partial replacement of cement with rha.pptx

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1. PARTIAL REPLACEMENT OF CEMENT IN CONCRETE WITH RICE HUSK ASH 1

2. Prepared by :- Gautam kumar singh Vivek kumar singh Brajesh kumar Deepanjan roy Akash nath Animesh mahto Hriddhiman das 2

3. content Introduction. Materials Properties of Rice Husk Ash Preliminary Test performed Mix design. Advantage and Disadvantages Conclusion 3

4. INTRODUCTION Rice husk is an agricultural waste which is produced in millions of tons. Rice husk ash (RHA) is obtained by the combustion of rice husk . Thus, due to growing environmental concern and the need to conserve energy and resources, utilization of industrial wastes as supplementary cementing materials has become an integral part of concrete construction. 4

5. RHA is very reach in silicon dioxide which makes it very reactive with lime due to its non-crystalline silica content and its specific surface. It has about 85-90% silica. This study investigated the engineering properties of RHA as a material for concrete production. The results shows that RHA is a super pozzolan and very suitable as a partial replacement of OPC. 5

6. MATERIALS Rice Husk Ash (RHA): It is used as partially replacement of cement. Cement: It is a type of binding material. Water: water is added to the concrete to perform the hydration and to make the paste workable. Aggregates: It is used as cement , sand , and water to make concrete mix. 6

7. Properties of Rice Husk Ash Physical Properties Chemical Properties Fig-1: Rice Husk Ash 7

8. Physical Properties of Rice Rusk Ash S.NO PARTICULARS PROPORTION 1 Colour Grey 2 Shape Texture Irregular 3 Mineralogy Non Crystalline 4 Particle Size >45 micron 5 Odour Odourless 6 Specific Gravity 2.3 8

9. Chemical Property of RHA S.NO PARTICULARS PROPORTION 1 Silicon Di-oxide 89.94% 2 Aluminium oxide 0.2% 3 Iron oxide 0.1% 4 Calcium oxide 0.3-2.2% 5 Magnesium oxide 0.2-0.6% 6 Sodium oxide 0.1-0.8% 7 Potassium Oxide 2.15-2.30% 8 Ignition loss 3.15-4.4% 9

10. PRELIMINARY TESTS PERFORMED Sieve Analysis: This test is performed to determine the percentage of different grain sizes. With the help of this analysis we can determine the Zone of sand. From the analysis the sand lies in the ZoneII . Sieve Size Weight retained %weight retained %passing 10mm 100 4.75mm 100 2.36mm 10 99 1.18mm 110 11 88 600 μm 480 48 40 300 μm 310 31 9 150 μm 60 6 3 Pan 30 3 10

11. Specific gravity of Aggregate Cement Specific gravity is defined as the ratio between weight of a given volume of material and weight of an equal volume of water. To determine the specific gravity of cement, kerosene is used which does not react with cement. specific gravity of the sample of the cement is 2.72. Specific gravity of coarse Aggregate is 2.7. specific gravity of the sample of sand is 2.64. 11

12. MIX DESIGN Mix design can be defined as the process of selecting suitable ingredients of concrete and determining their relative proportions with the object of producing concrete of certain minimum strength and durability as economically as possible . Steps of mix design: 1. Target Mean Strength: f ck = f ck + 1.65 σ = 35+1.65*5 = 43.25 N/mm 2 12

13. 2. Selection of w/c ratio: Assume, for 20mm nominal size water content= 186kg/m 3 Espouses condition: severe Workability= 25.50mm   3. Calculation for cement material: Weight of cement= Water content/water cement ratio = 186/0.5 kg/m 3 = 372kg/m 3 ( >250kg/m 3 ) Hence, weight of cement= 250kg/m 3 4. Aggregate calculation: Volume of coarse aggregate= 0.64* total aggregate Volume of fine aggregate= 0.36* total aggregate Volume of aggregate= 1-(weight of cement/ s c + water/1)*1/1000 = 1-(250/2.72+186/1)1/1000= 0.722m 3 Volume of coarse aggregate= 0.64*0.722= 0.462m 3   13

14. Volume of fine aggregate= 0.36*0.722=0.2599m 3 Weight of coarse aggregate= 0.462*2.72*1000= 1256.64kg Weight of fine aggregate= 0.2599*2.64*1000=686.61kg 5. Weight of all component material for per m 3 of concrete cube : Cement= 250kg/m 3 Coarse aggregate= 1257kg/m 3 Fine aggregate= 686 kg/m 3 Water= 186 kg/m 3 Replace cement with RHA by required % of weight. 14

15. Casting of cubes The process involved are: 1. Batching :- Measurement of materials . 2. Mixing :- All materials are mixed. 3. Placing :- After mixing it is placed in the mould of size (150 x 150)mm. 4. Compacting :- Tamping of concrete is done. 5. Curing :- After 24 hour we open the mould and put the cubes in the water tank for the curing. 15

16. EXPERIMENTAL WORK The fresh concrete was subjected to the following test. Compressive strength test. The compressive strength is the most important of all the properties. With the help of the Compression Testing Machine we will find out the compressive strength of the cubes casted. The result of compressive strength obtained is given below: Fig-2: Compression Testing Machine 16

17. Compressive Strength of R.h.a Concrete Compressive Strength(N/mm 2 ): Days (0% R.H.A) (5% R.H.A) 7 16.5 14.8 14 24.4 23.8 17

18. Graph Shows Variation In Compression Strength The compression strength of the concrete mix increases with replacement of rice husk ash up to a certain percent after that gradual decrease in the compressive strength is noted. The strength shown by the mix having 5% rice husk ash gives the value of compressive strength 14.8 MPa at 7th day and increases for the 14th day to 23.8 MPa. The value of compressive strength for 0%mix(conventional mix) is 16.5 MPa. Fig-3: Compressive strength vs No. of Days 18

19. Advantages Improves the compressive strength. RHA mixed concrete shows better bond strength as compared to opc cement. Permeability of concrete decreases improves compressive strength. RHA makes a role to increased resistance to chemical attack. Show better durability of concrete. Reduce the amount of cement making concrete by 20% by weight. Improves the corrosion resistance and strength of concrete as compared to that of OPC. 19

20. disadvantage Suitable incinerator/furnace as well as grinding method is required for burning and grinding rice husk in order to obtain good quality ash. Strength of concrete is reduced for larger (beyond 30%) replacement. There is a little transportation problem. Unburnt RHA is not suitable for concrete production. 20

21. Conclusion Based on the limited study carried out on the strength behaviour 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 from 3 days to 7 days. However there is significant increase in compressive strength from 7 days followed by gradual increase from 28 days. Rice husk ash can be added to cement concrete as partial replacement of cement up to 10% without any significant reduction in any of the property of concrete. As the Rice Husk Ash is waste material, it reduces the cost of construction. By using this Rice husk ash in concrete as replacement the emission of greenhouse gases can be decreased to a greater extent. 21

22. References G. V.RamaRaoand M.V.SheshagiriRao , “High performance Concrete With Rice Husk Ash as Mineral Admixture”,ICI Journal, April-June 2003, pp.17-22.6. H. B.Mahmud , B.S.Chia and N.B.A.A. Hamid, “Rice Husk Ash-An Alternative material in producing High Strength Concrete, “International Conference on Engineering Materials, June 8-11, 1997, Ottawa, Canada, pp.275- 284.8. K.Ganesan , K.Rajagopal and K.Thangavelu ,“ Effects of the Partial Replacement of Cement with Agro waste ashes (Rice husk ash and Bagasse Ash) on strength and Durability of Concrete”. Jose James and M. SubbaRao ,“Reactivity of Rice Husk Ash, “Cement and Concrete Research, Vol.16, 1986, pp.296-302.9. 22

23. 23 Thank you