strength behaviour of self curing fly ash concrete using · pdf filestrength behaviour of self...

International Journal of Engineering Trends and Technology (IJETT) – Volume 38 Number 8- August 2016

ISSN: 2231-5381 http://www.ijettjournal.org Page 420

Strength Behaviour of Self Curing Fly Ash Concrete using Steel Fibers and Its Analysis

using ANSYS Cyril Cyriac

Department of Civil Engineering, St Joseph’s College of Engineering and Technology Palai, Kerala, India

Abstract Self curing and internal curing is a technique that can be used to provide additional moisture in concrete for more effective hydration of cement and reduced self-desiccation Concrete usage around the world is second only to water. Ordinary Portland cement (OPC) is conventionally used as the primary binder to produce concrete. The environmental issues associated with the production of OPC are well known. The abundant availability of fly ash worldwide creates opportunity to utilize this by-product of burning coal, as a substitute for OPC to manufacture cement products. Addition of steel fiber has a significant role in increasing the tensile and compressive strength of concrete Keywords — Self curing, fly ash, steel fiber.

I. INTRODUCTION The advances in construction industry have

contributed tremendously for the new developments in construction chemicals. The use of various chemicals in concrete alters the properties of strength and durability. A durable concrete is one that performs satisfactorily in the working environment during its anticipated exposure conditions during service. Due to the vast construction activities different grades of concrete with natural and artificial ingridients are in use. It is observed during construction even though supervision is given importance proper care is not taken in the curing and other operations. As an alternative to water curing, different other methods are also available including membrane curing, polymer curing etc. Curing is the process of controlling the rate and extent of moisture loss from concrete during cement hydration. By proper curing only we can attain desirable strength properties. In practical good curing is not always possible, while poor curing process will affect the strength properties, self-curing methods are developed. By adding self-curing agents an internal water reservoir is created in the fresh concrete. Once the initial free water has been consumed, the water absorbed by the SAP will be gradually released to maximize the heat of hydration

II. SCOPE AND OBJECTIVES The aim of this research is to evaluate the effects of self-curing agents such as pre-soaked lightweight

aggregate and polyethylene-glycol with different ratios on the physical properties for concretes.The results should help explain the effect of self-curing agents on the physical properties of concrete. Also,the results provide additional data to determine self-curing agent content for optimization of the physical properties of concrete. Objecives of project are as follows

To analyse the properties of self curing fly ash concrete

To check the strength properties when steel fibers are added to flyash concrete

To check out the properties of concrete with different additions

To analyse the behavior of self curing fly ash concrete with the help of ANSYS software

III. LITERATURE REVIEW Karthik R and Jayajoth P et.al in,2015 reviewed

about self curingself compacting concrete has been studied using polyethylene glycol.The effect of compressive strength at 28 days was about 95% of strength achieved through immersion method of curing

Magda I Mousa et.al in 2014 studied the effect of two different curing-agents has been examined in order to compare them for optimizing the performance of concrete. The first used type is the Pre-soaked lightweight aggregate (leca) with different ratios; 0.0%, 10%, 15% and 20% of volume of sand,and the second type is a chemical agent of polyethylene-glycol (Ch.)The results show that the use of self-curing agent (Ch.) in concrete effectively improves the physical properties compared with conventional concrete. Stella Evangeline et.al in 2014 analysed that some specific water-soluble chemicals such as Polyvinyl alcohol added during the mixing can reduce water evaporation from and within the set concrete, making it self-curing. . The Compressive and tensile strength of self-curing concrete for 7 and 28 days is found out and compared with conventional concrete of similar mix design



Dr.A.K Verma and Dr.D.R Bhatt et.al in 2013 studied about the variation in compressive strength of medium strength self compacted concrete with three different curing techniques. First batch was cured in a temperature controlled curing tank, where as the second batch was cured by application of external curing compounds. The third batch was cured by internal curing compounds. From the experiment it was found that the 28 day compressive strength of cubes cured by applying curing compounds was 95% of the compressive strength of cubes cured in the laboratory Khadake S.N et.al in 2012 conducted investigation on M25 grade concrete with water-cement ratio of 0.465 to study compressive strength,flexural strength of steel fiber reinforced concrete.Fibers with aspectratio 71 is used in the investigation.Result data have showed an increase in 7,28 and 45 day compressive strength.Fiber reinforced concrete (FRC) is mixtures of cement concrete containing short discrete, uniformly dispersed and randomly oriented suitable fibrous material which increases its structural integrity.

IV. METHODOLOGY Curing is the process of controlling the rate and extent of moisture loss from concrete during cement hydration. It may be either after it has been placed in position or during the manufacture of concrete products. Good curing is not practically possible in most of the cases. The Self-curing concrete means that no external curing required for concrete. Self-curing provides an internal water reservoir throughout the concrete, so that it is more readily available to maintain saturation of the cement paste during hydration, avoiding self-desiccation (in the paste) and reducing autogenous shrinkage. The grade of concrete selected was M30. Self-curing is done by Super Absorbent Polymer (SAP). The effect of variation in strength properties were studied for different dosage of self-curing agent (0.1% – 0.5% weight of cement) steel fiber (1%, 1.5%, 2%)and compared with fly ash concrete. By compression test optimum percentage of SAP is found as 0.3 and steel fiber is 1.5 A. Materials

1) Cement:Ordinary Portland cement of grade 53 (IS 8112:1989). The total quantity of cement required was approximately estimated, brought and stored in an air tight container.

2) Fine Aggregate:Locally available river bed sand having specific gravity 2.56 and fineness modulus of 2.532 was used.

3) Coarse Aggregate:Locally available crushed granite chips having specific gravity 2.74 was used. The particle size varies from 10 to 20mm was used.

4) Fly Ash:Fly Ash collected from Neyveli Lignite Corporation, Neyveli, Tamil Nadu confirms to IS: 3812-1981 is a Class C Fly Ash (High Calcium Fly

Ash). The properties of Fly Ash are having 2.41 and fineness of 1.24 M2/g.

5) Silica Fume

Silica fume obtained from Bss private limited, ernakulam, India. The properties of silica fume are specific gravity 2.20 and fineness 20000 M2/kg.

6) Water

Potable water available in the college campus was used for preparing concrete in the entire experimental investigation.

7) Fiber:Double end hooked steel fibers with an aspect ratio of 50 were used

8) Polyethylene Glycol:

Polyethylene glycol is a condensation polymer of ethylene oxide and water with the general formula H(OCH2CH2)nOH, where n is the average number of repeating ox ethylene groups typically from 4 to about 180. The abbreviation (PEG) is termed in combination with a numeric suffix which indicates the average molecular weights B. Mix design Grade of concrete- M30 Type of cement- OPC 53 grade Nominal size of aggregate- 20mm Exposure condition- Severe Specific Gravity of cement- 2.78 Specific Gravity of coarse aggregate -2.74 Specific Gravity of fine aggregate- 2.565 Water absorption of coarse aggregate- 0.507% Water absorption of fine aggregate-1.0101% Target Strength f’ck = fck + 1.65 s = 30 + 1.65 X 5 f’ck=38.25 N/mm2 Selection of Water Cement Ratio Maximum water cement ratio = .45 Water cement ratio selected =.43 .43<.45, hence Ok. Selection of Water Content Maximum water content for 20mm aggregate = 186 L. Estimated water content for 100mm slump = 186 + 6/100 X186 = 197 L Calculation of Cement Content Water cement ratio = .43 Cement content = 197/.4 =458.13 Kg/m3 Minimum cement content for severe exposure condition is 340Kg/m3. 458.13 Kg/m3 > 340 Kg/m3, thus Ok. Proportioning of Coarse Aggregate and Fine Aggregate For zone II fine aggregate the volume of coarse aggregate corresponding to .5 water cement ratio



is .62. Since, the present water cement ratio is .43 proportion of coarse aggregate is increased by .02. Corrected proportion of corrected coarse aggregate content = .634 Thus, proportion of fine aggregate content = 1-0.634 =0.366 Mix Calculation Volume of Concrete = 1m3. Volume of Cement = 458.13/ 2.798 X 1/1000 =0.163 m3. Volume of water = 197/1 X 1/1000 = 0.197 m3. Volume of all aggregate = 1-(0.163+0.197) =0.64 Volume of coarse aggregate = .64 X .634 X 2.741 X 1000 = 1111.78 Kg. Volume of fine aggregate = .64 X .366 X 2.565 X 1000 = 600.82 Correction for Water Absorption For coarse aggregate = (0.507/100) X 1094.81 = 5.63 Kg. For fine aggregate = (1.01/100) X 600.82 = 6.068 Kg. Corrected weight of coarse aggregate = 1106.15 Kg Corrected weight of fine aggregate = 594.75 Kg Thus the proportion is, 1:1.29: 2.41 The concrete mix was designed for M30 grade as per IS 10262-2009 and mix proportion arrived as 1: 1.269: 2.57 with w/c 0.42. Cement replacement of 40% with fly ash and 10%were prepared. The quantities of aggregates, water content, cement and the additives are M1- Conventional Concrete M2- 50% Cement + 40% Fly Ash + 10% Silica fume M3- Self-curing Fly Ash concrete (50% Cement + 40% Fly Ash + 10% Silica fume+ SAP) M4- 50% Cement + 40% Fly Ash + 10% Silica fume + SAP + 1% steel fiber M5- 50% Cement + 40% Fly Ash + 10% Silica fume + SAP + 1.5% steel fiber M6- 50% Cement + 40% Fly Ash + 10% Silica fume + SAP + 2% steel fiber C. Tests conducted 1) Slump Cone Test:Slump test is used to determine the workability of fresh concrete. Slump test as per IS: 1919 – 1959 is followed. The apparatus used for doing slump test are Slump cone and tamping rod. concrete, this is the utmost important which gives an idea about all the characteristics of concrete. By this single test one judge that whether Concreting has been done properly or not. For cube test two types of specimens either cubes of 15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the size of aggregate are used. For most of the works cubical moulds of size 15 cm x 15cm x 15 cm are commonly used.

3) Splitting Tensile Strength Test:The split tensile strength was determined by subjecting 100mm diameter x 200mm long cylinders to diametric compression so as to induce uniform lateral tension on the perpendicular plane. At the end of each age of the specimen, the test was conducted as per IS: 5816-1999. 4) Flexural Strength Test:The flexural strength tests were carried out on beam specimen of size 100 x 100 x 500mm under two standard point loading at the end of each age of the specimen, flexural testing was conducted under uniform rate of loading of 180kg/cm2/min. and the procedure was followed according to IS: 516-1959. 5) Modulus of Elasticity:Cylinders of 150mm diameter x 300mm long specimens were cast and tested at the age of 28days in a compression testing machine. Deformation was measured using 250mm gauge length compress meter fixed on the surface of the cylinder. Readings were taken at regular intervals of load increment

D. ANSYS ANSYS finite element analysis software enables engineers to perform the following tasks: •Build computer models or transfer CAD models of structures, products, components, or systems. •Apply operating loads or other design performance conditions. •Study physical responses, such as stress levels, temperature distributions, or electromagnetic fields. •Optimize a design early in the development process to reduce production costs. • Do prototype testing in environments where it otherwise would be undesirable or impossible (for example, biomedical applications).

The ANSYS program has a comprehensive graphical user interface (GUI) that gives users easy, interactive access to program functions, commands, documentation, and reference material. An intuitive menu system helps users navigate through the ANSYS program. Users can input data using a mouse, a keyboard, or a combination of both thickness of cover concrete provided for embedded peripheral rebars.

VI. RESULTS AND DISCUSSION Workability and strength properties of conventional concrete (M1), fly ash concrete (M2),self-curing fly ash concrete (M3), self- curing fly ash concrete with 1% steel fiber (M4),self- curing fly ash concrete with 1.5% steel fiber (M5), self- curing fly ash concrete with2% steel fiber (M6) were compared at the age of 7 and 28 days


ISSN: 2231-5381 http://www.ijettjournal.org 23

1) Compressive strength

Fig 1 compression testing apparatus This is the utmost important which gives an idea about all the characteristics of concrete. Compressive strength at 7 and 28days were obtained by applying load using compression testing machine..Compressive strength at 7 and 28days were obtained by applying load using compression testing machine VI. TABLE 1 Compressive strength of various mixes

05

10152025303540

M1 M2 M3 M4 M5 M6

7 day

28 day

Fig 1 Graph showing compressive strength of various mixes

2) Flexural strength The flexural strength tests were carried out on beam specimen of size 100 x 100 x 500mm under two standard point loading at the end of each age of the specimen, flexural testing was conducted under uniform rate of loading of 180kg/cm2/min. And the procedure was followed according to IS: 516-1959. VII. TABLE 2 Flexural strength of various mixes

Mix

7 day

strength

(N/mm²)

28 day

strength

(N/mm²)

M1 4.6 7.2

M2 3 4.9

M3 4.4 6.3

M4 4.2 6.5

M5 4.7 7.3

M6 3.9 6.2

0

2

4

6

8

M1 M2 M3 M4 M5 M6

7 day

28 day

Fig 2 Graph showing flexural strength of various mixes 3) Splitting Tensile Strength Test The split tensile strength was determined by subjecting 100mm diameter x 200mm long cylinders to diametric compression so as to induce uniform lateral tension on the perpendicular plane. VIII. TABLE 3 Splitting tensile strength of various mixes

Mix

7day

strength

(N/mm²)

28day

strength

(N/mm²)

M1 26.25 35.27

M2 22.37 34.17

M3 25.96 36.38

M4 25.01 36.59

M5 27.36 37.56

M6 24.56 34.87

Mix

7 day

strength

(N/mm²)

28 day

strength

(N/mm²)

M1 4.3 8.3

M2 3 6.2

M3 4.1 7.1

M4 4.2 8.2

M5 4.6 10.1

M6 4 8.5



0

5

10

15

20

M1 M2 M3 M4 M5 M6

28 day

7 day

Fig 3 Graph showing split tensile strength value of various mixes 4) Slump test Slump test is used to determine the workability of fresh concrete. Slump test as per IS: 1919 – 1959 is followed. The apparatus used for doing slump test are Slump cone and tamping rod. Slump depends on many factors like properties of concrete ingredients – aggregates etc. Also temperature has its effect on slump value IX. TABLE 4 Slump value of various mixes

Fig 4 Graph showing slump value of various mixes

5) Modulus of elasticity Cylinders of 150mm diameter x 300mm long specimens were cast and tested at the age of 28days in a compression testing machine. Deformation was measured using 250mm gauge length compress meter fixed on the surface of the cylinder. Readings were taken at regular intervals of load increment X. TABLE 5 Modulus of elasticity of various mixes

30

31

32

33

34

M1 M2 M3 M4 M5 M6

Modulus of elasticity

Fig 5 Graph showing modulus of elasticity of various

mixes

6) Analysis using ANSYS Analysis of a beam with size 100mm*100mm and 500mm was done.Following results were obtained after the analysis

Fig 6 Figure showing elemental result of beam

Mix Slump value(cm)

M1 8.8

M2 7.2

M3 11.4

M4 10.5

M5 9.6

M6 9.0

Mix Modulus of

elasticity(GPa)

M1 32.7

M2 31.1

M3 31.6

M4 32.0

M5 32.9

M6 31.1

0

5

10

15

M1 M2 M3 M4 M5 M6

Slump



Fig 7 figure showing displacement of beam

Fig 8 Figure showing nodal solution

Fig 9 figure showing the result when load of 10Kn/m is applied to the beam

VIII. CONCLUSIONS By the above testing results following conclusions are made:

Self-curing Fly ash Concrete (M3) gives high Compressive Strength, Tensile

Strength and Flexural Strength when compared to externally cured Fly ash Concrete.

When Steel Fiber is added to the Self-Curing Fly Ash Concrete the strength

Properties go on increasing for 1% and 1.5% addition.

When 2% Steel Fiber is added the Strength properties suddenly decreases.

All the Self-curing Fly Ash concrete mixes with steel fibers (M4, M5, M6) give high Strength compared to normal curing mix.

Addition of 1.5% Steel Fiber in Self-curing Fly Ash concrete gives high strength than conventional concrete.

As the fiber content increases it will result to difficulty in compaction due to balling of fibers.The slump value also decreased due to this above factor

REFERENCES [1] Alvaro Paul and Mauricio Lopez (2011), ‘ Assessing

Lightweight Aggregate Efficiency for Maximizing Internal Curing Performance’, ACI Materials Journal, volume 108.

[2] Ambily.P.S and Raja mane N.P,(2009)‘Self-Curing Concret an Introduction’,Concrete Composites Lab, Structural Engineering Research Centre, Chennai.

[3] Bart Craeye, Matthew Geirnaerta and Geert De Schutter, (2011), ‘Super absorbing polymers as an internal curing agent for mitigation of early-age cracking of high performance concrete bridge decks’ Construction and Building Materials

[4] Bentz. D.P,(2007), ‘Internal curing of high-performance blended cement mortars’, ACI materials Journal 104 (4),August 2007

[5] Lura.P, (2005) ‘Mixture proportioning for internalcuring’Concrete International Paper

[6] Daniel Cusson, and Ted Hoogeveen, (2008), “Internal curing of high performance concrete with pre-soaked fine light weight aggregate for prevention of autogenous shrinkage cracking”, Cement and Concrete Research 38.

[7] El-Dieb. A.S, (2006), self – curing concrete: Water retention,

hydration and moisture transport. Construction and Building

Materials, 21, 1282 –1287

[8] Dr. A.K. Verma2, Dr. D.R. Bhatt (2013)’Comparison Of Compressive Strength Of Medium Strength Self Compacted Concrete By Different CuringTechniques”International Journal of Engineering Trends and Technology (IJETT)– Volume4 ,Issue5- May 2013

[9] KhadakeS.N,Konapure C.G (2012),”An Investigation of Steel Fiber Reinforced Concrete with Fly Ash”,IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), Volume 4, Issue 5 ,Nov-Dec. 2012

[10] Yogananda N (2014),”Experimental investigatio on self-curing

self-compacting concrete by replacing natural sand by M sand and coarse aggreagate by light weight aggregate for M40 grade concrete”,International Journal of Scientific and Research Publications, Volume 4, Issue 8, August 2014

[11] Stella Evangeline (2014),”Self Curing Concrete and Its Inherentproperties”, Int. Journal of Engineering Research and Applications, Vol. 4, Issue 8, August 2014

[12] S.B. Kulkarni AVP, Clinton Pereira, Significance ofCuring of Concrete for Durability ofStructures, NBM Construction Information,August 2011

[13] Vijai K, R. Kumutha and B. G. Vishnuram"Effect of types of curing on strength ofgeopolymer concrete" International Journal of the Physical Sciences, Vol.5(9) , (2010)

[14] ASTM C452-02,Standard Test Method for Potential Expansion of Portland-Cement Mortar Exposed to Sulphate, ASTM International, West Conshohocken, PA, .

[15] IS: 383-1970. Specifications for Coarse and Fine Aggregates from Natural Sources forConcrete. Bureau of Indian Standards,New Delhi.

[16] IS: 456-2000. Plain and Reinforced Concrete. Code of Practice, BIS

[17] IS 516:1959, Tests for strength of concrete- Code of Practice. [18] IS 10262:2009, Concrete Mix Proportioning- Guidelines

strength behaviour of self curing fly ash concrete using · pdf filestrength behaviour of self...

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