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 :
The concrete mix design is a praportion of cement,sand,aggregate for concrete to achieve the greater strength in structure.This project is to Calculate the Concrete Mix Design for M35 grade concrete with fly ash & M50 grade concrete without Fly ash.
A).Calculate the Concrete Mix Design for M35 grade concrete with fly ash:
I.This section has Specifications of the materials and requirements of the concrete to be made
•Grade Designation = M35
• Type of Cement = OPC 53
• Type of Admixturev= Fly ash
• Maximum NominalSize ofAggregate = 20mm
• Minimum Cement Content =340kg Table 5-IS456
• Maximum Cement Content = 450kg Table 5-IS456
• Partial replacement of cement by Fly ash 30%as per requirement
• Maximum W/C ratio= 0.45 Table 5-IS456
• Workability= 100mm
• Chemical Admixture = PCS Type
II. TEST DATA FOR MATERIALS
Standard values are assumed below.
• Cement = OPC 53
• Specific Gravity of Cement = 3.15
• Mineral Admixture = Fly ash
• Specific Gravity of Fly ash = 2.9
• Chemical [email protected]% IS9103
• Specific Gravity of
Coarse Aggregate = 2.74
Fine Aggregate = 2.74
Admixture PCE based = 1.12
• Water Absorption Test
Coarse aggregate = 0.5 %
Fine aggregate = 1 %H
III. TARGET STRENGTH FOR MIX PROPORTIONS OF M35 GRADE CONCRETE
Table 1 of IS456
Fck= fck+1.65s
“S” from Table1-IS10262
Fck= 35+1.65×5Fck= 43.25 N/mm2
IV. SELECTION OF WATER-CEMENT RATIO
Maximum W/C ratio=0.45 Table 5-IS456
Adopted W/C ratio=0.45
V. SELECTION OF WATER CONTENT
Maximum Water Content =186 L
(Table 2-IS1026 Above water-content is for 25 to 50mm slump)
But we need 100mm slump for our concert as per specification
Increase the water-content to get the required slump
Clause 4.2 of IS1026 suggests to increases 3% of water-content to get an extra 25mm slump
Hence we to increase water content by 6% to get an additional 50mm slump for our concrete
Water-content for 100mm Slump
=186+(0.06*186)
=197.16 L
Amount of water-content to be reduced depends on the type of superplasticizer
Percentage of Reduction in water content
=20% Water content requirement
=198 – (0.20*198)
=157.73
Adopted Water Content =160 L
VI. CALCULATION OF CEMENT AND FLY ASH CONTENT
Adopted Water Cement Ratio=0.45
Total Cementitious (Cement +Fly ash) requirement= Water Content / WaterCement ratio
=160/0.45=355.55 kg
we have increased the cementitious content by 10%.
Final Cementitious
Content (Cement+Fly ash)
= 356*1.10
=391.6 kg
Minimum Cement Content required for ‘severe’ exposure=340kg Table 5-IS456
Adopted
Cementious content=391.6 kg> 340kg
Fly ash content requirement= 391.6 * 0.3030% replacement
= 117.48 ~ 118 kg
Cement Content requirement=Cementious content – Flyash
=391.6-117.48
= 274.12
Calculation of Super Plasticiers @ 0.6 percent to the mass of cementitious content
= 391.6*(0.6/100)
= 2.35 kg
VII COARSE AND FINE AGGREGATE
Coarse Aggregate ratio
= 0.62 Table3-IS10262
(For W/C =0.5))
Coarse Aggregate ratio for 0.45 w/c ratio
= 0.63(adding 0.01 for every decrease .05 and vice versa)
Final Fine Aggregate ratio
= 0.37(1-0.63) = 0.37
VIII MIX CALCULATIONS OF M35 GRADE CONCRETE
A)Volume e of Concrete= 1 cu.m
B) total Volume of Cement= Cement/(S.G*1000)
= 275/(3.15*1000)
= 0.087 cu.m
C)Total Volume of Fly ash= Flyash/(S.G*1000)
= 118/(2.5*1000)
= 0.041 cu.m
D)Volume of Water=Water /(S.G*1000)
= 160/(1*1000)
= 0.160 cu.m
E)Volume of Superplasticizers= Superplasticizers /(S.G*1000)
= 2.35/(1.12*1000)
= 0.002 cu.m
F)Total Aggregates requirement= A – (B+C+D+E)
= 1 -(0.087 +0.041+0.160+0.002)
= 0.71 cu.m
G)Coarse Aggregate (C.A)= F * C.A ratio * S.G * 1000
= 0.71*0.63 *2.74 *1000
= 1225.6 kg
H) Fine Aggregate (F.A) = F * F.A ratio * S.G * 1000
= 0.71*0.37*2.74 *1000
=719.8 kg
Cement Flyash Sand Aggregate Water and Superplasticizer needed for M35 grade concrete
MATERIALS QUANTITY
• Cement = 275 kg
• Flyash= 118 kg
• Fine Aggregate= 720 kg
• coarse Aggregate (20mm) = 1226 kg
• Water = 160 L
• PCE based SuperPlasticizer = 2 L
To find the design mix ratio divide the calculated value of all materials by the weight of cement
Mix Ratio of M35 Grade concrete by weight is
Cement : Flyash: F.A : C.A : Water =1:0.4:2.6:4.46:0.58
B).Mix Design for M50 grade concrete without fly asConcrete :
I.This section has Specifications of the materials and requirements of the concrete to be made
Grade designation : M 50
Type of cement : OPC 53 grade
Maximum nominal size of aggregate : 20 mm
Minimum cement content : 360 kg/m3 Table 5-IS456
Maximum water-cement ratio : 0.35 Table 5-IS456
Workability : 100mm
Maximum cement content : 450 kg/m3 Table 5-IS456
Chemical admixture type : Super Plasticizer
II. TEST DATA FOR MATERIALS
Cement = OPC 53
Specific gravity of cement : 3.12
Specific gravity of Coarse Aggregate : 2.74
Specific gravity of Fine Aggregate : 2.56
Water Absorption Coarse aggregate = 0.5 %
Water Absorption Fine aggregate = 1 %H
III. TARGET STRENGTH FOR MIX PROPORTIONS OF M50 GRADE CONCRETE
ftarget = fck + 1.65 x s
“S” from Table1-IS10262 standard deviation,
s = 5.0 N/mm2
ftarget = 50 + 1.65 x 5.0 = 58.25 N/mm2
IV. SELECTION OF WATER-CEMENT RATIO
Maximum water-cement ratio = 0.35 Table 5 of IS 456 : 2000
V. SELECTION OF WATER CONTENT
Maximum Water Content =186 L
(Table 2-IS1026 Above water-content is for 25 to 50mm slump)
But we need 100mm slump for our concert as per specification
Increase the water-content to get the required slump
Clause 4.2 of IS1026 suggests to increases 3% of water-content to get an extra 25mm slump
Hence we to increase water content by 6% to get an additional 50mm slump for our concrete
Water-content for 100mm Slump
=186+(0.06*186)
=197.16 L
Amount of water-content to be reduced depends on the type of superplasticizer
Based on trials with Super plasticizer water content reduction of 27% has been achievedwater content
= 197 – [197 x (27/100)]
= 143 litres.
VI. CALCULATION OF CEMENT
Water-cement ratio = 0.35
Cement content = 143/0.35
= 410 kg/m3
From Table 5 of IS 456
minimum cement content for ‘Extreme exposure’ condition = 360 kg/m3
410 kg/m3 > 360 kg/m3
hence, O.K.
VII COARSE AND FINE AGGREGATE
Coarse Aggregate ratio
= 0.62 Table3-IS10262
(For W/C =0.5))
Coarse Aggregate ratio for 0.45 w/c ratio
= 0.63(adding 0.01 for every decrease .05 and vice versa)
Final Fine Aggregate ratio
= 0.37(1-0.63) = 0.37
Therefore,
Volume of coarse aggregate = 0.65 x 0.9 = 0.585
Volume of fine aggregate content =1 – 0.585 =0.415
VIII MIX CALCULATIONS OF M50 GRADE CONCRETE
a) Volume of concrete = 1m3
b) Volume of cement = (Mass of Cement/ Its Specific Gravity ) X (1/1000)
= (410/3.12) X (1/1000)
= 0.131 m3
c) Volume of Water = (Mass of water/specific gravity of water) X (1/1000)
= (143/1) X (1/1000)
= 0.143 m3
d) Volume of Superplasticizer = (Mass of Superplasticizer / Specific gravity of admixture) X (1/1000)
= (8.2/1.145) X (1/1000)
= 0.007 m3
e) Volume of all aggregate = (a – (b + c + d))
= 1 – (0.131 + 0.143+0.007)
= 0.719 m3
e) Mass of coarse aggregate = Volume of All Aggregate X Volume of Coarse Aggregate X Specific Gravity of Coarse Aggregate X 1000
= 0.719 x 0.585 x 2.74 x 1000
= 1152.48 kg
f) Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000
= 0.719 x 0.415 x 2.56 x 1000
= 763.86 kg
MATERIALS QUANTITY
Cement = 410 kg/m3
Water = 143 kg/m3
Super plasticizer = 7 kg/m3
Fine aggregates = 763.86 kg/m3
Coarse aggregate = 1152.48 kg/m3
To find the design mix ratio divide the calculated value of all materials by the weight of cement
Mix Ratio of M50 Grade concrete by weight is
Cement : F.A : C.A : Water=1 : 1.472 : 3.043 : 0.35
RESULT :
The Concrete Mix proportion by weight of M35 grade concrete with fly ash is - 1:0.4:2.6:4.46:0.58
The Concrete Mix proportion by weight of M50 grade concrete with out fly ash - 1 : 1.472 : 3.043 : 0.35