Project on Concrete Mix Design for various grades of Concrete

Aim

Concrete Mix Design for M35 grade concrete with fly ash

Introduction

The main properties of concrete mix are Compressive Strength, Workability, Durability, Water Cement Ratio, Nominal size of aggregates, Grading of combined aggregates, Control of Quality at site

Procedure

Step :1 Target mean strength of concrete (f’ck)

F’ck = fck+1.65 S

Grade of designation = M35

Types of cement= OPC 43

Types od mixture = flyash

Minimum cement value =300kg/m3

Workability =100mm

Exposure condition =severe

Types of aggregate : Crushed angular aggregate

Maximum cement content =450kg/m3

Specific gravity

CA =2.74

FA =2.74

Water absorption

CA =0.5%

FA =1.0%

F’ck = fck+1.65S

Fck = 35 (M35 grade)

S= 5 N/mm2

=35+1.65*5 =43.25 N/mm2

Step:2 Water cement ratio

First Water cement ratio =0.38 (Table IS1062:2019)

Second water cement ratio =0.4

We selected lowest value of water cement ratio (because water cement ratio low, the higher the strength of concrete)

0.38<0.45 Hence ok

Step:3 Selection of water content

Max water content for 20mm agg =186 Litre

Estimated water content for 100mm slump =186+6/100*186 =197 Litre

Water content reduction 29% is achieved with plasticizer =197*0.71= 140 litre (100-29=0.71- Assume = 29)

Step:4 Calculation of cement content

Water cement ratio =0.4

Cement content = 140/0.38=368 kg/m3

368kg/m3>300kg/m3, hence ok

Step:5 Volume of Coarse Aggregate and Fine aggregate

(zone 1) water cement ratio of 0.5 =0.6

As cement water ratio is lower by 0.10, the proportion of volume of coarse aggregate is increased by 0.02

S= ((0.5-0.38)*0.01)/0.05=0.024

(Eqn=((0.5-water cement ratio/0.05)*0.1)+Volume of coarse aggregate)

Therefore 0.4=0.6+0.02=0.624

For pumpable concrete these values are reduced by 10%

Therefore, volume of coarse aggregate =0.624*0.9=0.56 (1-0.1=0.9)

Volume of fine aggregate content =1-0.56=0.44 (1 is constant)

VIII) Mix calculation

1. Volume of aggregate =1m3
2. Volume of cement= (mass of cement/specific gravity of cement)*(1/1000)

=368/3.15 * 1/1000 =0.116m3

Cementitious (10%) =368 * 1.1 =404kg/m3

Flyash (30% of cementitious )= (30/100)*404 =121.2kg/m3

Current cement used = 283 kg/m3

(Profit of cement =368-283 =85 kg/m3)

1. c) Volume of water= (mass of water/specific gravity of water)*(1/1000)

=140/1 *1/1000 =0.140m3

1. Volume of admixture= (mass of admixture/specific gravity of admixture)*(1/1000)

=7.36/1.145 *1/1000 =0.0064m3 (2% of cementitious of cementitious materials= (368*0.02=7.36)

1. Volume of aggregate (FA and CA) =(a-(b+c+d))

=1-(0.111+0.14+0.0064) =0.743m3

1. Mass of Aggregate =e * volume of CA * specific gravity of CA x 1000

= 0.743*0.56*2.74*1000 =1140 kg/m3

1. Mass of fine aggregate= e * volume of FA * specific gravity of FA x 1000

=0.743*0.44*2.74*1000 =896kg/m3

1. XI) Mix Proportion for Trail No 1

Cement = 283 kg/m3

Flyash =121.2kg/m3

Water = 140Kg/m3

Fine Aggregate =869kg/m3

Coarse Aggregate =1140kg/m3

Chemical Admixture= 7.36Kg/m3

Water cement ratio =0.38

Trail mix ratio =1 : 2.43 : 3.09

RESULT

The mix ratio of M35 Concrete with flash is 1 : 2.43 : 3.09, therefore cement is 1, fine aggregate is 2.43, and coarse aggregate is 3.09.

Trail mix ratio =1 : 2.43 : 3.09

M50 Grade without flyash

Aim

Concrete Mix Design for M50 grade concrete without fly ash

Introduction

The main properties of concrete mix are Compressive Strength, Workability, Durability, Water Cement Ratio, Nominal size of aggregates, Grading of combined aggregates, Control of Quality at site

Procedure

Step :1 Target mean strength of concrete (f’ck)

F’ck = fck+1.65 S

Grade of designation = M50

Types of cement= OPC 43

Types od mixture = without flyash

Minimum cement value =400kg/m3

Workability =100mm

Exposure condition =severe

Types of aggregate: Crushed angular aggregate

Maximum cement content =600kg/m3

Specific gravity

CA =2.74

FA =2.74

Water absorption

CA =0.5%

FA =1.0%

F’ck = fck+1.65S

Fck = 50 (M50 grade)

S= 5 N/mm2

=50+1.65*5 =58.25 N/mm2

Step:2 Water cement ratio

First Water cement ratio =0.28 (Table IS1062:2019)

Second water cement ratio =0.45

We selected lowest value of water cement ratio (because water cement ratio low, the higher the strength of concrete)

0.28<0.45 Hence ok

Step:3 Selection of water content

Max water content for 20mm agg =186 Litre

Estimated water content for 100mm slump =186+6/100*186 =197 Litre (Assume 100mm-(75-100))

Water content reduction 29% is achieved with plasticizer =197*0.71= 140 litre (100-29=0.71- Assume = 29)

Step:4 Calculation of cement content

Water cement ratio =0.4

Cement content = 140/0.28=500 kg/m3

500kg/m3>400kg/m3, hence ok

Step:5 Volume of Coarse Aggregate and Fine aggregate

(zone 1) water cement ratio of 0.5 =0.6

As cement water ratio is lower by 0.10, the proportion of volume of coarse aggregate is increased by 0.02

S= ((0.5-0.28)*0.01)/0.05=0.044

(Eqn=((0.5-water cement ratio/0.05)*0.1)+Volume of coarse aggregate)

Therefore 0.4=0.6+0.02=0.644

For pumpable concrete these values are reduced by 10%

Therefore, volume of coarse aggregate =0.644*0.9=0.58 (1-0.1=0.9)

Volume of fine aggregate content =1-0.58=0.42 (1 is constant)

VIII) Mix calculation

1. Volume of aggregate =1m3
2. Volume of cement= (mass of cement/specific gravity of cement)*(1/1000)

=500/3.15 * 1/1000 =0.158m3

1. c) Volume of water= (mass of water/specific gravity of water)*(1/1000)

=140/1 *1/1000 =0.140m3

1. Volume of admixture= (mass of admixture/specific gravity of admixture)*(1/1000)

=10/1.145 *1/1000 =0.0087m3 (2% of cementitious of cementitious materials= (500*0.02=10)

1. Volume of aggregate (FA and CA) =(a-(b+c+d))

=1-(0.158+0.14+0.0087) =0.69m3

1. Mass of Aggregate =e * volume of CA * specific gravity of CA x 1000

= 0.69*0.56*2.74*1000 =1058 kg/m3

1. Mass of fine aggregate= e * volume of FA * specific gravity of FA x 1000

=0.69*0.44*2.74*1000 =831.86kg/m3

1. XI) Mix Proportion for Trail No 1

Cement = 500 kg/m3

Water = 140Kg/m3

Fine Aggregate =831.86kg/m3

Coarse Aggregate =1058 kg/m3

Chemical Admixture= 7.36Kg/m3

Water cement ratio =0.28

Trail mix ratio =1 : 1.66 : 2.11

RESULT

The mix ratio of M50 Concrete with flash is 1 : 1.66 : 2.11, therefore cement is 1, fine aggregate is 1.66, and coarse aggregate is 2.11.

Trail mix ratio =1 : 1.66 : 2.11