Project on Concrete Mix Design for various grades of Concrete
AIM : MIX DESIGN OF M35 GRADE CONCRETE WITH FLY ASH
STIPULATIONS FOR PROPORTIONING.
GRADE: M35
TYPE OF CEMENT : OPC 43 GRADE CONFORMING TO IS 8112
TYPE OF MINERAL ADMIXTURE : FLY ASH CONFIRMING TO IS 3812 PART1
MAXIMUM NOMINAL SIZE OF AGGREGATES : 20MM
MAXIMUM CEMENT CONTENT : 320KG/M^3
MAXIMUM WATER CEMENT RATIO : 0.45 ( TABLE : 5 IS 456-2000,BASED ON EXPOSURE CONDITION)
WORKABILITY : 100MM SLUMP VALUE FOR PUMPABLE CONCRETE
EXPOSURE CONDITION : SEVERE ( FOR REINFORCED CONCRETRE )
METHOD OF CONCRETE PLACING : PUMPING
DEGREE OF SUPERVISION : GOOD
TYPE OF AGGREGATE : CRUSHED ANGULAR AGGREGATE
MAXIMUM CEMENT CONTENT : 450 KG/M^3
CHEMICAL ADMIXTURE TYPE : SUPERPLASTICIZER
TEST DATA OF MATERIALS
CEMENT USED : OPC 43 GRADE CONFIRMING TO IS 8112
SPECIFIC GRAVITY OF CEMENT : 3.15
FLY ASH : CONFORMING TO IS 3812 PART 1
SPECIFIC GRAVITY OF FLYASH : 2.2
CHEMICAL ADMIXTURE : SUPERPLASTICIZER CONFORMING TO IS 9103
SPECIFIC GRAVITY OF :
COARSE AGGREGATE : 2.74
FINE AGGREGATE : 2.74
WATER ABSORPTION
COARSE AGGREGATE : 0.5%
FINE AGGREGATE : 1%
FREE SURFACE MOISTURE
COARSE AGGREGATE : NIL
FINE AGGREGATE : NIL
SEIVE ANALYSIS
| IS SEIVE SIZE(MM) | ANALYSIS OF CORASE AGGREGATE FRACTION | % OF DIFFRENT FRACTION | REMARKS | |||
| l | ll | l | ll | combined | confirming to table | |
| 20 | 100 | 100 | 60 | 40 | 100 | 2 of is 383 |
| 10 | 0 | 71.2 | 0 | 28.5 | 28.5 | |
| 4.75 | 9.4 | 3.7 | 3.7 | |||
| 2.36 | 0 |
FINE AGGREGATE : CONFORMING TO GRADING ZONE 1 OF TABLE 4 IS 383
TO FIND TARGET MEAN STRENGTH FOR MIX PROPORTIONING
TARGET MEAN STRENGTH f'ck = f'ck = 1.65s
= 35+1.65*5 = 43.25 N/M M2
f'ck - characteristic compressive strength
s- standard deviation
SELECTION OF WATER CEMENT RATIO.
MAX WATER CEMENT RATIO = 0.45 ( FOR SEVERE CONDITION FROM TABLE 5 OF IS 459-2000)
ON EXPERIANCE WATER CEMENT RATIO = 0.4
0.4<0.45,HENCE OK.
CALCULATION OF WATER CONTENT
MAN WATER CONTENT FOR 20MM AGGREGATE = 186 LTR ( TABLE 2 OF IS 1026:2009) FOR 25MM TO 50MM SLUMP RANGE
FOR 100 MM SLUMP = 186+(6/100)*186 = 197 LTR
AS SUPERPLASTICIZER IS USED, THE WATER CONTENT IS REDUCED UPTO 30%
BASED ON TRIALS WATER CONTENT REDUCTION OF 29% IS ACHIEVED WITH PLASTICIZER
HENCE ARRIVED WATER CONTENT = 197*0.71 = 140 LTR
CALCULATIONS OF CEMENT CONTENT
WATER CEMENT RATIO = 0.4
CEMENTATIOUS MATERIAL ( CEMENT + FLYASH ) = 140/0.4 = 350 K G/M3
IN TABLE 5 OF IS 456-2000, THE CEMENT CONTENT FOR SEVERE EXPOSURE = 320K G/M3
350 K G/M3 > 320 K G/M3
HENCE OK.
TO PROPORTION THE MIX CONTAINING FLYASH THE FOLLOWING STEPS ARE SUGGESTED:
THE PERCENTAGE OF FLYASH NEED TO BE DECIDED BASED ON PROJECT REQUIREMENT AND QUALITY OF MATERIALS
IN SOME CASES INCREASE IN CEMENTATIOUS MATERIALS CAN BE WARMED. INCRESED IN CEMENTATIOUS MATERIAL CONTENT AND ITS PERCENTAGE MAY BE BASED ON EXPERIENCE AND TRAIL
IN THIS INCREASE OF 10% CEMENTATIOUS MATERIAL CONTENT IS CONSIDERED.
CEMENTATIOUS MATERIAL CONTENT = 350*1.1 = 385K G/M3
WATER CONTENT = 140K G/M3
SO, WATER CEMENT RATIO = 140/385 = 0.364
FLYASH AT 30% TOTAL CEMENTATIOUS MATERIAL CONTENT = 35-30% = 115K G/M3
CEMENT (OPC) = 385 -115 = 270K G/M3
SAVING CEMENT WHILE USING FLYASH = 350 - 270 = 80K G/M3
FLYASH BEGIN UTILIZED = 115K G/M3
PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE CONTENT
FROM THE TABLE 3 OF IS 1026:2009, VOLUME OF COARSE AGGREGATE CORRESPONDING TO 20 MM SIZE AGGREGATE AND FINE AGGREGATE (ZONE 1) FOR WATER CEMNET RATIO = 0.6
IN PRESENT CASE WATER - CEMENT RATIO IS 0.4
THEREFORE THE VOL OF COARSE AGGREGATE NEEDS TO BE INCREASED TO DECREASE THE FINE AGGREGATE CONTENT
AS THE WATER CEMENT RATIO IS LOWERED BY 0.1 THE PROPORTION OF VOL OF COARSE AGGREGATE IS INCRESED BY 0.02 ( AT THE RATE OF +/- 0.01 FOR EVERY +/- 0.05 CHANGE IN WATER CEMENT RATIO)
HENCE THE CORRECTED VALUE OF COARSE AGGREGATE FOR THE WATER CEMENT RATIO = 0.64
( IF COARSE AGGREGATE IS NOT OF ANGULAR TYPE THEN ALSO THE VOLUME OF COARSE AGGREGATE MAY BE REQUIRED TO BE INCREASED SUITABLY BASED ON EXPERIENCE)
FOR PUMPABLE CONCRETE THESE ARE REDUCED BY 10%
VOL OF COARSE AGGREGATE = 0.64*0.9 = 0.576
VOL OF FINE AGGREGATE = 1-0.576 = 0.424
MIX CALCULATIONS
MIC CALCULATIONS PER UNIT VOL OF CONCRETE
VOL OF CONCRETE = 1M^3
VOL OF CEMENT = ( MASS OF CEMENT/SPECFIC GRAVITY OF CEMENT ) *1/1000
= (270/3.15)*1/1000 = 0.086 M3
VOL OF FLYASH = (MASS OF FLYASH / SPECIFIC GRAVITY OF FLYASH)
= (115/2.2)*1/1000 = 0.052 M3
VOL OF WATER = ( MASS OF WATER / SPECIFIC GRAVITY WATER)*1/1000
=(140//1)*1/1000 = 0.140 M3
VOL OF CHEMICAL ADMIXTURE = ( MASS OF ADMIXTURE / SPECIFIC GRAVITY OF ADMIXTURE) *1/1000
= ( 7.6/1.14)*1/1000 = 0.006 M3
VOL OF AGGREGATE ( FINE AND COARSE) = A-(B+C+D+E)
=1-(0.086+0.052+0.140+0.006) = 0.716 M3
MASS OF COARSE AGGREGATE = F* VOL OF COARSE AGGREGATE * SPECIFIC GRAVITY OF COARSE AGGREGATE *1000
= 0.716*0.424*2.74*1000 = 831K G/M3
MASS OF FINE AGGREGATE = F* VOL OF FINE AGGREGATE *SPECIFIC GRAVITY OF FINE AGGREGATE*1000
=0.716*0.424*2.74*1000 = 831K G/M3
MIX PROPORTION
CEMENT = 270K G/M3
FLYASH = 115K G/M3
WATER = 140K G/M3
FINE AGGREGATE = 831 K G/M3
COARSE AGGREGATE = 1130 K G/M3
CHEMICAL ADMIXTURE = 7K G/M3
W/C RATIO = 0.364
MIX RATIO : 1:2.15:2.94
-CLAUSE 10 : THE SLUMP SHALL BE MEASURED AND THE WATER CONTENT AND DOSAGE OF ADMIXTURE AHALL BE ADJUSTED FOR ACHIEVING THE REQUIRED SLUMP ON TRAIL. THE MIX PROPORTION SHALL BE REWORKED FOR THE ACTUAL WATER CONTENT AND CHECKED FOR DURABILITY REQUIREMENTS.
TWO OR MORE TRAILS HAVING VARIARTION OF 10% OF WATER CEMENT RATIO IN CLAUSE 10 SHALL BE CARRIED OUT AND A GRAPH BETWEEN THREE WATER CEMENT RATIOS AND CORRESPONDING STRENGTH SHALL BE PLOTTED TO WORK OUT THE MIX PROPORTIONS FOR THE GIVENTARGET STRENGTH FOR FILED TRAILS. HOWEVER DURABILITY SHALL BE MET.
RESULT: THE MIX DESIGN FOR M 35 GRADE OF CONCRETE WITH FLYASH IS 1:2.15:2.94
MIX DESIGN OF M50 GRADE CONCRETE
AIM: MIX DESIGN OF M50 GRADE OF CONCRETE
PROCEDURE
STIPULATIONS FOR PROPORTIONING
GRADE: M50
TYPE OF CEMENT : OPC 43 GRADE CONFORMING TO IS 8112
TYPE OF MINERAL ADMIXTURE : FLY ASH CONFIRMING TO IA 3812 PART1
MAXIMUM NOMINAL SIZE OF AGGREGATES : 20MM
MAXIMUM CEMENT CONTENT : 320KG/M^3
MAXIMUM WATER CEMENT RATIO : 0.45 ( TABLE : 5 IS 456-2000,BASED ON EXPOSURE CONDITION)
WORKABILITY : 100MM SLUMP VALUE FOR PUMPABLE CONCRETE
EXPOSURE CONDITION : SEVERE ( FOR REINFORCED CONCRETRE )
METHOD OF CONCRETE PLACING : PUMPING
DEGREE OF SUPERVISION : GOOD
TYPE OF AGGREGATE : CRUSHED ANGULAR AGGREGATE
MAXIMUM CEMENT CONTENT : 450 KG/M^3
CHEMICAL ADMIXTURE TYPE : SUPERPLASTICIZER
TEST DATA OF MATERIALS
CEMENT USED : OPC 43 GRADE CONFIRMING TO IS 8112
SPECIFIC GRAVITY OF CEMENT : 3.15
CHEMICAL ADMIXTURE : SUPERPLASTICIZER CONFORMING TO IS 9103
SPECIFIC GRAVITY OF :
COARSE AGGREGATE : 2.74
FINE AGGREGATE : 2.74
WATER ABSORPTION
COARSE AGGREGATE : 0.5%
FINE AGGREGATE : 1%
FREE SURFACE MOISTURE
COARSE AGGREGATE : NIL
FINE AGGREGATE : NIL
SEIVE ANALYSIS
| IS SEIVE SIZE(MM) | ANALYSIS OF CORASE AGGREGATE FRACTION | % OF DIFFRENT FRACTION | REMARKS | |||
| l | ll | l | ll | combined | confirming to table | |
| 20 | 100 | 100 | 60 | 40 | 100 | 2 of is 383 |
| 10 | 0 | 71.2 | 0 | 28.5 | 28.5 | |
| 4.75 | 9.4 | 3.7 | 3.7 | |||
| 2.36 | 0 |
FINE AGGREGATE : CONFORMING TO GRADING ZONE 1 OF TABLE 4 IS 383
TO FIND TARGET MEAN STRENGTH FOR MIX PROPORTIONING
TARGET MEAN STRENGTH f'ck = f'ck = 1.65s
= 50+1.65*5 = 58.25 N/M M2
f'ck - characteristic compressive strength
s- standard deviation
SELECTION OF WATER CEMENT RATIO.
MAX WATER CEMENT RATIO = 0.45 ( FOR SEVERE CONDITION FROM TABLE 5 OF IS 459-2000)
ON EXPERIANCE WATER CEMENT RATIO = 0.4
0.4<0.45,HENCE OK.
CALCULATION OF WATER CONTENT
MAX WATER CONTENT FOR 20MM AGGREGATE = 186 LTR ( TABLE 2 OF IS 1026:2009) FOR 25MM TO 50MM SLUMP RANGE
FOR 100 MM SLUMP = 186+(6/100)*186 = 197 LTR
AS SUPERPLASTICIZER IS USED, THE WATER CONTENT IS REDUCED UPTO 30%
BASED ON TRIALS WATER CONTENT REDUCTION OF 29% IS ACHIEVED WITH PLASTICIZER
HENCE ARRIVED WATER CONTENT = 197*0.71 = 140 LTR
CALCULATIONS OF CEMENT CONTENT
WATER CEMENT RATIO = 0.4
CEMENTATIOUS MATERIAL ( CEMENT + FLYASH ) = 140/0.4 = 350 K G/M3
IN TABLE 5 OF IS 456-2000, THE CEMENT CONTENT FOR SEVERE EXPOSURE = 320K G/M3
350 K G/M3 > 320 K G/M3
HENCE OK.
PROPORTION OF VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE CONTENT
FROM THE TABLE 3 OF IS 1026:2009, VOLUME OF COARSE AGGREGATE CORRESPONDING TO 20 MM SIZE AGGREGATE AND FINE AGGREGATE (ZONE 1) FOR WATER CEMNET RATIO = 0.6
IN PRESENT CASE WATER - CEMENT RATIO IS 0.4
THEREFORE THE VOL OF COARSE AGGREGATE NEEDS TO BE INCREASED TO DECREASE THE FINE AGGREGATE CONTENT
AS THE WATER CEMENT RATIO IS LOWERED BY 0.1 THE PROPORTION OF VOL OF COARSE AGGREGATE IS INCRESED BY 0.02 ( AT THE RATE OF +/- 0.01 FOR EVERY +/- 0.05 CHANGE IN WATER CEMENT RATIO)
HENCE THE CORRECTED VALUE OF COARSE AGGREGATE FOR THE WATER CEMENT RATIO = 0.64
( IF COARSE AGGREGATE IS NOT OF ANGULAR TYPE THEN ALSO THE VOLUME OF COARSE AGGREGATE MAY BE REQUIRED TO BE INCREASED SUITABLY BASED ON EXPERIENCE)
FOR PUMPABLE CONCRETE THESE ARE REDUCED BY 10%
VOL OF COARSE AGGREGATE = 0.64*0.9 = 0.576
VOL OF FINE AGGREGATE = 1-0.576 = 0.424
MIX CALCULATIONS
MIX CALCULATIONS PER UNIT VOL OF CONCRETE
VOL OF CONCRETE = 1M^3
VOL OF CEMENT = ( MASS OF CEMENT/SPECFIC GRAVITY OF CEMENT ) *1/1000
= (350/3.15)*1/1000 = 0.111 M3
VOL OF WATER = ( MASS OF WATER / SPECIFIC GRAVITY WATER)*1/1000
=(140//1)*1/1000 = 0.140 M3
VOL OF CHEMICAL ADMIXTURE = ( MASS OF ADMIXTURE / SPECIFIC GRAVITY OF ADMIXTURE) *1/1000
= ( 7.6/1.14)*1/1000 = 0.006 M3
VOL OF AGGREGATE ( FINE AND COARSE) = A-(B+C+D+E)
=1-(0.111+0.140+0.006) = 0.743 M3
MASS OF COARSE AGGREGATE = EX* VOL OF COARSE AGGREGATE * SPECIFIC GRAVITY OF COARSE AGGREGATE *1000
= 0.743*0.576*2.74*1000 = 1173 K G/M3
MASS OF FINE AGGREGATE = E* VOL OF FINE AGGREGATE *SPECIFIC GRAVITY OF FINE AGGREGATE*1000
=0.743*0.424*2.74*1000 = 863 K G/M3
MIX PROPORTION
CEMENT = 350 K G/M3
WATER = 140K G/M3
FINE AGGREGATE = 863 K G/M3
COARSE AGGREGATE = 1173 K G/M3
CHEMICAL ADMIXTURE = 7K G/M3
W/C RATIO = 0.4
MIX RATIO : 1:2.46:3.35
-CLAUSE 10 : THE SLUMP SHALL BE MEASURED AND THE WATER CONTENT AND DOSAGE OF ADMIXTURE SHALL BE ADJUSTED FOR ACHIEVING THE REQUIRED SLUMP ON TRAIL. THE MIX PROPORTION SHALL BE REWORKED FOR THE ACTUAL WATER CONTENT AND CHECKED FOR DURABILITY REQUIREMENTS.
TWO OR MORE TRAILS HAVING VARIARTION OF 10% OF WATER CEMENT RATIO IN CLAUSE 10 SHALL BE CARRIED OUT AND A GRAPH BETWEEN THREE WATER CEMENT RATIOS AND CORRESPONDING STRENGTH SHALL BE PLOTTED TO WORK OUT THE MIX PROPORTIONS FOR THE GIVENTARGET STRENGTH FOR FILED TRAILS. HOWEVER DURABILITY SHALL BE MET.
RESULT: THE MIX DESIGN FOR M 35 GRADE OF CONCRETE WITH FLYASH IS 1:2.46:3.35