Project on Concrete Mix Design for various grades of Concrete
Calculate the Concrete Mix Design for M35 grade concrete with fly ash :-
Aim :-
To calculate the concrete Mix design for M35 grade concrete with flyash.
Introduction :-
Concrete mix design is the method of finding the precise proportion of cement, sand and aggregate for concrete to achieve the target strength in structures, therefore concrete mix design can be stated as concrete mix in terms of Cement : Sand : Aggregates. the design is done according to the requirement of concrete strength. The fresh concrete properties like workability, setting time and hardened concrete properties like admixture, retarders etc.. The project consist of two parts, the first part deal with the design of M35 grade concrete cement with flyash.
Solution,
Step (1) Stipulations for Concrete design mix
Grade designation = M35
Type of cement OPC = 43 grade confirming to IS 8112
Type of mineral admixture = Flyash confirming to IS 3812
Maximum nominal size of aggregate = 20MM
Minimum cement content = 320 Kg/m^3 (Table 5 of IS 456:2000 Exposure condition)
Maximum water cement ratio = 0.45 (Table 5 of IS 456:2000 Exposure condition)
Workability = 100mm (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 Aggregate
Maximum cement content = 450 Kg/m^3
Chemical admixture type = Super Plasticizer conforming to IS 9103
Step (2) Test data for materials :-
Cement used = 43 grade confirming to IS 8112
Specific gravity of cement = 3.15
Flyash = confirming to IS 3812
Specific gravity of flyash = 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 %
Free surface moisture of coarse aggregate = Nill
Free surface moisture of fine aggregate = Nill
Sieve analysis coarse aggregate = Conforming to Table 2 of IS 383
Sieve analysis fine aggregate = Conforming to Grading zone ll of Table 4 of IS 383
Step (3) Target Strength for Mix Design :-
f'ck = fck + 1.65s
Where,
* f'ck = target average compressive strength at 28 days
* fck = characteristic compressive strength at 28 days
* s = standard deviation
f'ck = 35 + 1.65(5) = 43.25 N/mm^2
Target mean strength = 43.25 N/mm^2
Step (4) Selection of Water Cement Ratio :-
The maximum water cement ratio to design M35 grade concrete can be found from Table 5 of IS 456 2000
Maximum water cement ratio = 0.45
* Here, IS 10262 2019 Graph 28 day compressive strength of concrete vs Free water cement ratio
we assume water cement ratio = 0.38
* Exposure condition Severe Is 456 2000 table 5
We take water cement ratio = 0.45
Based on experience adopted water cement ratio is 0.38
0.38<0.45, Hence ok
Adopted water cement ratio = 0.38
Step (5) Selection of Water Content :-
From Table 2 of Is 10262 2009 Maximum water content for 20 mm aggregate
* 186 liter (for 25 to 50 mm slump range) every 25 mm slump add 3%
Estimated water content for 100 mm slump = 186+(6/100)x186 =197 liter.
As superplasticizer is used the water content can be reduced
superplasticizer water content reduction of 29 % has been achieved.
Water Content = 197-(29/100)x197 = 139.87 ~ 140 liters.
Water Content = 140 liters.
Step (6) Calculation of Cement and Flyas content :-
Water cement ratio = 0.38
Cementitious (Cement+Flyas ) requirement = 140/0.38 = 368.42 kg/m^3
From Table 5 of IS 456 minimum cement content for Severe Exposure condition =320 kg/m^3
368.42 kg/m^3 > 320 kg/m^3 hence, O.K
The cementitious material content has to be increased 10%
Cementitious Material = 368.42 + (10/100)368.42 = 405.262 kg/m^3
Cementitious Material = 405.262 kg/m^3
Water Content = 140 liters
So, Water cement ratio = 140/405.262= 0.345
Flyash @ 30% of total cementitious material content = 405.262 x (30/100) = 121.57 kg/m^3
Cement (OPC) = 405.262 - 121.57 = 283.68 kg/m^3
Saving of cement while using Flyash = 368.42 - 283.68 = 84.74 kg/m^3
Flyash being utilized = 121.57 kg/m^3
Step (7) Volume of coarse aggregate and fine aggregate content :-
From Table 3 of IS 10262 2009 volume of coarse aggregate corresponding to 20 mm size of aggregte Zone ll for water cement ratio of 0.50 = 0.62
In the present case water cement ratio is 0.38. Therefor volume of coarse aggregate is required to be increased to decrease the fine aggregate content. as the water cement ratio is lower by 0.10. the proportion of volume of coarse aggregate is increase by 0.02.
Therefore, corrent volume of coarse aggregate for the water cement ratio of 0.38 = 0.64
For pumpable concrete these value should be reduced by 10%
Therefore, volume of coarse aggregate = 0.64 - (10/100)x0.64 = 0.576
Volume of fine aggregate content = 1 - 0.576 = 0.424.
Step (8) Mix Calculation :-
The mix calculations per unit volume of concrete shall be as follows,
(a) Volume of concrete = 1m^3
(b) Volume of cement = (Mass of cement/ Specific gravity of cement) x (1/1000)
= (283.68/3.15) x (1/1000)
= 0.090 m^3
(c) Volume of flyash = (Mass of flyash/ Specific gravity of flyash) x (1/1000)
= (121.57/3.15) x (1/1000)
= 0.038 m^3
(d) Volume of water = (Mass of water Specific gravity of water) x (1/1000)
= (140/1) x (1/1000)
= 0.140 m^3
(e) Volume of admixture = (Mass of admixture/ Specific gravity of admixture) x (1/1000)
Mass of admixture 2% of cement naterial = (368.42x2/100) = 7.18
= (7.36/1.145) x (1/1000)
= 0.006 m^3
(f) Volume of aggregates (CA & FA) = (a-(b+c+d+e))
= (1-(0.090+0.038+0.140+0.006))
= 0.726 m^3
(g) Mass of Coarse aggregate = c x volume coarse aggregatex specific gravity of coarse aggregate x 1000
= 0.726x0.576x2.74x1000
= 1145.80 ~ 1146 kg/m^3
(h) Mass of Fine aggregate = c x volume fine aggregatex specific gravity of fine aggregate x 1000
= 0.726x0.424x2.74x1000
= 843.43 ~ 843 kg/m^3
Step (9) Mix Proportion for M35 Concrete :-
Cement = 283.68 kg/m^3
Flyash = 121.57 kg/m^3
Water = 140 l/m^3
Fine aggregate = 843 kg/m^3
Coarse aggregate = 1146 kg/m^3
Chemical admixture = 7.36 kg/m^3
Water cement ratio = 0.345
Mix Ratio for M35 = 1:2.08:2.82
Result :-
Mix proportion by weight of M35 grade of concrete with flyash is 1:2.08:2.82 ratio and its water cement ratio was found to be 0.345. Mix design is done.
Calculate the Concrete Mix Design for M50 grade concrete :-
Aim :-
To calculate the concrete Mix design for M50 grade concrete.
Introduction :-
Concrete mix design is the method of finding the precise proportion of cement, sand and aggregate for concrete to achieve the target strength in structures, therefore concrete mix design can be stated as concrete mix in terms of Cement : Sand : Aggregates. the design is done according to the requirement of concrete strength. The fresh concrete properties like workability, setting time and hardened concrete properties like admixture, retarders etc.. The project consist of the design of M50 grade concrete cement.
Solution,
Step (1) Stipulations for Concrete design mix
Grade designation = M50
Type of cement OPC = 43 grade confirming to IS 8112
Maximum nominal size of aggregate = 20MM
Minimum cement content = 320 Kg/m^3 (Table 5 of IS 456:2000 Exposure condition)
Maximum water cement ratio = 0.45 (Table 5 of IS 456:2000 Exposure condition)
Workability = 100mm (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 Aggregate
Maximum cement content = 450 Kg/m^3
Chemical admixture type = Super Plasticizer conforming to IS 9103
Step (2) Test data for materials :-
Cement used = OPC 43 grade confirming to IS 8112
Specific gravity of cement = 3.15
Flyash = confirming to IS 3812
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 %
Free surface moisture of coarse aggregate = Nill
Free surface moisture of fine aggregate = Nill
Sieve analysis coarse aggregate = Conforming to Table 2 of IS 383
Sieve analysis fine aggregate = Conforming to Grading zone ll of Table 4 of IS 383
Step (3) Target Strength for Mix Design :-
f'ck = fck + 1.65s
Where,
* f'ck = target average compressive strength at 28 days
* fck = characteristic compressive strength at 28 days
* s = standard deviation
f'ck = 50 + 1.65(5) = 58.25 N/mm^2
Target mean strength = 58.25 N/mm^2
Step (4) Selection of Water Cement Ratio :-
The maximum water cement ratio to design M50 grade concrete can be found from Table 5 of IS 456 2000
Maximum water cement ratio = 0.45
* Here, IS 10262 2019 Graph 28 day compressive strength of concrete vs Free water cement ratio
we assume water cement ratio = 0.34
* Exposure condition Severe Is 456 2000 table 5
We take water cement ratio = 0.45
Based on experience adopted water cement ratio is 0.34
0.34<0.45, Hence ok
Adopted water cement ratio = 0.34
Step (5) Selection of Water Content :-
From Table 2 of Is 10262 2009 Maximum water content for 20 mm aggregate
* 186 liter (for 25 to 50 mm slump range) every 25 mm slump add 3%
Estimated water content for 100 mm slump = 186+(6/100)x186 =197 liter.
As superplasticizer is used the water content can be reduced
superplasticizer water content reduction of 29 % has been achieved.
Water Content = 197-(29/100)x197 = 139.87 ~ 140 liters.
Water Content = 140 liters.
Step (6) Calculation of Cement and Flyas content :-
Water cement ratio = 0.34
Cementitious (Cement) requirement = 140/0.34 = 411.76 kg/m^3
From Table 5 of IS 456 minimum cement content for Severe Exposure condition = 411.76 kg/m^3
411.76 kg/m^3 > 320 kg/m^3 hence, O.K
Step (7) Volume of coarse aggregate and fine aggregate content :-
From Table 3 of IS 10262 2009 volume of coarse aggregate corresponding to 20 mm size of aggregte Zone ll for water cement ratio of 0.50 = 0.62
In the present case water cement ratio is 0.34. Therefor volume of coarse aggregate is required to be increased to decrease the fine aggregate content. as the water cement ratio is lower by 0.10. the proportion of volume of coarse aggregate is increase by 0.02.
Therefore, corrent volume of coarse aggregate for the water cement ratio of 0.34 = 0.64
For pumpable concrete these value should be reduced by 10%
Therefore, volume of coarse aggregate = 0.64 - (10/100)x0.64 = 0.576
Volume of fine aggregate content = 1 - 0.576 = 0.424.
Step (8) Mix Calculation :-
The mix calculations per unit volume of concrete shall be as follows,
(a) Volume of concrete = 1m^3
(b) Volume of cement = (Mass of cement/ Specific gravity of cement) x (1/1000)
= (411.76/3.15) x (1/1000)
= 0.130 m^3
(c) Volume of water = (Mass of water Specific gravity of water) x (1/1000)
= (140/1) x (1/1000)
= 0.140 m^3
(d) Volume of admixture = (Mass of admixture/ Specific gravity of admixture) x (1/1000)
Mass of admixture 2% of cement naterial = (411.76x2/100) = 8.23
= (8.23/1.145) x (1/1000)
= 0.007 m^3
(e) Volume of aggregates (CA & FA) = (a-(b+c+d))
= (1-(0.130+0.140+0.007))
= 0.723 m^3
(f) Mass of Coarse aggregate = c x volume coarse aggregatex specific gravity of coarse aggregate x 1000
= 0.723x0.576x2.74x1000
= 1141.067 ~ 1141 kg/m^3
(g) Mass of Fine aggregate = c x volume fine aggregatex specific gravity of fine aggregate x 1000
= 0.723x0.424x2.74x1000
= 839.95 ~ 840 kg/m^3
Step (9) Mix Proportion for M35 Concrete :-
Cement = 411.76 kg/m^3
Water = 140 l/m^3
Fine aggregate = 840 kg/m^3
Coarse aggregate = 1141 kg/m^3
Chemical admixture = 8.23 kg/m^3
Water cement ratio = 0.34
Mix Ratio for M35 = 1:2.04:2.77
Result :-
Mix proportion by weight of M50 grade of concrete is 1:2.04:2.77 ratio and its water cement ratio was found to be 0.34. Mix design is done.