Concrete m ix design m 15 with bottom ash

Bottom Ash

1. Concrete Mix Design with Bottom Ash 100% Replacement of Sand by Bottom Ash in Concrete M15/20mm/100%

2. Requirement

3. Bottom Ash Bottom ash ( B.A. ) is part of the non-combustible residue of coal combustion in a power plant. It is formed in a coal operated power plant while combustion and comprises traces of combustibles embedded in forming clinkers and sticking to hot side walls of a coal-burning furnace during power plant operation. The portion of the ash that escapes up the chimney or stacked is referred as fly ash. The clinkers fall by themselves into the bottom hopper of a coal-burning furnace and are then cooled & portion of the ash is referred to as bottom ash. Most bottom ash generated at power plants is stored in ash ponds, which can cause serious environmental damage. https://www.epa.gov/coalash/coal-combustion-residual-beneficial-use-evaluation-fly-ash-concrete-and-fgd-gypsum-wallboard

4. CONSIDERATIONS While mix design of concrete following considerations are taken in account: - Mix could be manually placed - Workability of mix should be +100 mm - Precautions (includes shed, water sprinkling etc.) are required for bottom ash to stack and feed in batching plants so still concrete mix has to designed as non pumpable. - Specific gravity and density of bottom ash is much less than ordinary natural sand which will lead bottom ash lesser in weight and more in volume in concrete mix. - Due to 90% of Bottom ash particle size is less than 600 micron, %age of 10 mm aggregate is increased in concrete mix considering its smaller size particles of below 10 mm & 4.75 mm could behave like sand - As bottom ash is a waste of petroleum product its water absorption is taken 0%.

5. DESIGN MIX OF M-15 grade Concrete Grade M 15 Cement OPC 43 G Ambuja Slump required +100 mm Max size of aggregate 20 mm Fine aggregate replaced 100% with B.A. W/C ratio adopted 0.56 S. Gravity of 20 mm 2.63 S. Gravity of 10 mm 2.64 S. Gravity of B.A. 1.868 S. Gravity of Admixture 1.11 20mm : 10 mm = 35 : 65 %age of B.A. in mix 30.8 % 20mm: 10mm : B.A. 24.22 : 44.98 : 30.8 % age of admixture 0.6% Cement content 300 kg/cum Admixture SIKA Viscocrete 4203 Base of Admixture PCE Placement method Manually Target strength of concrete 20 N/mm2

6. Proportion of 20 mm : 10 mm SIEVE ANALISIS Taking % of 20 mm = 35% 10 mm = 65% Sieve size (mm) Passing of Coarse agregate Combined as Graded Limits 20 mm 10 mm 40.00 100.0 100.0 100.0 100 20.00 99.7 100.0 99.9 95 - 100 10.00 1.2 82.5 54.0 25 - 55 4.75 0.0 2.4 1.6 0 - 10

7. Grading of bottom ash Dry sieve IS Sieve Size (mm) WEIGHT % WEIGHT CUMULATIVE % LIMIT AS PER IS-383 RETAINED RETAINED % RETAINED PASSING ZONE I ZONE II ZONE III ZONEIV 10 100.0 100 100 100 100 100 100 100 100 4.75 15 1.50 1.50 98.5 90 100 90 100 90 100 95 100 2.36 12 1.20 2.70 97.3 60 95 75 100 85 100 95 100 1.18 30 3.00 5.70 94.3 30 70 55 90 75 100 90 100 0.6 39 3.90 9.60 90.4 15 34 35 59 60 79 80 100 0.3 170 17.00 26.60 73.4 5 20 8 30 12 40 15 50 0.15 619 61.90 88.50 11.5 10 10 10 15 0.075 29 2.90 91.40 8.6                 Pan 86 9 100.00 0.0                 TOTAL = 1000   TOTAL CUM % RETAINED = 134.6   Fineness Modulus 1.346 % Silt & Clay Content 8.60 %   S. Gravity of B.A. 1.868

8. DETERMINATION OF COARSE AND FINE AGGREGATE Grading Zone of sand : Bottom Ash at 0.5 w/c ratio taking the %age of coarse aggregate : 0.68 Present w/c ratio : 0.56 Amount of increase of w/c ratio from 0.5 to 0.56 : 0.06 Increment of coarse aggregate @ -/+ 0.01 for every +/-0.05 change in w/c ratio : 0.692 Method of concreting at site : Manually For Pumpable Concrete Coarse aggregate can be reduced to 10 percent, hence taking reduction : 0% %age of coarse aggregate : 69.2% Therefore fine aggregate is : 30.8% In which B.A. B.A. : 100.0%   M Sand M Sand   : 0.0%

9. Mix calculations a) Volume of concrete       1 m 3 b) Volume of cement       0.095 m 3 c) Volume of fly ash       0.000 m 3 d) Volume of water       0.168 m 3 e) Volume of admixture       0.002 m 3 f) Volume of all in aggregate       0.736 m 3 g) Mass of coarse aggregate   20 mm   468.58 kg h) Mass of coarse aggregate   10 mm   873.52 kg i) Mass of fine aggregate   M. Sand   0.00 kg j) Mass of fine aggregate B.A.   423.23 kg

10. Design mix of M-15/20 mm down/100 % B.A. MATERIAL in Mix WEIGHT in kg RATIO Water 168 0.560 Cement 300 1.00 Fly Ash 0.00 Bottom Ash 423 1.41 Coarse Aggregate 1342 4.48 Admixture 1.80 0.006

11. observations Three no. trial mixes were observed and following points were recorded Concrete mix behaves like no slump/tight/less fines for first 15-20 mins and after mix itself became cohesive. Initially workability (from water adding in mix to 15-20 mins) was nil, after mix itself became workable. Above observations are due to less fineness modulus of bottom ash which initially absorbs water and then release water because of bottom ash tendency to could not retain water within its particles. Mixing of concrete in mixer requires more ( a mins x 2) times as compare to ordinary concrete mixing time ( a mins). As observed initially mix is non workable, if water added additionally mix will bleed. Slump observed after 30 min is 130 mm. Compressive strength of 7 days is 13 N/mm2 & 28 days is 21.38 N/mm2 Admixture used confirming to ASTM C-494 type G, PCE admixture @ 0.6% by wt. of cement, In case of NFB admixture it may require dosage of @1.0-1.2 % by wt. of cement In higher grade mixes of concrete bottom ash could replace natural sand 30-50%, however practice should involve to preserve bottom ash at site batching plants like prepare masonry bins to stack bottom ash, sprinkling with water over bottom ash To carryout concrete with bottom ash moisture corrections are mandatory.

12. Unit Price compression M-15 grade ordinary mix S.no Ingredient Quantity Price Total Price per cum in kg per kg per cum 1 Cement 290 4.6 1334 2 Water 156 0.01 1.56 3 Admixture 2 72 144 4 20 mm 538 0.57 306.66 5 10 mm 657 0.57 374.49 6 N.Sand 730 0.7 511 Total 2671.71 M-15 grade bottom ash mix S.no Ingredient Quantity Price Total Price per cum in kg per kg per cum 1 Cement 300 4.6 1380 2 Water 168 0.01 1.68 3 Admixture 1.8 72 129.6 4 20 mm 468 0.57 266.76 5 10 mm 873 0.57 497.61 6 B.A. 423 0.2 84.6 Total 2360.25 Total Savings of Rs. 311 is achieved which is 11.6 % less than ordinary M-15 grade concrete

13. MIX Design APPROVAL