A Study on Concrete with Partial Replacement of Lime Powder and GGBS in Cement

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International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 7, Issue 10, October 2017)

109

A Study on Concrete with Partial Replacement of Lime Powder

and GGBS in Cement

V. Mani

1

,

S. Shameem Banu

2

M.Tech, Structural Engineering, Department of Civil Engineering, JNTU Kakinada, India

Assistant Professor Dept of Civil Engg UCEK JNTU Kakinada, India

Abstract—The aim of this paper is to evaluate the mechanical and durability properties of concrete by replacing cement partially with Lime Powder and GGBS. A total of 5 concrete mixes of M25 grade of concrete were cast, in which Lime powder content was fixed to 10% and GGBS was increased by 10% for each mix. These specimens were tested for Compressive strength, Split Tensile strength & Flexural strength at the age of 7days, 28 days & 56 days. To determine Stress-Strain behavior of concrete Modulus of elasticity test was done at the age of 28 days. Durability tests were also conducted for 28 days using sea water. Durability characteristics such as Acid Durability Factor, Loss of strength & Loss of weight are analyzed and compared with the convention mix.

Keywords—Compressive Strength, Flexural Strength, GGBS, Lime Powder, Stress-Strain Behaviour, Tensile Strength.

I. INTRODUCTION

Cement is an extremely important construction material used for housing and infrastructure development and a key to economic growth. Despite its popularity and profitability, the cement industry faces many challenges due to environmental concerns and sustainability issues. Utilization of industrial waste products in the construction industry has been the focus of research for economical and

environmental reasons. The solution to reduce

environmental problems and cost by the utilization of industrial by-products or natural pozzolans such as GGBFS, fly ash, lime powder, silica fume etc in producing concrete.

Nowadays limestone powder and GGBS are widely used in concrete as blended materials in cement. The replacement of Portland cement by limestone powder and GGBS can lower the cost and enhance the greenness of concrete, since the production of these two materials needs less energy and causes less CO2 emission.

II. MATERIALS AND THEIR PROPERTIES

A. Cement

The type of cement used in this investigation is Ordinary Portland cement of 53 grade having Specific gravity of 3.1, Fineness of 4%, Consistency of 29%, Initil and Final setting time of 85 and 190 min respectively.

B. Fine Aggregate

The sand obtained for the investigation is from nearby river course and confining to Zone-III having Specific gravity 2.52, Fineness modulus of 2.4, Bulk density (compacted) of 16.5 KN/m3.

C. Coarse Aggregate

The coarse aggregate used in this investigation are obtained from local crushing unit. The maximum size of aggregate used in this investigation is 20 mm. The Specific gravity is 2.75, Fineness modulus is 8.01, Bulk density (compacted) is 16.1 KN/ m3.

D. Lime Powder

Limestone is a naturally occurring Calcareous

sedimentary rocks produced at the bottom of the seas and lakes due to the accumulation of shells and is composed largely of minerals such as calcite and aragonite. The compressive strength of limestone is in the range of about 60-170N/mm2 and the water absorption of the limestone is less than 1% and Specific gravity of 2.65.

E. GGBS

Ground Granulated Blast furnace Slag (GGBS) is a byproduct from the blast furnaces used to make iron. Ground granulated blast furnace slag is one of the pozollonic material, when mixed with Portland clinker and water, produce C–S–H similar to that generated from the hydration of calcium silicate of clinker. This reaction is slow compared with that of the Portland cement, leading to a lower strength at early ages and similar or higher values at later ages.

III. MIX DESIGN

There are certain standard for mix design proposed by Indian Standards. The code for mix design is IS 10269: 2009 and IS 456:2000. These two codes have given minimum specifications for the design code.

A. Target Strength For Mix Proportion f‘ck =fck+1.65*S

=25+1.65*4

=31.6 N/mm2

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From Table 1, standard deviation(S) = 4N/mm2.

Target strength = 31.6 N/mm2.

B. Selection Of Water-Cement Ratio

From table 5 of IS 456-2000, maximum water cement ratio=0.5

Adopt w/c = 0.48

C. Selection Of Water Content

From table 2, maximum water content = 186 liters (for 25-50mm slump range)

Water content = 186 liters

D. Calculation Of Cement Content

Water-Cement ratio = 0.48 Cement Content = 186/0.48

= 387.45kg/m3.

From Table 5 of IS456-2000 minimum cement content 320 kg/m3

387.45kg/m3>320kg/m3

E. Proportion Of Volume Of Coarse Aggregate And Fine Aggregate Content

From Table 3 of IS: 10262-2009,

Volume of coarse aggregate for w/c of 0.48 = 0.644. Volume of fine aggregate = 0.356.

F. Mix Calculations

a. Volume of concrete = 1m3

b. Volume of cement = (Mass of cement/Specific Gravity of cement)*(1/1000)

= (387.45/3.1)*(1/1000) = 0.124m3

c. Volume of water = (Mass of Water/ Specific Gravity of water)*(1/1000)

= (186/1)*(1/1000) = 0.186m3

d.Volume of all in aggregates= a-(b+c) = 1-(0.124+0.186)

=0.689m3

e.Mass of coarse aggregate = d x volume of CA x S.G of CAx 1000

= 0.689 x 0.644 x 2.75 x 1000 = 1220.219m3

f.Mass of fine aggregate = d x volume of FA x S.G of FA

x1000

= 0.689 x 0.356 x 2.52 x 1000 = 618.12m3

G. Mix Proportions For Trail Cement = 387.45kg/m3 Water = 186 lt

Fine aggregate = 618.12kg Coarse aggregate = 1200.22kg

Water cement ratio = 0.48 H. Ratio Of Mix Proportion

Cement: FA: CA = 387.45: 618.12: 1200.22 =1: 1.59: 3.14

IV. EXPERIMENTAL INVESTIGATION

It was proposed to investigate the properties of concrete, cast with partial replacement of cement with lime powder and GGBFS.

The replacement levels are as follows: 0% LP & 0% GGBS

10% LP & 0% GGBS 10% LP & 10% GGBS 10% LP & 20% GGBS 10% LP & 30% GGBS.

Lime powder content replacement was fixed to 10 % of cement content and GGBS content varies in 0%, 10 %, 20% and 30%.

A. Tests On Fresh Concrete 1) Slump Cone Test:

To determine the workability of concrete slump cone test was conducted, the dimensions of the slump cone are as follows:

Top diameter 10cm Bottom diameter 20cm Height of the cone 30cm

B. Tests On Hardened Concrete

1) Compressive strength:

Compression test was conducted on

150mm×150mm×150mm cubes. Concrete specimens were removed from curing tank and cleaned. In the testing machine, the cube is placed with the cast faces at right angles to that of compressive faces, then load is applied at a constant rate of 1.4 kg/cm2/minute up to failure and the ultimate load is noted. The load is increased until the specimen fails and the maximum load is recorded. The compression tests were carried out at 7, 28, 56 days. For strength computation, the average load of three specimens is considered for each mix. The average of three specimens was reported as the cube compressive of strength.

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2) Split tensile strength test:

The cylinder specimen is of the size 150 mm diameters and 300mm length. The test is carried out by placing a cylindrical specimen horizontally between the loading surfaces of compression testing machine and the load is applied until failure of cylinder, along its longitudinal direction.

The cylinder specimens are tested at 7 days, 28 days and 56 days. The average of three specimens was reported as the split tensile strength. Split tensile strength = (2×P)/(π×D×L)

Where P = compressive load on the cylinder. L=length of the cylinder.

D=diameter of the cylinder.

3) Flexural Strength Test:

In the flexural strength test theoretical maximum tensile stress reached at the bottom fibres of the test beam is known as the modulus of rupture. When concrete is subjected to bending stress, compressive as well as tensile stresses are developed at top and bottom fibres respectively. The strength shown by the concrete against bending is known as flexural strength. The standard size of specimen is 150mm×150mm×700mm.

The flexural strength of the specimen is expressed as the modulus of rupture ‗fb‘ which, if ‗a‘ equals the distance

between the line of fracture and the nearest support measured on the centre line of the tensile side of the specimen, in cm, is calculated to the nearest 0.05Mpa as follows:

= PL/bd2

f = M/ Z = (PL/6)⁄(bd2_/6)

When ‗a‘ greater than 20 cm for 15cm specimen = 3Pa/ bd2

when ‗a‘ is less than 20cm but greater than 17cm for 15cm specimen or less than13.30 But greater than 11.00cm for a 10cm specimen .

Where, P = ultimate load in N L = span of the beam in mm b = width of the specimen in mm d = depth of the specimen in m

The flexural beam specimens are tested at 7 days, 28 days and 56 days. The average of three specimens was reported as the flexural tensile strength.

4) Durability test methods:

The durability of concrete is defined as its ability to resist weathering action, chemical attack, abrasion, or any other process of deterioration. Durable concrete will retain its original form, quality, and serviceability when exposed to environment.

Sea water curing: On an average, seawater in the world's oceans has a salinity of approximately 3.5%, or 35 parts per thousand. This means that for every 1 litre (1000 ml) of seawater there are 35 grams of salts (mostly, but not entirely, sodium chloride) dissolved in it. Although a vast majority of seawater is found in oceans with salinity around 3.5%, seawater is not uniformly saline throughout the world.

In this investigation the cubes were cast and cured in sea water for the age of 28 days. Average % decrease in weight and average % decrease in compressive strength were evaluated.

The chemical composition of the Sea water is tabulated as below

Table I Properties Of Sea Water

S. No Composition Concentration(mg/l)

1 PH 8.30

2 Chloride content 19.34

3 Sulphate content 2701

5)Modulus of elasticity test (Stress- strain behaviour of concrete):

A typical relationship between stress and strain for normal strength concrete is discussed. For calculating the modulus of elasticity of concrete, tests were conducted on 150mm x 300 mm cylinder specimens on Compression testing machine of capacity 200T. The test was performed as per Indian standard specifications BIS: 516-1959. Compressometer used for determining the change in length of concrete specimen on compressive loading. The Compressometer consist of two frames for clamping to the specimens by means of tightening screws. Two spacers hold the two frames in positions. The gauge length is 150mm. The readings from the dial gauge are noted, the readings thus obtained with respect to load are tabulated and a graph is plotted from the obtained stresses and strains.

V. RESULTS AD DISCUSSION

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[image:4.612.328.560.137.281.2]

A.Tests On Fresh Concrete 1) Slump Cone Test Results:

Table II Slump Cone Test Results

% Rep. of % Rep. Slump

S.No Mix Lime Of

value(mm) powder GGBS

1 M1 0 0 63

2 M2 10 0 55

3 M3 10 10 48

4 M4 10 20 45

5 M5 10 30 42

Graph I Slump Vs % Replacement of cement

B.Tests On Hardened Concrete 1) Compressive Strength Test Results:

In this test cubes of standard size 150x150x150 mm3 were cast and the maximum load at failure was calculated using Compressive testing machine

Table III

Compressive Strength Test Results

S.NO %Rep. Of Compressive Strength in N/mm

2

cement 7 days 28 days 56 days

1 0 24.16 32.10 34.20

2 10 25.07 31.70 32.20

3 20 24.56 37.93 40.4

4 30 25.14 39.67 42.30

5 40 21.94 37.20 39.82

Graph II Compressive Strength Vs % Replacement of cement

1) Split Tensile Strength Test Results:

[image:4.612.44.297.162.367.2]

In this test cylinders of standard dimensions of diameter 150mm and height of 300 mm were cast and the maximum load at failure was calculated.

Table IV

Split Tensile Strength Vs % Replacement Of Cement

% Rep. Split Tensile Strength (N/mm2)

S.No Of

7 days 28 days 56 days Cement

1 0 1.40 1.94 2.12

2 10 1.60 1.92 1.99

3 20 1.48 2.02 2.22

4 30 1.62 2.22 2.32

5 40 1.30 1.55 1.64

[image:4.612.317.572.373.595.2]

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3) Flexural Strength Test Results:

[image:5.612.44.300.198.445.2]

In this test prisms of standard dimensions 150x150x700 mm3 were cast and the maximum load at failure was calculated using flexural testing machine.

Table V

Flexural Strength Test Results

% Rep. Flexural Strength (N/mm2)

S.No Of

7 days 28 days 56 days Cement

1 0 2.7 3.42 4.21

2 10 3.0 3.37 3.49

3 20 2.95 3.56 4.56

4 30 3.14 4.25 5.32

5 40 3.01 3.87 3.94

Graph IV Flexural Strength Vs % Replacement of cement

4) Durability Test:

[image:5.612.320.577.270.542.2]

In the investigation cubes of standard size 150x150x150 mm3 were cast and cured in sea water for 28 days after 28 days of normal curing and the Weight and compressive strength is compared with cubes that are cured in normal water.

Table VI

Comparison Of Weight Before And After Placing In Sea Water

Weight

Weight After

% Rep. Before % Loss

Curing in

S.No Of Placing in Of

Sea Water

Cement Sea Weight

(Kg) Water(Kg)

1 0 8.96 8.94 0.223

2 10 8.85 8.83 0.225

3 20 8.68 8.665 0.17

4 30 8.45 8.44 0.11

5 40 8.2 8.17 0.36

Graph V % Weight Loss Vs % Replacement of cement

Table VI

Comparison Of Compressive Strength

Compressive Compressive

% Rep. Strength Strength % Loss

S.No Of Before After Of

Cement Placing in Curing in Strength Sea Water Sea Water

1 0 32.1 31.26 2.61

2 10 31.4 30.28 3.56

3 20 37.93 36.54 3.66

4 30 39.67 38.87 2.02

5 40 37.2 33.14 10.1

Graph VI % Strength Loss Vs % Replacement of cement

5)Modulus Of Elasticity Test(Stress-Strain Behaviour Of Concrete):

[image:5.612.319.567.550.705.2]

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Theoretical Ec = 25000N/mm2

From the readings, the following were observed. Peak load = 515.2KN

Peak stress = 29.1MPa

Modulus of Elasticity = 23.1GPa.

V. CONCLUSION

 Workability Decreases as the percentage replacement of cement increases.

 Replacement of 30% cement by 10% Lime powder and

20% GGBS gives the optimum value for compressive

strength, split tensile strength and flexural strength.  From above results and discussions it was concluded that

the material can be replaced up to 30% in cement,

compared to normal concrete strength.

 test, secant modulus

calculated was 20GPa.

 After immersion in sea water for 28 days, the

lower for 30% replacement in cement.

 The acid durability factor for combined mixes is less compared to conventional mix for 28 days of immersion.

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Fume & Ground Granulated Blast Furnace Slag as Cement Replacement in Fiber Reinforced Concrete‖ IRJET- International Research Journal of Engineering and Technology| Vol. 2 Issue 07, ( Oct-2015)

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