#5 - Project on Concrete Mix Design for various grades of Concrete

Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash

CONCRETE MIX PROPORTIONING FOR M35 GRADE WITH FLY ASH:

I. STIPULATIONS FOR PROPORTIONING

1. GRADE DESIGNATION “ M35
2. TYPE OF CEMENT : OPC 43 GRADE CONFORMING TO IS 8112
3. MAX NOMINAL SIZE OF AGGREGATE : 20MM
4. MIN CEMENT CONTENT : 340 KG/M^3 ( FROM TABLE 5 OF IS 456: 2000- EXPOSURE CONDITION)
5. MAX WATER-CEMENT RATIO : 0.45 ( FROM TABLE 5 OF IS 456: 2000-EXPOSURE CONDITION)
6. WORKABILITY : 100MM (SLUMP VALUE FOR PUMPABLE CONCRETE)
7. EXPOSURE CONDITION : SEVERE ( FOR REINFORCEDN CONCRETE)
8. METHOD OF CONCRETE PLACING : PUMPING
9. DEGREE OF SUPERVISION : GOOD
10. TYPE OF AGGREGATE : CRUCSHED ANGULAR AGGREGATE
11. MAZ CEMENT CONTENT : 450 KG/M^3
12. CHEMICAL ADMIXTURE : SUPERPLASTICIZER

II. TEST DATA FOR MATERIALS

1. CEMENT USED : OPC 43 GRADE CONFORMING TO IS 8112
2. SPECIFIC GRAVITY OF CEMENT : 3.15
3. CHEMICAL ADMIXTURE : SUPERPLASTICIZER CONFORMING TO IS 9103
4. SPECIFIC GRAVITY OF : COARSE AGGREGATE - 2.74, FINE AGGREGATE - 2.74
5. WATER ABSORPTION : COARSE AGGREGATE - 0.5%, FINE AGGREGATE - 1.0%
6. FREE SURFACE MOISTURE: COARSE AGGREGATE - NIL, FINE AGGREGATE - NIL
7. SIEVE ALALYSIS : COARSE AGGREGATE-TABLE 2 OF IS 383 & FINE AGGREGATE - CONFORMING TO GRADING ZONE I OF TABLE 4 OF IS 383

III. TARGET STRENGTH FOR MIX PROPORTIONING:

f’ck = fck + 1.65 S

WHERE, fck = COMPRESSIVE STRENGTH OF CONCRETE & S = STANDARD DEVIATION OBTAINED FROM TABLE(IS 10262, TABLE 8)

S = 5 N/MM^2

TARGET STRENGTH = 35 + 1.65 X 5 = 43.25 N/MM^2

IV. SELECTION OF WATER-CEMENT RATIO:

TABLE 5 OF IS 456: 2000 FOR SEVERE EXPOSURE, MAX WATER-CEMENT RATIO = 0.45

USUALLY W/C RATIO IS 0.45

V. SELECTION OF WATER CONTENT:

FROM TABLE 2 OF IS 10262: 2009, MAX WATER CONTENT FOR 20MM AGGREGATE = 186 LITRE( FOR 25MM TO 50MM SLUMP RANGE)

ESTIMATED WATER CONTENT FOR 100MM SLUMP = 186 + 6/100*186 = 197 LITRE

AS SUPERPLASTICIZER IS USED, WATER CONTENT CAN BE REDUCED UPTO 20% AND ABOVE.

BASED ON TRIALS WATER CONTENT REDUCTION OF 29% IS ACHIEVED WITH PALSTICIZER.

ARRIVED WATER CONTENT = 197*0.71 = 140 LITRE

VI. CALCULATION OF CEMENT CONTENT:

W/C RATIO = 0.4

CEMENT CONTENT = 140/0.4 = 350 KG/M^3

FROM TABLE 5 OF IS 456 MIN CEMENT CONTENT FOR ‘SEVERE’ EXPOSURE CONDITION = 320 KG/M^3

350 KG/M^3 > 320 KG/M^3, HENCE OK.

10% INC IN CEMENTITIOUS MATERIAL CONTENT.

CEMENTITIOUS MATERIAL CONTENT = 350 * 1.10 = 385 KG/M3

WATER CONTENT = 140 KG/M3

WATER-CEMENT RATIO = 140/385 = 0.364

FLY ASH @ 30% TOTAL CEMENTITOUS MATERIAL CONTENT = 385*30% = 115 KG/M3

CEMENT(OPC) = 385 - 115 = 270 KG/M3

SAVING OF CEMENT WHILE USING FLY ASH = 350 - 270 = 80KG/M3

FLY ASH BEING UTILIZED = 115 KG/M3

VII. PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE CONTENT:

FROM TABLE 3 OF IS 10262: 2009, VOLUME OF COARSE AGGREGATE CORRESPONDING TO 20MM SIZE AGGREGATE AND FINE AGGREGATE (ZONE I) FOR WATER-CEMENT RATIO = 0.6

IN PRESENT CASE W/C RATIO IS 0.40

SO, VOL OF COARSE AGGREGATE NEEDS TO BE INC TO DEC THE FINE AGGREGATE CONTENT

AS W/C RATIO IS LOWER BY 0.10, PROPORTION OF VOLUME OF COARSE AGGREGATE IS THEREFORE INCREASED BY 0.02(AT THE RATE OF -/+ 0.01 FOR EVERY +/- 0.05 CHANGE IN WATER CEMENT RATIO.

THEREFORE, CORRECTED VOL OF CAORSE AGGREGATE FOR THE W/C RATIO OF 0.40 = 0.62

FOR PUMPABLE CONCRETE THESE VALUES ARE REDUCED BY 10%

THEREFORE, VOL OF COARSE AGGREGATE = 0.62 X 0.9 = 0.56

VOL OF FINE AGGREGATE CONTENT = 1 - 0.56 = 0.44

VIII. MIX CALCULATIONS:

a) VOL OF CONCRETE = 1 M^3

b) VOL OF CEMENT = MASS OF CEMENT/ SPECIFIC GRAVITY OF CEMENT * (1/1000) = 270/3.15 *(1/1000) = 0.086 M3

c) VOL OF FLY ASH = MASS OF FLY ASH/ SPECIFIC GRAVITY OF FLY ASH * (1/1000) = 115/2.2 *(1/1000) = 0.052 M3

d) VOL OF WATER = MASS OF WATER / SPECIFIC GRAVITY OF WATER * (1/100) = 140/1 * (1/1000) = 0.140 M3

e) VOL OF CHEMICAL ADMIXTURE = MASS OF CHEMICAL SUBSTANCE/ SPECIFIC GRAVITY OF ADMIXTURE * (1/1000) = 7.6/1.145 * (1/1000) = 0.006 M^3

MASS OF CHEMICAL ADMIXTURE - 2% OF CEMENTITIOUS MATERIAL = (350*2/100) = 7

f) VOL OF AGGREGATE (FA & CA) = (a-(b+c+d+e)) = (1-(0.086+0.052+0.14+0.006)) = 0.716 M^3

g) MASS OF COARSE AGGREGATE = e X VOL OF COARSE AGGREGATE X SPECIFIC GRAVITY OF COARSE AGGREGATE X 1000 = 0.7160.562.74*1000 = 1098 KG/M^3

h) MASS OF FINE AGGREGATE = e X VOL OF FINE AGGREGATE X SPECIFIC GRAVITY OF FINE AGGREGATE X 1000 = 0.7160.442.74*1000 = 863 KG/M^3

IX. MIX PROPORTIONS FOR TRIAL NUMBER 1:

CEMENT = 270 KG/M^3

FLY ASH = 115 KG/M3

WATER = 140 KG/M^3

FINE AGGREGATE = 863 KG/M^3

COARSE AGGREGATE = 1098 KG/M^3

CHEMICAL ADMIXTURE = 7 KG/M^3

WATER-CEMENT RATIO = 0.364

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CONCRETE MIX PROPORTIONING FOR M50 GRADE WITHOUT FLY ASH:

I. STIPULATIONS FOR PROPORTIONING

1. GRADE DESIGNATION “ M50
2. TYPE OF CEMENT : OPC 43 GRADE CONFORMING TO IS 8112
3. MAX NOMINAL SIZE OF AGGREGATE : 20MM
4. MIN CEMENT CONTENT : 340 KG/M^3 ( FROM TABLE 5 OF IS 2=456: 2000- EXPOSURE CONDITION)
5. MAX WATER-CEMENT RATIO : 0.45 ( FROM TABLE 5 OF IS 456: 2000-EXPOSURE CONDITION)
6. WORKABILITY : 100MM (SLUMP VALUE FOR PUMPABLE CONCRETE)
7. EXPOSURE CONDITION : SEVERE ( FOR REINFORCEDN CONCRETE)
8. METHOD OF CONCRETE PLACING : PUMPING
9. DEGREE OF SUPERVISION : GOOD
10. TYPE OF AGGREGATE : CRUCSHED ANGULAR AGGREGATE
11. MAZ CEMENT CONTENT : 450 KG/M^3
12. CHEMICAL ADMIXTURE : SUPERPLASTICIZER

II. TEST DATA FOR MATERIALS

1. CEMENT USED : OPC 43 GRADE CONFORMING TO IS 8112
2. SPECIFIC GRAVITY OF CEMENT : 3.15
3. CHEMICAL ADMIXTURE : SUPERPLASTICIZER CONFORMING TO IS 9103
4. SPECIFIC GRAVITY OF : COARSE AGGREGATE - 2.74, FINE AGGREGATE - 2.74
5. WATER ABSORPTION : COARSE AGGREGATE - 0.5%, FINE AGGREGATE - 1.0%
6. FREE SURFACE MOISTURE: COARSE AGGREGATE - NIL, FINE AGGREGATE - NIL
7. SIEVE ALALYSIS : COARSE AGGREGATE-TABLE 2 OF IS 383 & FINE AGGREGATE - CONFORMING TO GRADING ZONE I OF TABLE 4 OF IS 383

III. TARGET STRENGTH FOR MIX PROPORTIONING:

f’ck = fck + 1.65 S

WHERE, fck = COMPRESSIVE STRENGTH OF CONCRETE & S = STANDARD DEVIATION OBTAINED FROM TABLE(IS 10262, TABLE 8)

S = 5 N/MM^2

TARGET STRENGTH = 50 + 1.65 X 5 = 58.25 N/MM^2

IV. SELECTION OF WATER-CEMENT RATIO:

TABLE 5 OF IS 456: 2000 FOR SEVERE EXPOSURE, MAX WATER-CEMENT RATIO = 0.45

USUALLY W/C RATIO IS 0.45

V. SELECTION OF WATER CONTENT:

FROM TABLE 2 OF IS 10262: 2009, MAX WATER CONTENT FOR 20MM AGGREGATE = 186 LITRE( FOR 25MM TO 50MM SLUMP RANGE)

ESTIMATED WATER CONTENT FOR 100MM SLUMP = 197.16 LITRE

AS SUPERPLASTICIZER IS USED, WATER CONTENT CAN BE REDUCED UPTO 20% AND ABOVE.

BASED ON TRIALS WATER CONTENT REDUCTION OF 29% IS ACHIEVED WITH PALSTICIZER.

ARRIVED WATER CONTENT = 197.16*0.71 = 139.98 LITRE

SPECIFIC GRAVITY OF SUPERPLASTICIZER = 2.1

VI. CALCULATION OF CEMENT CONTENT:

W/C RATIO = 0.4

CEMENT CONTENT = 139.98/0.4 = 349.95 KG/M^3

FROM TABLE 5 OF IS 456 MIN CEMENT CONTENT FOR ‘SEVERE’ EXPOSURE CONDITION = 320 KG/M^3

349.95 KG/M^3 > 320 KG/M^3, HENCE OK.

10% INC IN CEMENTITIOUS MATERIAL CONTENT.

CEMENTITIOUS MATERIAL CONTENT = 349.95 * 1.10 = 384.945 KG/M3

WATER CONTENT = 139.98 KG/M3

WATER-CEMENT RATIO = 139.98/384.945 = 0.363

VII. PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE CONTENT:

FROM TABLE 3 OF IS 10262: 2009, VOLUME OF COARSE AGGREGATE CORRESPONDING TO 20MM SIZE AGGREGATE AND FINE AGGREGATE (ZONE I) FOR WATER-CEMENT RATIO = 0.6

IN PRESENT CASE W/C RATIO IS 0.363

SO, VOL OF COARSE AGGREGATE NEEDS TO BE INC TO DEC THE FINE AGGREGATE CONTENT

AS W/C RATIO IS LOWER BY 0.10, PROPORTION OF VOLUME OF COARSE AGGREGATE IS THEREFORE INCREASED BY 0.02(AT THE RATE OF -/+ 0.01 FOR EVERY +/- 0.05 CHANGE IN WATER CEMENT RATIO.

THEREFORE, CORRECTED VOL OF COARSE AGGREGATE FOR THE W/C RATIO OF 0.40 = 0.48

FOR PUMPABLE CONCRETE THESE VALUES ARE REDUCED BY 10%

THEREFORE, VOL OF COARSE AGGREGATE = 0.48 X 0.9 = 0.435

VOL OF FINE AGGREGATE CONTENT = 1 - 0.435 = 0.564

VIII. MIX CALCULATIONS:

a) VOL OF CONCRETE = 1 M^3

b) VOL OF CEMENT = MASS OF CEMENT/ SPECIFIC GRAVITY OF CEMENT * (1/1000) = 270/3.15 *(1/1000) = 0.086 M3

c) VOL OF WATER = MASS OF WATER / SPECIFIC GRAVITY OF WATER * (1/100) = 140/1 * (1/1000) = 0.140 M3

d) VOL OF CHEMICAL ADMIXTURE = MASS OF CHEMICAL SUBSTANCE/ SPECIFIC GRAVITY OF ADMIXTURE * (1/1000) = 7.6/1.145 * (1/1000) = 0.006 M^3

MASS OF CHEMICAL ADMIXTURE - 2% OF CEMENTITIOUS MATERIAL = (350*2/100) = 7

f) VOL OF AGGREGATE (FA & CA) = (a-(b+c+d)) = (1-(0.086+0.052+0.14+0.006)) = 0.856 M^3

g) MASS OF COARSE AGGREGATE = e X VOL OF COARSE AGGREGATE X SPECIFIC GRAVITY OF COARSE AGGREGATE X 1000 = 0.8560.4352.74*1000 = 1020 KG/M^3

h) MASS OF FINE AGGREGATE = e X VOL OF FINE AGGREGATE X SPECIFIC GRAVITY OF FINE AGGREGATE X 1000 = 0.8560.5642.74*1000 = 1322 KG/M^3

IX. MIX PROPORTIONS FOR TRIAL NUMBER 1:

CEMENT = 349.95 KG/M^3

WATER = 139.98 KG/M^3

FINE AGGREGATE = 1322 KG/M^3

COARSE AGGREGATE = 1020 KG/M^3

CHEMICAL ADMIXTURE = 7 KG/M^3

WATER-CEMENT RATIO = 0.363