Compacting Concrete with steel fibre in their investigation. The self-compacting mixtures had a cement replacement of 35% by weight of Class F fly ash. Three different values of percentage of volume fraction of steel fibres (0.5%, 1.0% and 1.5%) were used. Result shows that fibre inclusion did not significantly affect the measured mechanical properties. The maximum strength improves as the fibre content increases from 0.5 to 1.0%, and from 1 to 1.5%decreases. However, only marginal increase is noticed in the ultimate strength. On the other hand maximum compressive, split tensile and flexural strength is found to increase markedly and maximum increase is about 7.20%, 11.07% and 8.77% at 90days. SFRSCC mixes show higher compressive, split tensile and flexural strength rather than normal compacting concrete. M Chandrasekhar, M V Seshagiri Rao, Maganti Janardhana[5] done a comparative study of stress-strain behaviour of M30 grade glass fibre reinforced self compacting Concrete (GFRSCC) and steel fibre reinforced self compacting concrete (SFRSCC). Analytical stress-strain models were proposed to predict the stress-strain behaviour of both GFRSCC and SFRSCC and observed that there were improvements in ductility factors for both GFRSCC and SFRSCC. The compressive strength of concrete was improved by 6.23% for GFRSCC and 7.13% for SFRSCC. GFRSCC and SFRSCC

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE showed a gradual reduction in stress with increase in strain when compared to plain SCC indicating more strain absorbing capacity. Guru Jawahar, C. Sashidhar, I.V. Ramana Reddy and J. Annie Peter[6] studied the design of self compacting concrete (SCC) mix with a SCC mix having 28% of coarse aggregate content and 35% replacement of cement with class F fly ash. The fresh state properties like slump flow, V-funnel test and L-box were carried out. And it was observed that the mix has met the acceptance criteria specified by EFNARC.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 3

CHARACTERISTICS OF SCC Self-compacting mixes are designed to have fresh properties that have a higher degree of workability than convectional concrete. Workability is a way of describing the performance of concrete in the plastic state and for SCC, workability is often characterized by the following properties: i.

Filling ability: ability to fill a formwork under its own weight

ii.

Passing ability: ability to overcome obstacles like reinforcement, small openings under its own weight without hindrance.

iii.

Stability (segregation resistance): homogeneous composition of concrete during and after the process of transportation and placing.

A concrete can be characterized as an SCC only if all three of these properties exist.

3.1 Filling Ability Filling ability, or flow ability, is the ability of the concrete to completely flow (horizontally and vertically upwards if necessary) and fill all spaces in the formwork under its own weight, without the addition of any external compaction. The flow ability of SCC is characterized by the concrete‟s fluidity and cohesion. It is often assessed using the slump flow test.

3.2 Passing Ability Passing ability is the ability of the concrete to flow though restricted spaces (e.g. dense reinforcement) without segregation, loss of uniformity or without blocking. This property is related to the maximum aggregate size and aggregate volume, and the L-Box test is the most common method used to asses this property. As the distance between particles decreases, the potential for blocking increases due to particle collisions and the build-up in internal stresses. Inter-particle interaction can be reduced by decreasing the coarse aggregate volume, and it has been shown that the energy required to initiate flow is often consumed by the increased internal stresses and coarse aggregates. Therefore, the aggregate content should be reduced in order to avoid blockage. Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

3.3 Segregation Resistance Stability, or resistance to segregation, is the ability of the concrete to remain uniform and cohesive throughout the entire construction process (mixing, transporting, handling, placing, casting, and etc). There should be minimum segregation of the aggregates (both fine and coarse) from the matrix and little bleeding. Segregation resistance is largely controlled by viscosity, and if the aggregates segregate then this could lead to blockage, therefore the viscosity of the paste should also be high enough to prevent segregation that may occur due to the increased aggregate content. Bleeding is a special case of segregation in which water moves upwards and separates from the mix. Some bleeding is normal for concrete, but excessive bleeding can lead to a decrease in strength, high porosity, and poor durability particularly at the surface. Stability is largely dependent on the cohesiveness and viscosity of the concrete mixture, and cohesiveness and viscosity can be increased by reducing the free water content and increasing the amount of fines. In order to ensure adequate stability, there are two basic mixture-proportioning methods: using a low water/cement ratio (w/c) and high content of fines, or by incorporating a viscosity-modifying admixture (VMA). Table 3.1 List of Test Methods for Workability Properties of SCC Property

Test Methods Slump flow

Filling Ability

T 50cm slump flow V Funnel L Box

Passing Ability

U box Fill Box

Segregation resistance

GTM test V funnel at T5 min

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

3.4 Test Setup and Methods 3.4.1 Slump Flow Test and T50 Slump Flow Test This test is used to measure the free horizontal flow of SCC on a plain surface without any obstruction. Concrete poured in slump cone without external compaction is made to flow on flow table. Time required for the concrete to cover 50 cm diameter spread circle (T50 cm time) from the time the slump cone is lifted is noted. Average flow of concrete after concrete stops flowing is measured to ascertain the slump flow value.

Fig. 3.1 Abraham‟s cone It is most commonly used test and gives a good assessment of filling ability and indications on stability of the mix. In case of unstable mix, most of the coarse aggregate particles remain in the centre of the flow table and only cement mortar flows. Absences of uniform distribution of larger particles across the spread indicate the poor viscosity of the mix. Intentional depressions created by finger, if not melded after removal of finger, indicate that the mix is segregated.

3.4.2 V-Funnel Test This test is conducted to assess the fluidity and segregation resistance of SCC. Inverted cone shaped equipment with 75 mm square opening at the bottom is used to assess the properties of mix such as unacceptable viscosity, undesirable volume of coarse aggregate, stability etc. V-funnel test is an important tool to assess the consistency of the mix. Uniformity in flow properties of fresh concrete during the production and before placement of concrete into the form can well be measured using V-funnel test. Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Fig. 3.2 V-Funnel To assess the consistency/fluidity of the mix, measurement of T 0 i.e., the time required for emptying the concrete filled V-funnel completely in seconds is measured by filling the funnel up to top with concrete without any external efforts and emptying immediately thereafter. A stable mix having T 0 in between 6 to12 seconds is considered to be satisfactory. Stability of the mix is ascertained by measuring the time (in seconds) required to empty the V-funnel completely 5 minutes after filling the funnel completely. This time is referred to as T 5. If the mix is segregated, T 5 time will be abnormally high as T 0 time. Interrupted flow is also observed in such cases. Fig.1 shows the flow of concrete with uniform distribution of coarse aggregates across the spread.

3.4.3 L-Box Test Method This test is conducted to assess the filling and passing ability of SCC. Uniformity of the mix is also examined by inspecting sections of the concrete in the horizontal section of „L‟ box. Apparatus as shown in Fig. 2 consist of rectangular box section in the shape of „L‟. Concrete is made to pass through the obstructions of known clearances. The vertical section is filled with concrete, and then the gate lifted to let the concrete flow into the horizontal section through vertically placed reinforcements. When the flow is stabilized, the height of concrete h1 (at obstructions) and h2 (at the end of horizontal section of „L‟) with respect to base are measured. The ratio of h2 and h1 referred to as Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE blocking value, a measure of passing ability of SCC, is calculated. Blocking value of a stable concrete 0.8 to 1.0 indicates better passing ability.

Fig 3.3 L-Box

3.4.4 Fill Box Test This device is used to measure the filling ability of SCC. It consists of a transparent rectangular box as shown in Fig. 3, with number of obstacles through which the concrete is let to flow. The apparatus is placed on a firm level support having a height of 1 meter approximately. Concrete is filled in the box through the funnel provided at the topside of the box till it covers the top-most obstacles at the rear end of the box. The height of the concrete at both the ends is measured to calculate volume of concrete filled. Compare the net volume of concrete filled with respect to the contained volume of the box up to the top of the top most obstacles, which gives the filling capacity of SCC.

3.4.5 ‘U’ Box Test This test is conducted to measure the filling ability of SCC. The equipment has the shape of English alphabet „U‟ that is divided by a middle wall into two compartments as shown in Fig. 4. An opening with a sliding gate is fitted between the two compartments with vertical reinforcements as obstructions. Concrete is made to flow through the obstruction and the level difference between the top surfaces of concrete in the both components is measured. Concrete is filled in one compartment up to the top. After one minute, the sliding gate is lifted to allow the concrete to flow into the other compartment Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE through reinforcement obstacles. After the concrete comes to the rest, the difference in height is measured. If filling ability of concrete is good, difference in height has to be less.

3.4.6 J-Ring test This test is used to determine the passing ability of the concrete. The equipment consists of a rectangular section (30mm x 25mm) open steel ring, drilled vertically with holes to accept threaded sections of reinforcement bar. These sections of bar can be of different diameters and spaced at different intervals: in accordance with normal reinforcement considerations, 3x the maximum aggregate size might be appropriate. The diameter of the ring of vertical bars is 300mm, and the height 100 mm. Table 3.2 Typical Acceptance Criteria for SCC Sl.

Method

Unit

1

Slump flow by Abram‟s cone

2

No.

Typical Ranges of Values Minimum

Maximum

Mm

650

800

T50 cm Slump flow

Sec

2

5

3

V-funnel

Sec

8

12

4

V-funnel at T5 minutes

Sec

0

3

5

L-Box

h2/h1

0.8

1.0

6

U-Box

(h2-h1) mm

0

30

7

Fill-Box

%

90

100

8

GTM Screen Stability Test

%

0

15

9

Orimet

Sec

0

5

10

J-ring

Mm

0

10

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 4

EXPERIMENTAL INVESTIGATION 4.1 Aim 1. To design mixes for self-compacting concrete mixed with fly ash incorporating glass fibre in various percentages and to study its fresh and hardened state concrete properties. 2. To compare the compressive strength at the ages of 7and 28 days, split tensile strength and flexural behaviour of self compacting concrete at 28 days with and without glass fibres for M20 and M30 grades of concrete mixes.

4.2 Material Properties 4.2.1 Cement Ordinary Portland cement of 53 grade was used and tested for physical and chemical properties and found to be conforming to various specifications as per IS: 12269-1987. Table 4.1 Physical Properties of Cement Sl. No 1

Tests on Cement

Observations

Specific gravity

3.15

2

Normal consistency

30%

3

Initial setting time 38

38 min

4

Compressive strength 7 days

33 N/mm2

14 days

52 N/mm2

28 days

61 N/mm2

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

4.2.2 Fine Aggregate The aggregate which is passing through 4.75 mm sieve is known as fine aggregate. Locally available river sand which is free from organic impurities is used sand passing through 4.75mm sieve and retained on 150 micron IS sieve is used in this investigation. The physical properties of fine aggregate like specific gravity, bulk density, gradation and fineness modulus is tested in accordance with IS: 2386-1975. Table 4.2 Sieve Analysis of Fine Aggregate Weight of sand sample taken = 1000g. Weight of

Cumulative

Cumulative%

Aggregate

Weight

of Weight

10 mm

Retained 0 (Gm)

Retained 0 (Gm)

Retained 0

4.75 mm

0

0

0

100

2.36 mm

10

10

1

99

1.18 mm

197.5

207.5

20.75

79.25

600 µ

371.0

578.5

57.85

42.15

300 µ

353.0

931.5

93.15

6.85

150 µ

68.5

1000.0

100.0

0

I.S. Sieve Size

% of Remarks Passing 100

Zone –II

Table 4.3 Properties of Fine Aggregate Properties

Observations

Fineness modulus

2.72

Specific gravity

2.65

Bulk density (Kg/m3)

1690

4.2.3 Coarse Aggregate The crushed coarse aggregate of 20 mm maximum size rounded obtained from the local crushing plant; (Bidadi, Karnataka) is used in the present study. The physical properties of coarse aggregate like specific gravity, bulk density, gradation and fineness modulus are tested in accordance with IS : 2386-1975.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Fig 4.1 Coarse Aggregate Table 4.4 Sieve Analysis of Coarse Aggregate Weight

I.S. Sieve Size

Cumulative

of Aggregate Weight Retained

Cumulative

% of

% of Weight

Passing

Retained

(gm)

Retained

40mm

0 (gm)

0

0

100

20mm

1240

1240

12.40

87.60

12.5mm

8260

9500

95.00

5.00

10mm

290

9790

97.90

2.10

8mm

120

9910

99.10

0.8

6.3mm

40

9950

99.50

0.5

4.75mm

20

9970

99.70

0.3

30

10000

-

0

Pan 75 nu

Fineness modulus of coarse aggregate = 503/100 =5.03 Table 4.5 Properties in Coarse Aggregate Properties

Observations

Fineness modulus

5.03

Specific gravity

2.70

Bulk density (kg/m3)

1460

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

4.2.4 Glass Fibre

Fig. 4.2 Glass fibre The fibre used in this study is the glass fibre with 20-25mm in length & diameter = 1.52.3mm. 4.2.4.1 Properties of Commercially Available Glass Fibres: 1. Length

: Graded

2. Melting Point

: 165 ͦ C

3. Acid Resistance

: High

4. Salt Resistance

: High

5. Electrical Conductivity

: Low

6. Elongation

: 12 – 15%

7. Construction

: Fibrillated

8. Absorption

: Nil

9. Alkali Resistance

: Full

10. Thermal Conductivity

: Low

11. Tenacity

: 4 – 5.5 GPD

12. Specific Gravity

: 0.92 g/cc

4.2.4.2 Functions 1. Reinforcement against shrinkage and intrinsic cracking. 2. Replaces welded wires mesh/ secondary cracks control steel used for crack prevention of concrete flooring. 3. Reduces bleeding and dust formation in concrete. 4. Improves Impact Resistance 3-4 times. 5. Improves abrasion resistance by 30-40%. 6. Gives residual strength to concrete.

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE 7. Improves residual strength of concrete- thus avoids sudden failures and make the concrete earth-quake resistant. 8. Reduce permeability, thus protects rebar from corrosion. 9. Makes the concrete more durable. 10. Makes hardened concrete more tough.

4.2.5 Fly Ash Fly ash is obtained from Raichur Thermal Power Station at Raichur, Karnataka. The physical and chemical properties of fly ash are given in the table 2 and table 3, respectively and conform to IS: 3812-2003. Table 4.6 Physical Properties of Fly Ash Physical Properties

Test Results

Colour

Grey (Blackish)

Specific Gravity

2.27

Table 4.7 Chemical Properties of Fly Ash Sl.

Parameters

Results (%)

No 1

Silicon dioxide (SiO2)

57.6

2

Magnesium oxide (MgO )

1.63

3

Total sulphur as sulphur trioxide( SO3)

0.07

4

Available alkalis as sodium oxide ( Na 2O)

1.2

5

Loss on ignition

2.17

4.2.6 Water As per IS 456:2000, water used for both mixing and curing should be free from injurious amount of deleterious materials. Portable water (tap water) is generally considered satisfactory for mixing and curing concrete. Ghousia College of Engineering, Ramanagaram

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A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

4.2.7 Admixture: Glenium B233 Glenium B233 is an admixture of a new generation based on modified polycarboxylic ether. The product has been primarily developed for applications in high performance concrete where the highest durability and performance is required. Glenium b233 is free of chloride & low alkali. It is compatible with all types of cements. 4.2.7.1 Uses 

Production of rheodynamic concrete.



High performance concrete for durability.



High early and ultimate strength concrete.



High workability without segregation or bleeding.



Precast & Pre-stressed concrete.



Concrete containing pozzolonas such as microsilica, GGBS, PFA including high volume fly ash concrete.

4.2.7.2 Advantages 

Elimination of vibration and reduced labor cost in placing.



Marked increase in early & ultimate strengths.



Higher E modulus.



Improved adhesion to reinforcing and stressing steel.



Better resistance to carbonation and other aggressive atmospheric conditions.



Lower permeability-increased durability.



Reduced shrinkage and creep.

4.2.7.3 Description Glenium B233 has a different chemical structure from the traditional super plasticisers. It consists of a carboxylic ether polymer with long side chains. At the beginning of the mixing process it initiates the same electrostatic dispersion mechanism as the traditional superplasticisers, but the side chains linked to the polymer backbone generates a steric hindrance which greatly stabilises the cement particles' ability to separate and disperse. Steric hindrance provides a physical barrier (alongside the electrostatic barrier) between the cement grains. With this process, flowable concrete with greatly reduced water content is obtained. Ghousia College of Engineering, Ramanagaram

Page 20

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE The product shall have specific gravity of 1.08 & solid contents not less than 30% by weight. The product shall comply with ASTM C494 Type F and shall be free of lignosulphonates, naphthalene salts and melamine formaldehyde when subjected to IR Spectra. It is a ready-to-use liquid which is dispensed into the concrete together with the mixing water. The plasticising effect and water reduction are higher if the admixture is added to the damp concrete after 50 to 70% of the mixing water has been added. The addition of Glenium B233 to dry aggregate or cement is not recommended. 4.2.7.4 Workability GLENIUM B233 ensures that rheoplastic concrete remains workable in excess of 45 minutes at +25°C. Workability loss is dependent on temperature, and on the type of cement, the nature of aggregates, the method of transport and initial workability. 4.2.7.5 Typical Properties Aspect

: Light brown liquid

Relative Density

: 1.08 ± 0.01 at 25°C

pH

:

>6

Chloride ion content : < 0.2% 4.2.7.6 Effects Of Over Dosage A severe over-dosage of glenium B233 can result in the following:  Extension of initial and final set.  Bleed/segregation of mix, quick loss of workability.  Increased plastic shrinkage.

4.3 Instruments Casted V- Funnel and L- Box were fabricated as per specifications for determining the characteristics of SCC.

Ghousia College of Engineering, Ramanagaram

Page 21

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

4.4. Mix Proportions 4.4.1 Mix Design – M20 Grade 4.4.1.1 Design Stipulations 1.

Characteristic compressive strength required in the field at 28-days

= 20 MPa

2.

Maximum size of aggregate

= 20 mm

3.

Degree of workability

= 0.9 (compaction factor)

4.

Degree of quality control

= Good

5.

Type of exposure

= Severe

4.4.1.2 Test Data of Materials 1. 2.

Specific gravity of cement Compressive strength of cement: Satisfies the requirements at 7 days

3.

4.

5.

6.

= 3.15

: as per IS: 269-1989

Specific gravities of Coarse aggregate

= 2.70

Fine aggregate

= 2.65

Water absorption Coarse aggregate

= 0.5%

Fine aggregate

= NIL

Free surface moisture Coarse aggregate

= NIL

Fine aggregate

= 2.0%

Grading of aggregates

: Conforming to zone II of IS 389-1970

4.4.1.3 Target Strength for Mix Proportioning Fck = fck +1.65s Where, Fck = target average compressive strength at 28 days Ghousia College of Engineering, Ramanagaram

Page 22

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE fck = characteristic compressive strength at 28 days s = standard deviation (as per IS: 456-2000 clause 9.2.4.2) From Table 1, standard deviation, s = 4 N/mm2 Therefore, Fck = 20 + 1.65 × 4 = 26.60 N/mm2 4.4.1.4 Selection of Water-Cement Ratio From Table 5 of IS 456, maximum water-cement ratio = 0.55. Based on experience, adopt water-cement ratio as 0.50. 0.50 < 0.55 Hence OK. 4.4.1.5 Selection of Water and Sand Content Selection of water and sand content for 20mm maximum size aggregate and the sand confirming to ZONE -II. For w/c-0.5, C.F-0.8, angular, sand confirming to ZONE-11. a) Water content per cubic meter of concrete = 186 l/m3 b) Sand content as percentage of total aggregate by absolute volume = 35% c) C.F. = 0.9 SI No 1

Change in conditions

Adjustment required

Adjustment required

in water content

in sand content

0

-2.0%

+3%

0

3%

-2%

For decrease in w/c ratio by (0.6-0.5) i.e. 0.10

2

For increase in compacting factor (0.9-0.8) i.e. 0.10

3

Total

Therefore required sand content as percentage of total aggregate by volume = 35-2.0=33% 6 Estimated water content for 100 mm slump = 186 + 100

Ghousia College of Engineering, Ramanagaram

× 186 0

= 197.16litre Page 23

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE As superplasticizer is used, the slump can be increased. 4.4.1.6 Calculation of Cement Content Water-cement ratio

= 0.40

Cement content

=

197.16 0.50

= 394.32 kg/m3

From Table 5 of IS 456, minimum cement content for severe exposure condition = 320 kg/m3 394.32 kg/m3>320 kg/m3.Hence OK. 4.4.1.7 Determination of Coarse and Fine Aggregates From IS: 10262-1982, Table 3, for the specified maximum size of aggregate of 20 mm, the amount of entrapped air in the wet concrete is 2 percent.

V= W +

C Sc

fa + P ×S

1

fa

× 1000

Where, V =1–

2 100

V = 0.98 0.98 = [197.16+ (394.32/3.15) + fa/ (0.33×2.65)]×1/1000] Fine aggregate, fa = 575.12 kg/m3

V= W +

C Sc

+

Ca 1−P S ca

1

× 1000

0.98= [197.16+ (394.32/3.15) Ca / ((1-0.33)×2.65)×1/1000] Coarse aggregate, Ca =1189.8 kg/m3

Ghousia College of Engineering, Ramanagaram

Page 24

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE The mix proportion per cubic meter of concrete then becomes Water

Cement

Fine Aggregate

Coarse Aggregate

197.16 litres

394.32 kg

575.12 kg

1189.80 kg

0.5

:

1

:

1.46

:

3.02

4.4.1.8 Converting Into SCC Proportions The normal concrete mix proportions are modified as per EFNARC specifications and different trail mixes and cast. By considering the fresh properties and harden properties of the mixes we finally arrived at the SCC mixed proportions as Cement

= 394.32 kg/m3

Fine aggregate

= 575.12 kg/m3

Coarse aggregate

= 1189.8 kg/m3

Total aggregate (T.A) = 575.12+1189.8 = 1764.92 kg/m3 Taking 55% of T.A as F.A F.A = 1764.92×0.55 = 970.71 kg/m3 C.A= 794.21 kg/m3 The modified proportion per cubic metre of concrete is Water

Cement

Fine Aggregate

Coarse Aggregate

197.16 litres

394.32 kg

970.71 kg

794.21 kg

0.5

:

1

:

2.46

Ghousia College of Engineering, Ramanagaram

:

2.01

Page 25

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

4.4.2 Mix Design – M30 Grade 4.4.2.1 Design Stipulations 1. Characteristic compressive strength required in the = 30 MPa

field at 28-days 2. Maximum size of aggregate

= 20 mm

3. Degree of workability

= 0.9 (compaction factor)

4. Degree of quality control

= Good

5. Type of exposure

= Severe

4.4.2.2 Test Data of Materials 1. Specific gravity of cement

= 3.15

2. Compressive strength of cement: Satisfies the : satisfies the requirements as per requirements at 7 days

IS: 269-1989

3. Specific gravities of Coarse aggregate

= 2.70

Fine aggregate

= 2.65

4. Water absorption

5.

Coarse aggregate

= 0.5%

Fine aggregate

= NIL

Free surface moisture Coarse aggregate

= NIL

Fine aggregate

= 2.0%

6. Grading of aggregates

: Conforming to zone II of IS 389-1970

4.4.2.3 Target Strength for Mix Proportioning Fck = fck +1.65s Where, Fck = target average compressive strength at 28 days fck = characteristic compressive strength at 28 days Ghousia College of Engineering, Ramanagaram

Page 26

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE s = standard deviation (as per IS: 456-2000 clause 9.2.4.2) From Table 1, standard deviation, s = 5 N/mm2 Therefore, Fck = 30 + 1.65 × 5 = 38.25 N/mm2 4.4.2.4 Selection of Water-Cement Ratio From Table 5 of IS 456, maximum water-cement ratio = 0.50. Based on experience, adopt water-cement ratio as 0.45. 0.45 < 0.50, hence OK. 4.4.2.5 Selection f Water and Sand Content Selection of water and sand content for 20mm maximum size aggregate and the sand confirming to ZONE -II. For w/c-0.6, C.F-0.8, angular, sand confirming to ZONE-11. a) Water content per cubic meter of concrete = 186 l/m3 b) Sand content as percentage of total aggregate by absolute volume = 35% c) C.F. = 0.9 SI

Change In Conditions

No 1

Adjustment Required

Adjustment Required

In Water Content

In Sand Content

0

-2.0%

+3%

0

3%

-2%

For decrease in w/c ratio by (0.6-0.45) i.e. 0.15

2

For increase in compacting factor (0.9-0.8)=0.10

3

Total

Therefore required sand content as percentage of total aggregate by volume = 352.0=33% 6 Estimated water content for 100 mm slump = 186 + 100

× 186

= 197.16litre Ghousia College of Engineering, Ramanagaram

Page 27

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE As superplasticizer is used, the slump can be increased. 4.4.2.6 Calculation of Cement Content Water-cement ratio

= 0.45

Cement content

=

197.16 0.45

= 438.13 kg/m3 From Table5 of IS: 456-2000, minimum cement content for severe exposure condition = 320 kg/m3 438.13 kg/m3 > 320 kg/m3. Hence OK. 4.4.2.7 Determination of Coarse and Fine Aggregates From IS: 10262-1982, Table 3, for the specified maximum size of aggregate of 20 mm, the amount of entrapped air in the wet concrete is 2 percent.

V= W +

C Sc

fa + P ×S

1

fa

× 1000

Where, V =1–

2 100

V = 0.98 0.98 = [197.16+ (438.13/3.15) + fa/ (0.33×2.65)]×1/1000] Fine aggregate, fa = 562.96 kg/m3

V= W +

C Sc

+

Ca 1−P S ca

1

× 1000

0.98= [197.16+ (438.13/3.15) Ca / ((1-0.33)×2.65)×1/1000]

Ghousia College of Engineering, Ramanagaram

Page 28

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Coarse aggregate, Ca =1142.98 kg/m3 The mix proportion per cubic meter of concrete then becomes Water

Cement

Fine aggregate

Coarse aggregate

197.16 litres

438.13kg

562.96kg

1142.98 kg

0.45

:

1

:

1.29

:

2.60

4.4.2.8 Converting Into SCC Proportions The normal concrete mix proportions are modified as per EFNARC specifications and different trail mixes and cast. By considering the fresh properties and harden properties of the mixes SCC mixed proportions are = 438.13 kg/m3

Cement Fine aggregate

= 562.96 kg/m3

Coarse aggregate

= 1142.98 kg/m3

Total aggregate (T.A) = 562.96+1142.98 =1705.94 kg/m3 Taking 55% of T.A as F.A F.A = 1705.94×0.55 = 938.27 kg/m3 C.A= 767.67 kg/m3 The modified proportion per cubic metre of concrete is Water

Cement

Fine Aggregate

Coarse Aggregate

197.16 litres

438.13 kg

938.27 kg

767.67 kg

0.5

:

1

:

Ghousia College of Engineering, Ramanagaram

2.14

:

1.75

Page 29

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

4.5 SCC Mix Proportions with Glass Fibre Fly ash conforming to IS: 3812-2003 is used as 25% replacement for cement in every mix with various percentage of glass. Mixes SCC 1 (0% glass fibre), SCC 2 (0.5% glass fibre), SCC 3 (1.0% glass fibre), SCC 4 (1.5% glass fibre) and SCC 5 (2.0% glass fibre) of M20 grade and mixes SCC 6 (0% glass fibre), SCC 7 (0.5% glass fibre), SCC 8 (1.0% glass fibre), SCC 9 (1.5% glass fibre) and SCC 10 (2.0% glass fibre) of M30 grade as shown in table 1& 2 below were used. The amount of superplasticiser used is 1.1 % for M30 grade and 1.2 % for M20 Grade. Table 4.8 Mix Proportion for M20 Grade Mix

Cement

Fly Ash

Fine

Coarse

Water

Glass Fibre

Designation

kg/m3

(25 percent

Aggregate

Aggregate

kg/m3

To Total

Replacement)

kg/m3

kg/m3

Volume (%)

kg/m3 SCC 1

295.74

98.58

970.71

794.21

197.16

0

SCC 2

295.74

98.58

970.71

794.21

197.16

0.05

SCC 3

295.74

98.58

970.71

794.21

197.16

0.10

SCC 4

295.74

98.58

970.71

794.21

197.16

0.15

SCC 5

295.74

98.58

970.71

794.21

197.16

0.20

Table 4.9 Mix Proportion for M30 Grade Mix

Cement

Fly Ash

Fine

Coarse

Water

Glass Fibre

Designation

kg/m3

(25 percent

Aggregate

Aggregate

kg/m3

To Total

Replacement)

kg/m3

kg/m3

Volume (%)

kg/m3 SCC 6

328.60

109.53

938.27

767.67

197.16

0

SCC 7

328.60

109.53

938.27

767.67

197.16

0.05

SCC 8

328.60

109.53

938.27

767.67

197.16

0.10

SCC 6

328.60

109.53

938.27

767.67

197.16

0.15

SCC 10

328.60

109.53

938.27

767.67

197.16

0.20

Ghousia College of Engineering, Ramanagaram

Page 30

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 5

EXPERIMENTAL RESULTS AND ANALYSIS 5.1 Fresh State Properties The fresh state properties like slump flow, V-funnel test and L-box test has been carried out to determine the flowability and passability. And the test results has been tabulated in the table 10 below Table 5.1 Workability Test Results L-Box

SI

Mix

Slump Flow

T50cmslump

V-Funnel

No.

Designation

650-800mm

2-5 S

8-12 S

1

SCC 1

680

4

8

0.86

2

SCC 2

665

4

8

0.85

3

SCC 3

660

4

9

0.85

4

SCC 4

657

3

10

0.86

5

SCC 5

652

4

9

0.86

6

SCC 6

715

4

10

0.95

7

SCC 7

704

3

8

0.95

8

SCC 8

698

3

9

0.9

9

SCC 9

690

4

9

0.9

10

SCC 10

685

4

10

0.9

Ratio 0.8-1.0

5.2 Specimen Details The specimens casted are a) Cubes of 150mm×150mm×150mm size b) Cylinder of 150mm dia×300mm length c) Prism of 100mm×100mm×500mm size

Ghousia College of Engineering, Ramanagaram

Page 31

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

5.3 Casting of Specimen The test moulds of size 150mm×150mm×150mm, 150mm dia×300mm length and 100m×100mm×500mm are used for casting of cubes, cylinders and prisms respectively. The moulds were cleaned and greased properly. The moulds were filled with concrete without any tamping since it is self compacting concrete. The top surface was made smooth after filling and the mould was kept unaltered for 24 hours before keeping it for curing.

5.4 Curing of Specimens All the specimens were kept for curing in a water tank for the required time period. Potable water was used for curing.

5.5 Hardened State Properties of SCC 5.5.1 Test for Compressive Strength The compressive strength of concrete is often considered the most important property of concrete, and is the most common measure used to evaluate the quality of hardened concrete. Compressive strength can be defined as the measured maximum resistance of a concrete specimen to axial loading.

Fig 5.1 Compression Testing Machine In this investigation self compaction concrete cubes of 150mm150mm×150mm size were used for testing the compressive strength. The cubes were tested in a compression testing machine of capacity 2000KN. Ghousia College of Engineering, Ramanagaram

Page 32

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Compressive strength is calculated by fc =

𝐏 𝐀

where, fc = Cube compressive strength in N/mm2 P

= Cube compressive failure in N

A = Cross-sectional area of cube The compressive strength value of different samples has been tabulated in the Table 5.2 to Table 5.21 below. Table 5.2 Compressive Strength of SCC 1 (7 Days) No. of Cube

Weight of Cube in 'gm'

Age of Cube In Days

Area of Cube cm2

Load 'P' in Ton

Compressive Strength N/mm2

1

7800

7

225

35

15.5

2

7850

7

225

32

14.0

3

7790

7

225

33

14.6

Average Compressive Strength N/mm2

14.2

Table 5.3 Compressive Strength of SCC 1 (28 Days) No. of Cube

Weight of Cube In 'gm'

Age of Cube In Days

Area of Cube Cm2

Load 'P' In Ton

Compressive Strength N/mm2

1

8050

28

225

66

29.3

2

8000

28

225

69

30.6

3

7900

28

225

68

30.2

Ghousia College of Engineering, Ramanagaram

Average Compressive Strength N/mm2

30.03

Page 33

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.4 Compressive Strength of SCC 2 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7800

7

225

38

16.8

2

7850

7

225

36

16.0

3

7790

7

225

40

17.7

16.83

Table 5.5 Compressive Strength of SCC 2 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Load 'P' In Ton

2

Cm

Compressive

Average

Strength

Compressive

2

N/mm

Strength N/mm2

In 'gm' 1

8050

28

225

70

31.1

2

8000

28

225

74

32.8

3

7900

28

225

76

33.7

32.5

Table 5.6 Compressive Strength of SCC 3 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7700

7

225

40

17.77

2

7500

7

225

42

18.67

3

7650

7

225

38

16.89

Ghousia College of Engineering, Ramanagaram

17.77

Page 34

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.7 Compressive Strength of SCC 3 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7950

28

225

72

32.0

2

8000

28

225

75

33.3

3

7900

28

225

76

33.78

33.02

Table 5.8 Compressive Strength of SCC 4 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Load 'P' In Ton

2

Cm

Compressive

Average

Strength

Compressive

2

N/mm

Strength N/mm2

In 'gm' 1

8150

7

225

34

15.11

2

7900

7

225

39

17.33

3

7850

7

225

36

16.0

16.14

Table 5.9 Compressive Strength of SCC 4 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

8250

28

225

75

33.33

2

8100

28

225

72

32.0

3

8000

28

225

70

31.11

Ghousia College of Engineering, Ramanagaram

32.14

Page 35

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.10 Compressive Strength of SCC 5 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7800

28

225

35

15.5

2

7850

28

225

33

14.6

3

7790

28

225

34

15.11

15.07

Table 5.11 Compressive Strength of SCC 5 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Load 'P' In Ton

2

Cm

Compressive

Average

Strength

Compressive

2

N/mm

Strength N/mm2

In 'gm' 1

8050

28

225

70

31.11

2

8000

28

225

72

32.0

3

7900

28

225

68

30.2

31.10

Table 5.12 Compressive Strength of SCC 6 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7800

7

225

48

20.93

2

7850

7

225

45

19.62

3

7790

7

225

46

20.06

Ghousia College of Engineering, Ramanagaram

20.20

Page 36

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.13 Compressive Strength of SCC 6 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

8050

28

225

84

37.33

2

8000

28

225

86

38.22

3

7900

28

225

82

36.44

37.33

Table 5.14 Compressive Strength of SCC 7 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Load 'P' In Ton

2

Cm

Compressive

Average

Strength

Compressive

2

N/mm

Strength N/mm2

In 'gm' 1

8000

7

225

48

21.33

2

8150

7

225

52

23.11

3

8170

7

225

51

22.67

22.37

Table 5.15 Compressive Strength of SCC 7 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

8050

28

225

87

38.67

2

8000

28

225

88

39.11

3

7900

28

225

90

40.0

Ghousia College of Engineering, Ramanagaram

39.26

Page 37

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.16 Compressive Strength of SCC 8 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressive

Average

Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7800

7

225

51

22.6

2

7850

7

225

54

24.0

3

7790

7

225

54

24.0

23.53

Table 5.17 Compressive Strength of SCC 8 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Load 'P'

2

In Ton

Cm

Compressive

Average

Strength

Compressive

2

N/mm

Strength N/mm2

In 'gm' 1

8050

28

225

90

40.0

2

8000

28

225

91

40.44

3

7900

28

225

89

39.56

40.0

Table 5.18 Compressive Strength of SCC 9 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressi

Average

ve Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

7800

7

225

49

21.78

2

7850

7

225

49

21.78

3

7790

7

225

46

20.44

Ghousia College of Engineering, Ramanagaram

21.33

Page 38

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.19 Compressive Strength of SCC 9 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressi

Average

ve Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

8050

28

225

88

39.11

2

8000

28

225

87

38.67

3

7900

28

225

91

40.0

39.26

Table 5.20 Compressive Strength of SCC 10 (7 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

2

Load 'P' In Ton

Cm

Compressi

Average

ve Strength

Compressive

2

N/mm

Strength N/mm2

In 'gm' 1

7800

7

225

49

21.78

2

7850

7

225

46

20.44

3

7790

7

225

46

20.44

20.89

Table 5.21 Compressive Strength of SCC 10 (28 Days) No.

Weight

Age of

Area of

of

of

Cube In

Cube

Cube

Cube

Days

Cm2

Load 'P' In Ton

Compressi

Average

ve Strength

Compressive

N/mm2

Strength N/mm2

In 'gm' 1

8050

28

225

85

37.78

2

8000

28

225

85

37.78

3

7900

28

225

88

39.11

Ghousia College of Engineering, Ramanagaram

38.22

Page 39

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.22 Avg. Compressive Strength on 7 and 28 Days SI.

Mix Designation

No

Compressive Strength (N/mm2) 7 Days

28 Days

1

SCC 1

14.2

30.03

2

SCC 2

16.83

32.50

3

SCC 3

17.77

33.02

4

SCC 4

16.14

32.14

5

SCC 5

15.07

31.10

6

SCC 6

20.20

37.33

7

SCC 7

22.37

39.26

8

SCC 8

23.53

40.00

9

SCC 9

21.3

39.26

10

SCC 10

20.89

38.20

Graph 5.1 Comparison of Compressive Strength for M20 Grade

compressive strength(N/mm2)

35 30 25 20 7 days 15

28 days

10 5 0 SCC 1

SCC 2

SCC 3

Ghousia College of Engineering, Ramanagaram

SCC 4

SCC 5

Page 40

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Graph 5.2 Comparison of Compressive Strength for M30 Grade

compressive strength(N/mm2)

45 40 35 30 25 20

7 days

15

28 days

10 5

0 SCC 6

SCC 7

SCC 8

SCC 9

SCC 10

Graph 5.3 Comparison of M20 Grade and M30 Grade of SCC for 7 Days Strength

Compressive Strength (N/mm2)

45 40 35 30 25 20

M30 grade M20 Grade

15 10 5 0 0.00%

0.05%

0.10%

0.15%

0.20%

% of Glass Fibre

Ghousia College of Engineering, Ramanagaram

Page 41

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Graph 5.4 Comparison of M20 Grade and M30 Grade of SCC for 28 Days Strength

Compressive Strength (N/mm2)

45 40 35 30

25 20 M20 Grade 15

M30 Grade

10 5 0 0.00%

0.05%

0.10%

0.15%

0.20%

% of Glass Fibre

5.5.2 Test for Split Tensile Strength The split tensile strength of concrete was obtained indirectly by subjecting concrete cylinders to the action of a compressive force along two opposite generators. In this investigation self compacting cylinder of 150mm dia×300mm length were used for testing the compressive strength The split tensile strength is calculated by using the formula

σsp=

𝟐𝐏 𝛑𝐃𝐋

where, P=Load in KN D= diameter of cylinder L=length of cylinder

The test results are tabulated in Table 5.23 to Table 5.32 below.

Ghousia College of Engineering, Ramanagaram

Page 42

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.23 Split Tensile Strength of SCC 1 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.450

2

12.600

3

12.200

28

300mm dia

3.93

×150mm

3.54

length

3.65

3.7

Table 5.24 Split Tensile Strength of SCC 2 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.300

2

12.600

3

12.250

28

300mm dia

3.9

×150mm

4.8

length

4.6

4.43

Table 5.25 Split Tensile Strength of SCC 3 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.450

2

12.600

3

12.200

28

300mm dia

4.5

×150mm

5.0

length

4.75

4.75

Table 5.26 Split Tensile Strength of SCC 4 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.500

2

12.800

3

12.300

28

300mm dia

3.9

×150mm

4.1

length

3.4

Ghousia College of Engineering, Ramanagaram

3.8

Page 43

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.27 Split Tensile Strength of SCC 5 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.300

2

12.450

3

12.700

28

300mm dia

4.0

×150mm

3.50

length

3.60

3.7

Table 5.28 Split Tensile Strength of SCC 6 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.500

2

12.700

3

12.650

28

300mm dia

4.5

×150mm

4.6

length

4.5

4.53

Table 5.29 Split Tensile Strength of SCC 7 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.450

2

12.600

3

12.200

28

300mm dia

4.70

×150mm

4.35

length

4.80

4.62

Table 5.30 Split Tensile Strength of SCC 8 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.700

2

12.600

3

12.500

28

300mm dia

4.50

×150mm

4.90

length

4.70

Ghousia College of Engineering, Ramanagaram

4.70

Page 44

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.31 Split Tensile Strength of SCC 9 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.450

2

12.600

3

12.200

28

300mm dia

4.60

×150mm

4.35

length

4.50

4.68

Table 5.32 Split Tensile Strength of SCC 10 Sl.

Weight of

Age of

Size of

Split Tensile

Avg. Split

No

Cylinder (kg)

Cylinder

Cylinder

Strength

Tensile Strength

(N/mm2)

(N/mm2)

in Days 1

12.750

2

12.800

3

12.900

28

300mm dia

4.45

×150mm

4.75

length

4.60

4.6

Graph 5.5 Comparison of Split Tensile Strength for M20 Grade 5

Split Tensile Strength(N/mm2)

4.5 4 3.5 3 2.5 28 days 2 1.5 1 0.5 0 SCC 1

SCC 2

SCC 3

Ghousia College of Engineering, Ramanagaram

SCC 4

SCC 5

Page 45

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Graph 5.6 Comparison of Split Tensile Strength for M30 Grade 4.75

Split Tensile Strength (N/mm2)

4.7 4.65 4.6 28 days

4.55 4.5 4.45 4.4 SCC 6

SCC 7

SCC 8

SCC 9

SCC 10

Graph 5.7 Comparison of Split Tensile Strength of M20 and M30 Grade

Split Tensile Strength(N/mm2)

5 4.5 4 3.5 3 2.5 2

M20 Grade

1.5

M30 Grade

1 0.5 0 0.00%

0.05%

0.10%

0.15%

0.20%

% of Glass Fibre

Ghousia College of Engineering, Ramanagaram

Page 46

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

5.5.3 Test for Flexural Strength The flexure test is done on a prism of 100mm×100mm×500mm size prism loaded at the centre of the span. The maximum tensile strength is called modulus of rupture and is computed from the formula Flexural strength =

𝐏𝐋 𝐛𝐝𝟐

Where, b= measured width in mm d=measured depth in mm l=length in mm P=maximum load in KN The test result has been calculated and is tabulated in Table 5.33 to Table 5.42 below Table 5.33 Flexural Strength of SCC 1 SI.

Age of Prism

Crushing Load

Flexural

Avg. Flexural

No

in Days

(Tons)

Strength(N/mm2)

Strength (N/Mm2)

1 2

28

3

4.4

2.2

4.5

2.25

4.9

2.45

2.3

Table 5.34 Flexural Strength of SCC 2 SI.

Age of Prism

Crushing Load

Flexural

Avg. Flexural

No

in Days

(Tons)

Strength(N/mm2)

Strength (N/Mm2)

1 2 3

28

4.8

2.4

5.2

2.6

4.6

2.3

Ghousia College of Engineering, Ramanagaram

2.43

Page 47

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.35 Flexural Strength of SCC 3 SI. No

Age of Prism in Days

Crushing Load (Tons)

Flexural

Avg. Flexural 2)

Strength(N/mm

Strength (N/Mm2)

1 2

28

3

5.8

2.9

6.9

3.45

6.3

3.15

3.17

Table 5.36 Flexural Strength of SCC 4 SI.

Age of Prism

Crushing Load

Flexural

Avg. Flexural

No

in Days

(Tons)

Strength(N/mm2)

Strength (N/Mm2)

1 2

28

3

6.60

3.3

5.58

2.79

6.28

3.14

3.08

Table 5.37 Flexural Strength of SCC 5 SI.

Age of Prism

Crushing Load

Flexural

Avg. Flexural

No

in Days

(Tons)

Strength(N/mm2)

Strength (N/Mm2)

1 2

28

3

5.70

2.85

5.80

2.90

6.10

3.05

2.93

Table 5.38 Flexural Strength of SCC 6 SI. No

Age of Prism in Days

Crushing Load (Tons)

Flexural

Avg. Flexural 2)

Strength(N/mm

Strength (N/Mm2)

1 2 3

28

7.90

3.95

7.60

3.8

7.86

3.93

Ghousia College of Engineering, Ramanagaram

3.89

Page 48

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Table 5.39 Flexural Strength of SCC 7 SI. No

Age of Prism in Days

Crushing Load (Tons)

Flexural

Avg. Flexural 2)

Strength(N/mm

Strength (N/Mm2)

1 2

28

3

7.82

3.91

8.20

4.10

8.30

4.15

4.05

Table 5.40 Flexural Strength of SCC 8 SI.

Age of Prism

Crushing Load

Flexural

Avg. Flexural

No

in Days

(Tons)

Strength(N/mm2)

Strength (N/Mm2)

1 2

28

3

8.52

4.26

9.56

4.78

9.20

4.60

4.54

Table 5.41 Flexural Strength of SCC 9 SI.

Age of Prism

Crushing Load

Flexural

Avg. Flexural

No

in Days

(Tons)

Strength(N/mm2)

Strength (N/Mm2)

1 2

28

3

7.60

3.80

8.00

4.00

8.10

4.05

3.95

Table 5.42 Flexural Strength of SCC 10 SI. No

Age of Prism in Days

Crushing Load (Tons)

Flexural

Avg. Flexural 2)

Strength(N/mm

Strength (N/Mm2)

1 2 3

28

8.30

4.13

7.96

3.98

7.92

3.96

Ghousia College of Engineering, Ramanagaram

4.02

Page 49

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Graph 5.8 Comparison of Flexural Strength for M20 Grade 3.5

Flexural Strength(N/mm2)

3 2.5 2 28 days

1.5 1

0.5 0 SCC 1

SCC 2

SCC 3

SCC 4

SCC 5

Graph 5.9 Comparison of Flexural Strength for M30 Grade

Flexural Strength(N/mm2)

4.6 4.4 4.2 4 28 days

3.8 3.6 3.4 SCC 6

SCC 7

SCC 8

Ghousia College of Engineering, Ramanagaram

SCC 9

SCC 10

Page 50

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE Graph 5.10 Comparison of Flexural Strength of M20 and M30 Grade 5

Flexural strength (N/mm2)

4.5 4 3.5 3 2.5 2

M20 Grade

1.5

M30 Grade

1 0.5 0 0.00%

0.05%

0.10%

0.15%

0.20%

% of Glass Fibre

Ghousia College of Engineering, Ramanagaram

Page 51

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 6

DISCUSSIONS 6.1 Observations A close study on the have been done based on the experimental work carried out. Following points were noted on the basis of the results obtained. 1.

The slump flow decreases with increase in glass fibre content

2.

The load carrying capacity of GFRSCC is more than that of SCC.

3.

GFRSCC shows a considerable increase in the compressive strength than that of SCC.

4.

The split tensile strength of GFRSCC is more than that of SCC.

5.

The flexural strength of GFRSCC is higher than that of SCC.

6.2 Conclusion The present study has shown that incorporation of glass fibre in SCC has a considerable increase in compressive, flexural and split tensile strength. 1. SCC and GFRSCC have a slump in the range of 650-800mm and a flow time ranging from 8-10sec and the slump flow decreases with increase in glass fibre for both M20 and M30 grades. 2. The specimen with 0.05%, 0.1%, 0.15% and 0.2% of glass fibre shows an increase of compressive strength by 8.2%, 9.2%, 7.02% and 3.5% respectively than the SCC without fibre for the first mix proportion. 3. The specimen with 0.05%, 0.1%, 0.15% and 0.2% of glass fibre has in increase compressive strength of 5.1%, 7.1%, 5% and 2.3% respectively than the SCC without fibre for the second mix proportion. 4. The SCC developed split tensile strengths ranging from 3.7MPa to 4.75 MPa for M20 grade and from 4.53 MPa to 4.8 MPa for M30 grade 5. GFRSCC with 0.1% glass fibre showed substantial increase in the flexural strength than the other specimens.

Ghousia College of Engineering, Ramanagaram

Page 52

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE SFRSCC mixes show higher compressive, split tensile and flexural strength rather than normal compacting concrete. Use of fly ash increased the workability characteristics of SCC mixtures. And the GFRSCC with 0.1% glass fibre showed considerable increase in considerable strength, tensile strength and flexure.

Ghousia College of Engineering, Ramanagaram

Page 53

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 7

SCOPE FOR FURTHER WORKS 1. Further studies can be done using different mineral admixtures like GGBS, rice husk ash, etc. as cement replacement material. 2. Studies can be done by varying the percentage of fly ash used as cement replacement material. 3. Studies can be done with fibres of different aspect ratio.

Ghousia College of Engineering, Ramanagaram

Page 54

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE

Chapter 8

REFERENCES 1. T. Suresh Babu, M.V. Seshagiri Raoband D. Rama Seshu, “Mechanical Properties And Stress- Strain Behaviour Of Self Compacting Concrete With And Without Glass Fibres”, Asian Journal Of Civil Engineering (Building And Housing) Vol. 9, No. 5 (2008) Pages 457-472. 2. Prajapati Krishnapal, Chandak Rajeev and Dubey Sanjay Kumar, “Development and Properties of Self Compacting Concrete Mixed with Fly Ash”, Research Journal of Engineering Sciences ISSN 2278 – 9472,Vol. 1(3), 11-14, Sept. (2012). 3. P Srinivasa Rao, G K Vishwanadh, P Sravana, T Seshadri Sekhar, “Flexural Behaviour Of Reinforced Concrete Beams Using Self Compacting Concrete”, 34th Conference on Our World In Concrete & Structures: 16 – 18 August 2009, Singapore. 4. B. Krishna Rao, Professor V. Ravindra, “Steel Fibre Reinforced Self Compacting Concrete Incorporating Class F Fly Ash”, International Journal of Engineering Science and Technology, Vol. 2(9), 2010, 4936-4943. 5. M Chandrasekhar, M V Seshagiri , B. Krishna Rao, Maganti Janardhana, “Studies on stress-strain behaviour of SFRSCC and GFRSCC under axial Compression”, International Journal of Earth Sciences and Engineering ISSN 0974-5904, Volume 04, No 06 SPL, October 2011, pp. 855-858. 6. J. Guru Jawahar, C. Sashidhar, I.V. Ramana Reddy And J. Annie Peter, “A Simple Tool For Self Compacting Concrete Mix Design”, International Journal of Advances In Engineering & Technology, May 2012, ISSN: 2231-1963, 550 Vol. 7. Hajime Okamura and Masahiro Ouchi (2003), “Self-Compacting Concrete “, Journal of Advanced Concrete Technology, Japan Concrete Institute, Vol. 1, pp. 5-15. 8. M.S. Shetty, “Concrete Technology-Theory and Practice, S. Chand & Company Ltd. New Delhi – 2005, Chapter - 12. 9. S.K. Duggal, Building Materials, New Age Publishers, 2nd edition. 10. IS: 456-2000 , Indian Standard Plain And Reinforced Concrete Code Of Practice. 11. IS: 10262-1982, Indian Standard Concrete Mix Proportioning- Guidelines. Ghousia College of Engineering, Ramanagaram

Page 55

A STUDY ON SELF COMPACTING CONCRETE USING FLY ASH AND GLASS FIBRE 12. IS: 3812-2003, Specifications for Pulverized fuel ash, Bureau of Indian Standards, New Delhi, India (2003) 13. Specification and Guidelines for Self-Compacting Concrete” EFNARC, February 2002. 14. IS: 12269 -1987 Indian Standard Specification for 53 Grade Ordinary Portland Cement. 15. IS: 2386-1975 Indian Standard Methods of Test for Aggregates For Concrete.

Ghousia College of Engineering, Ramanagaram

Page 56