Partially Replacement of Portland Cement with Rice Husk Ash in Concrete


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Partially Replacement of Portland Cement with Rice Husk Ash in Concrete

Krishan Murari

Assistant Professor, dept. of Civil Engineering Vivekananda Institute of Technology

Jaipur, India

Dr. Praveen Kumar Navin

Assistant Professor, dept. of Civil Engineering Vivekananda Institute of Technology

Jaipur, India

AbstractConcrete is a site made material unlike other materials of construction and as such can vary to a very great extent in its quality, properties and performance owing to the use of natural materials except cement. From materials of varying properties, to may concrete of stipulated qualities, an intimate knowledge of the inter-action of various ingredients that in to the making of concrete is required to be known both in the plastic condition and in the hardened condition. Rice husk is an agriculture by-product generated from peddy. Presently there are limited uses of rice husk and unused quantity is dumped unattended in the landfills, which create pollution in the environment. In this study, characterization of rice husk ash was carried out to evaluate its engineering properties. The cements were replaced partially by rice husk ash in two grades of concrete i.e. M20 by 0%,5% 10%,15% and 20%,rice husk ash, by weight. The slump, compressive strength and flexural strength tests were conducted and results were analyzed.

Keywords Component; formatting; style; styling; insert (key words)

  1. INTRODUCTION

    Rice husk can be burnt into ash that fulfills the physical characteristics and chemical composition of mineral admixtures. Pozzolanic activity of rice husk ash (RHA) depends on (i) silica content, (ii) silica crystallization phase, and (iii) size and surface area of ash particles. In addition, ash must contain only a small amount of carbon.The optimized RHA, by controlled burn and/or grinding, has been used as a pozzolanic material in cement and concrete. Using it provides several advantages, such as improved strength and durability properties, and environmental benefits related to the disposal of waste materials and to reduced carbon dioxide emissions.

  2. LITERATURE REVIEW

    Prasad et. al. [1] Investigated on Cement concrete which continues to be the pre-eminent construction materials for use in any type of civil engineering structure He concluded in his investigation the blended cements, particularly are better in Sodium Sulphate environment. The blended cement mixes show more deterioration in Magnesium Sulphate exposure in compared to plain cement mixes. The Magnesium Sulphate environment is more severe than Sodium Sulphate environment. The performance of low water/binder ratio mixes is inferior in Sulphate resistance. The little initial air curing of mixes is beneficial for Sulphate resistance. He also stated that the deterioration of cement mixes increases with increase in the concentration of Sulphate. The presence of Chloride ions with Sulphate ions reduces the rate of Sulphate attack on cement mixes. The deterioration rate of mixes due to

    Sulphate attack is higher at high temperature with alternate wetting and drying cycles. Rao et. al [2] investigated on M20 grade of concrete. The title of a study on use of rice husk ash in concrete. They have tested the following parameters in concrete- Compressive Strength Test, Flexural Strength Test for 3 days,7 days, 28 days and 56 days. They have prepared 5 mixes of concrete. In mixes they replaced cement by 5%, 7.5%, 10%, 12.5% and 15% of rice husk ash. The results of their research were-(i) Compressive strength is increased up to when amount of rice husk ash 12.5 %.( ii) Flexural strength is gradually decreased with increased amount of rice husk ash. Nair et.al [3] has investigated on M60 grade of concrete. The title of their experimental program is Mechanical Properties of Rice Husk Ash (RHA) High strength Concrete. They have tested the following mechanical properties of concrete- Workability Compressive Strength (cube), Flexural Strength, bond strength, modulus of elasticity, density and Split Tensile Strength and fresh concrete property workability. They have prepared mixes of concrete; In mixes they replaced cement by 0%, 5%, 15% and 25% rice husk ash in M60 grade concrete.

  3. MATERIAL AND METHOD

    1. Coarse Aggregate

      20mm and 10mm (as shown in fig. 1 and 2) nominal size of coarse aggregate is used for experiment. For gradation of coarse aggregate IS 383:1970[4] used. For obtained the mechanical property of coarse aggregate (Table 1) IS: 2386- 1963 Part- III [5] used.

      Fig. 1. Coarse Aggregates (20 mm)

      Fig. 2. Coarse Aggregates (10 mm)

      Table 1. Properties of Coarse Aggregates

      Property Test

      Coarse Aggregates

      20 mm

      10 mm

      Sp. Gravity (OD)

      2.66

      2.62

      Sp. Gravity (SSD)

      2.64

      2.64

      Sp. Gravity (Apparent)

      2.68

      2.68

      Water Absorption

      0.80%

      0.80%

    2. Fine Aggregate

    The gradation of fine aggregates (Fig. 3) used in this study is presented in Table3.2. On the basis of gradation results, the fine aggregates (Table 2) used in this study were of Zone II as per Table 4 of IS: 383-1970.[4]

    D. Rice Husk Ash (RHA)

    Rice Husk Ash is a Pozzolanic material. It is having different physical & chemical properties. The product obtained from R.H.A. is identified by trade name Silpoz which is much finer than cement RHA is finer than cement having very small particle size of 25 microns, so much so that it fills the interstices in between the cement in the aggregate. That is where the strength and density comes from, therefore, it can reduce the amount of cement in the concrete mix can be used in a big way to make special concrete mixes. Fig. 4 shows the sample of RHA after 1 hour of grounding.

    Fig. 3. Fine Aggregates

    Table 2. Sieve Analysis of Fine Aggregates

    Sr.

    No.

    Sieve Size

    % Passing

    Limits for Grading Zone II as per IS: 383-

    1970

    1

    10 mm

    100

    100

    2

    4.75 mm

    98.60

    90-100

    3

    2.36 mm

    96.00

    75-100

    4

    1.18 mm

    88.40

    55-90

    5

    600 micron

    38.70

    35-59

    6

    300 micron

    9.35

    8.0-30

    7

    150 micron

    1.00

    0-10

    C. Cement

    Ordinary Portland cement (Table 3) of 43 grade was used in which the composition and properties is in compliance with the Indian standard organization.

    Table 3. Properties of Cement

    S.No.

    Property Tested

    Test Results

    Standard

    Values as per IS: 4031-1988

    Test Method

    1

    Specific gravity

    3.15

    IS

    4031Part 4-1988

    2

    Initial setting time

    115

    Minutes

    Minimum30 minutes

    IS 4031

    Part –

    1988

    3

    Final setting time

    225

    Minutes

    Maximum 600 minutes

    IS 4031

    Part 5-

    1988

    4

    Compressive

    strength at 7 days

    32.11

    MPa

    IS 4031

    (Part 6-

    1988)

    Figure 3.4 . Sample of RHA after 1 hour of Grounding

  4. EXPERIMENTAL PROGRAME

    1. Concrete Mix Design

      The For M20 grade of concrete, concrete mix design is prepared as per IS 10262:2009 [6]

      1. Water content = 198 liter / m3

      2. Cement content = 396 /m3

      3. Water – cement ratio = 0.5

      4. Aggregates:

        • Coarse aggregate fraction = 0.62

        • Fine aggregate fraction = 0.38

      5. Design Mix Calculation

        a. Volume of concrete = 1m3

        b. Volume of cement = (396/3.15) x (1/1000) =

        0.126 m3

        c. Volume of water = (198/1) x (1/1000) = 0.198 m3

        1. Volume of aggregates in all – = 1-0.126-0.198 =

          0.68 m3

        2. Coarse aggregate = d) x fraction of coarse aggregate x Specific gravity (G) of coarse aggregate x 1000 = 0.68 x 0.62 x 2.73 x 1000 = 1150.97 kg/m3

        3. Fine aggregate = d) x fraction of fine aggregate x Specific gravity (G) of fine aggregate x 1000 = 0.68 x 0.38 x 2.63 x 1000 = 679.59 kg/m3

        Mix proportion of Cement, fine aggregate and coarse aggregate is 1: 1.71: 2.91.

    2. Casting

      Cubes of size 150mm x 150mm x 150mm is casting for determination of compressive strength. Cement + partially rice husk ash+ sand +coarse aggregate are mixed properly with water cement ratio as obtained in mix design and make a homogeneous mix. After 24 hr of moulding of concrete cubes are cured for 28 days.

    3. Testing

    Compressive strength of cubes is determined by compression test on compression testing machine of capacity 2000KN. For testing of compressive strength IS 516: 1959

    1. used. According to IS516:1959 [7] load of 140Kg/cm2/minute applied on the cubes until the cubes are cracks. Strength of concrete is fixed by using criteria of IS 456: 2000.

      Figure.4.1 Compressive strength testing

  5. RESULT

    Table 5.1 shows the variation of Compacting factor values with different percentage of RHA in concrete. Table 5.2 shows the variation of compressive strength of cubes with different percentage of RHA in different days

    Table5. 1: Compacting factor values of RHA concrete

    Percentage replacement of RHA(%)

    Compaction factor values

    0

    0.91

    5

    0.91

    10

    0.9

    15

    0.9

    20

    0.89

    25

    0.88

    Table5.2. Compressive strength of cubes

  6. CONCLUSION

Based on the limited study carried out on the strength behavior of Rice Husk ash, the following conclusions are drawn-

    • At all the cement replacement levels of Rice husk ash; there is gradual increase in compressive strength at certain limit.

    • The technical and economic advantages of incorporating Rice Husk Ash in concrete should be exploited by the construction and rice industries, more so for the rice growing nations of Asia.

    • Moreover with the use of rice husk ash, the weight of concrete reduces , thus making the concrete lighter which can be used as light weight construction material.

    • The pozzolonic activity of rice husk ash is not only effective in enhance the concrete strength, but also in improving the impermeability characteristics of concrete as the rice husk ash is waste material, it reduces the cost of construction.

REFERENCES

  1. J. Prasad, D.K. Jain and A.K. Ahuja, factors influencing the Sulphate resistance of cement concrete and mortar, Asian Journal Of Civil Engineering (Building And Housing) Vol. 7, Pages 259-268 (2006)

  2. P.Padma Rao, 2A.Pradhan Kumar, 3B.Bhaskar Singh, A Study on Use of Rice Husk Ash in Concrete. IJEAR Vol. 4, Issue Spl-2, Jan –

    June 2014

  3. Deepa G Nair , K. Sivaraman, and Job Thomas, Mechanical Properties of Rice Husk Ash (RHA) – High strength Concrete American Journal of Engineering Research (AJER) e-ISSN : 2320- 0847 p-ISSN : 2320-0936 Volume-3 pp-14-19(2013)

  4. IS: 383:1970 specification for coarse and fine aggregates from natural sources for concrete 2nd revision ,Bureau of Indian standard, New Delhi.

  5. IS Number : IS 2386 (Part 3):1963. Methods of test for aggregates for concrete.

  6. IS 10262:2009 Guidelines for concrete mix design proportioning Bureau of Indian standard, New Delhi.

[7] IS : 516 1959 (reaffirmed 1999) edition 1.2 (1991-07) indian standard methods of tests for strength of concrete

Percentage replacement of RHA(%)

3days

7days

28days

0

14.51

20.58

30.3

5

12.96

19.3

31.5

10

13.32

19.7

31

15

10.7

18.58

30.14

20

8.88

16.22

21

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