Project on Concrete Mix Design for various grades of Concrete
AIM: To Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash
INTRODUCTION:
Concrete mix design is to find the accurate proportion of various materials in concrete mix such as Cement, Water,Coarse Aggregate,Plasticiser,Fine Aggregate. Concrete mix design is also depends upon the properties of the above mentioned materials. It is done inorder to provide proper strength of concrete. Here two Mix Design has to be done Part One Mix Design for M35 grade with fly ash and M50 grade without flyash.
OBJECTIVE:
The objective is to calculate MIX DESIGN for M35 grade with Fly Ash and M50grade without FLyash. The design mix is based on IS Methods.
PART 1 Calculate Mix Design for M35 grade with FLY ASH
STEP 1: DATA
Grade designation M35
Type of cement OPC 43 Grade confirming to IS 8112
Type of mineral admixture Fly ash confirming to IS 3812 (Part 1)
Maximum nominal size of aggregate 20 mm
Minimum cement content 320 kg/m3 (Table 5 of IS 456:2000- Exposure condition)
Maximum water-cement ratio 0.45 (Table 5 of IS 456:2000 Exposure condition)
Workability 100 mm (slump value for pumpable concrete)
Exposure condition Severe (For Reinforced Concrete)
Method of concrete placing Pumping
Degree of supervision Good
Type of aggregate Crushed Angular Aggregates
Maximum cement content 450 kg/m3
Chemical admixture type Super Plasticizer
Cement used OPC 43 Grade conforming IS 8112
Specific gravity of cement 3.15
Fly ash confirming to IS 3812 (Part 1)
Specific gravity of fly ash 2.2
Chemical admixture Super Plasticizer conforming to IS 9103
Specific gravity of coarse aggregate 2.74
Specific gravity of fine aggregate 2.74
Water absorption of coarse aggregate 0.5%
Water absorption of fine aggregate 1.0%
Sieve analysis: Coarse aggregate Conforming to Table 2 of IS 383
Sieve analysis: Fine aggregate Conforming to Grading Zone II of Table 4 of IS 383
STEP 2 : TARGET MEAN STRENGTH
ft =fck + 1.65s
Where,
ft = Target Mean Strength
fck = Compressive mean strength
S= Standard deviation from table 1 IS 10262: 2009
Ft= 35+1.65*5=43.25 N/mm^2
Target Mean Strength=43.25 N/mm^2
STEP 3: WATER CEMENT RATIO
The Maximum W/c Ratio refering to table 5 of IS 456:2000=0.45
The W/c ratio refering to IS 10262:2019 fig 1 = 0.44
W/C =0.4 is adopted
STEP 4 : WATER CONTENT
Maximum Water content for 20 mm agg=186 litre (Refer Table 2 of IS 10262:2009)
Clause 4.2 suggests increasing of 3% of water content for every extra 25mm slump from 50mm slump. So a 6% is to be added to it
Estimated Water content = 186+(6/100)*186=197 Litre
Based on trials with Super plasticizer water content reduction of 20% has been achieved, Hence the arrived water content
Water content required = 197*0.8=158 Litre
Water Content= 158 Litre
STEP 4 : CALCULATE CEMENT CONTENT
W/C ratio as adopted in step 3=0.44
Total Cement Material =(Cement+Fly Ash)
Water Content/ W/C ratio=0.44
Cementetious material=158/0.44=359 Kg/Cu.m
Final Cementetious =359*1.1=395 Kg
Final Cementetious =395 Kg/Cu.m
Final Cementetious >Minimum cement content as shown in Table 5 of IS 456:2000
359Kg/cu.m>320 Kg/cu.m, Hence Ok
Final Cementatious content = 359Kg/Cu.m
NOW water cement ratio =395/158=0.44
Fly ash content is taken as 30% of the total cementitious content = 0.3*395 Kg/cu.m= 118.5 Kg/Cu.m
Fly ash content= 118.5 Kg/Cu.m
Cement content = Final Cementatious content- Fly ash content
Cement Content= 359 Kg/Cu.m-118.5 Kg/Cu.m
Cement Content = 277 Kg/Cu.m
STEP 5 : VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE
From Table 3 of IS 10262 : 2009 Volume of CA for zone II is 0.62 for W/C ratio of 0.5. But here the W/c ratio is 0.44 with a difference of 0.06
For every 0.05 diffrence in Water cement ratio the Coarse Aggregate is increased by 0.01, i.e(0.06/0.05=1.2 times of 0.01)Therefore in this case the Coarse Aggregate is increased by 0.01*1.2=0.012
Therefore the corrected proportion of CA for 0.44 water cement ratio=0.62+0.012=0.632
For pumpable concrete the volume of Coarse Aggregate is reduced by 10%
Thus, Volume of CA=0.632*0.9=0.568
Volume of Fine Aggregate= 1-0.568=0.432
STEP 6) MIX CALCULATION
Volume of Concrete= 1m^3
Volume of Cement = (mass of cement/Specific gravity of cement)*(1/1000)=(277/3.15)*(1/1000)=0.087 Cu.m
Volume of Cement =0.087 Cu.m
Volume of Fly Ash = (mass of fly ash/Specific gravity of cement)*(1/1000)=(118/2.2)*(1/1000)=0.053 Cu.m
Volume of Fly Ash =0.053 Cu.m
Volume of Water=(mass of water/Specific gravity of Water)*(1/1000)=(158/1)*(1/1000)=0.158 Cu.m
Volume of Water=0.158 Cu.m
Volume of chemical admixture(superplasticizer) =(mass of admixture/Specific gravity of admixture)*(1/1000)=(7.9/1.145)*(1/1000)=0.006 Cu.m
Volume of chemical admixture(superplasticizer)=0.006 Cu.m (NOTE: MASS OF ADMIXTURE =0.02*395=7.9Kg)
Volume of all in Aggregate=1-(Volume of cement+Volume of Fly ash+Volume of Water+Volume of Admixture)=1-(0.087+0.053+0.158+0.006)=0.696 Cu.m
Volume of all in Aggregate=0.696 Cu.m
Mass of Coarse Aggregate = Volume of all in aggregate* volume of coarse aggregate* specific gravity of coarse aggregate*1000=
=0.696*0.568*2.74*1000
Mass of Coarse Aggregate=1083 Kg/Cu.m
Mass of Fine Aggregate=Volume of all in aggrate* volume of coarse aggregate* specific gravity of coarse aggregate*1000
=0.696*0.432*2.74*1000
Mass of Fine Aggregate= 823 Kg/Cu.m
STEP 7) MIX PROPORTION
i)CEMENT= 277 Kg/Cu.m
ii) Fly Ash=118 Kg/Cu.m
ii)WATER= 158 Litr/Cu.m
iii)Coarse Aggregate= 1083 Kg/Cu.m
iv) Fine Aggregate=823 Kg/Cu.m
V) Admixture=7.9 Kg/Cu.m
vi) Water Cement Ratio=0.4 (lowest is selected)
MIX PROPORTION BY WEIGHT =1:2.08:2.74
PART 2 Calculate Mix Design for M50 grade without FLY ASH
STEP 1: DATA
Grade designation M50
Type of cement OPC 53 Grade
Maximum nominal size of aggregate 20 mm
Minimum cement content 320 kg/m3 (Table 5 of IS 456:2000- Exposure condition)
Maximum water-cement ratio 0.45 (Table 5 of IS 456:2000 Exposure condition)
Workability 100 mm (slump value for pumpable concrete)
Exposure condition Severe (For Reinforced Concrete)
Method of concrete placing Pumping
Degree of supervision Good
Type of aggregate Crushed Angular Aggregates
Maximum cement content 450 kg/m3
Chemical admixture type Super Plasticizer
Specific gravity of cement 3.15
Chemical admixture Super Plasticizer conforming to IS 9103
Specific gravity of coarse aggregate 2.74
Specific gravity of fine aggregate 2.64
Water absorption of coarse aggregate 0.5%
Water absorption of fine aggregate 1.0%
Sieve analysis: Coarse aggregate Conforming to Table 2 of IS 383
Sieve analysis: Fine aggregate Conforming to Grading Zone II of Table 4 of IS 383
STEP 2 : TARGET MEAN STRENGTH
ft =fck + 1.65s
Where,
ft = Target Mean Strength
fck = Compressive mean strength
S= Standard deviation from table 1 IS 10262: 2009
Ft= 53+1.65*5=58.25 N/mm^2
Target Mean Strength=58.25 N/mm^2
STEP 3: WATER CEMENT RATIO
The Maximum W/c Ratio refering to table 5 of IS 456:2000=0.45
The W/c ratio refering to IS 10262:2019 fig 1 = 0.44
W/C =0.44 is adopted
STEP 4 : WATER CONTENT
Maximum Water content for 20 mm agg=186 litre (Refer Table 2 of IS 10262:2009)
Clause 4.2 suggests increasing of 3% of water content for every extra 25mm slump from 50mm slump. So a 6% is to be added to it
Estimated Water content = 186+(6/100)*186=197 Litre
Based on trials with Super plasticizer water content reduction of 20% has been achieved, Hence the arrived water content
Water content required = 197*0.8=158 Litre
Water Content= 158 Litre
STEP 4 : CALCULATE CEMENT CONTENT
W/C ratio as adopted in step 3=0.44
Water Content/ W/C ratio= Cement Content
Cement Content=158/0.44=359 Kg/Cu.m
Cement Content >Minimum cement content as shown in Table 5 of IS 456:2000
359Kg/cu.m>320 Kg/cu.m, Hence Ok
Cement Content Required = 359Kg/Cu.m
STEP 5 : VOLUME OF COARSE AGGREGATE AND FINE AGGREGATE
From Table 3 of IS 10262 : 2009 Volume of CA for zone II is 0.62 for W/C ratio of 0.5. But here the W/c ratio is 0.44 with a difference of 0.06
For every 0.05 diffrence in Water cement ratio the Coarse Aggregate is increased by 0.01, i.e. (0.06/0.05=1.2 times of 0.01). Therefore in this case the Coarse Aggregate is increased by 1.2*0.01=0.012
Therefore the corrected proportion of CA for 0.4 water cement ratio=0.62+0.012=0.632
For pumpable concrete the volume of Coarse Aggregate is reduced by 10%
Thus, Volume of CA=0.632*0.9=0.568
Volume of Fine Aggregate= 1-0.568=0.442
STEP F) MIX CALCULATION
Volume of Concrete= 1m^3
Volume of Cement = (mass of cement/Specific gravity of cement)*(1/1000)=(359/3.15)*(1/1000)=0.114 Cu.m
Volume of Cement =0.114 Cu.m
Volume of Water=(mass of water/Specific gravity of Water)*(1/1000)=(158/1)*(1/1000)=0.158 Cu.m
Volume of Water=0.158 Cu.m
Volume of chemical admixture(superplasticizer) =(mass of admixture/Specific gravity of admixture)*(1/1000)=(7.9/1.145)*(1/1000)=0.006 Cu.m
Volume of chemical admixture(superplasticizer)=0.006 Cu.m (NOTE: MASS OF ADMIXTURE =0.02*395=7.9Kg)
Volume of all in Aggregate=1-(Volume of cement+Volume of Water+Volume of Admixture)=1-(0.114+0.158+0.006)=0.722 Cu.m
Volume of all in Aggregate=0.722 Cu.m
Mass of Coarse Aggregate = Volume of all in aggregate* volume of coarse aggregate* specific gravity of coarse aggregate*1000=
=0.722*0.568*2.74*1000
Mass of Coarse Aggregate=1123 Kg/Cu.m
Mass of Fine Aggregate=Volume of all in aggrate* volume of coarse aggregate* specific gravity of coarse aggregate*1000
=0.722*0.442*2.74*1000
Mass of Fine Aggregate= 874 Kg/Cu.m
STEP G) MIX PROPORTION
i)CEMENT= 359 Kg/Cu.m
ii)WATER= 158 Ltr/Cu.m
iii)Coarse Aggregate= 1123 Kg/Cu.m
iv) Fine Aggregate=874 Kg/Cu.m
V) Admixture=7.9 Kg/Cu.m
vi) Water Cement Ratio=0.44 (lowest is selected)
MIX PROPORTION BY WEIGHT =1:2.43:3.12