Project on Concrete Mix Design for various grades of Concrete

1. Concrete Mix design for M35 grade concrete with fly ash

AIM - To design Concrete Mix design for M35 grade concrete with fly ash

Introduction : Concrete mix design is the process of finding right proportions of cement, sand and aggregates for concrete to achieve target strength in structures. So, concrete mix design can be stated as Concrete Mix = Cement:Sand:Aggregates

Advantages

• It gives assurance streangth
• Design mix is more scintific than nominal mix
• Design mix widely used in More extensive and impartant concrete mix
• It is based on the laboratory Trail/error experiment mathod
• It gives desired streangth
• Mis design concrete is performance based concrete
• Admixture used Rotationally and modify the properties of concrete

Disadvantages

• Design mix time consuming
• design mix is cost is high
• Design mix needs skilled labour
• design mix needs strict supervision while adding the cement aggregates and water
• Qualty of material should be uniform else entire mix design will change

Procedure :

Data Collectio

Grade of concrete : M35 with Flyash

Type of cement : OPC 43 grade

Admixture : Super Plastisizer

Mineral admixture : Flyash

Expoure : Extreme

Specific gravity of cement : 3.15

Specific gravity of fine aggregates : 2.61

Specific gravity of coarse aggregate : 2.7

Maximum w/c ratio : 0.40

Minimum cement as per IS code : 360kg/m^3

Grade of aggregate: Zone II

methods of cocrete placing - Pumping

Workability - 150mm Slump

Type of aggregate - Crushed angular

Target steangth : f'ck=fck+1.65*S

=35+1.65*5 (S=5 from the IS10262-2019 table no 1)

=43.25 N/mm^2

Selection of water cement ratio

from IS 456 -2000 table 5 for Extreme condition max water cement - 0.40

From IS 10262 - 2019 w/c for target streangth 43.25 N/mm^2 = 0.37

Therefore w/c : 0.37

Selection of water content

Maximum water conent = 186ltr

For 150mm Slump water content = 186+(12/100)*186 = 208.32

Superplastisizer reducers 25% of water content

= 208.32*.75 = 156.24

new water content 156.24ltr

Calculating cement content

cement = 156.24/0.3 = 422.27kg/m^3 >320kg/m^3 hense OK

Cement content : 422.27kg/m^3

New cement content : 422.27*1.10 = 464.49 kg/m^3

New w/c ratio : 156.24/464.49 = 0.336

35% ge cement replaced with flyash

flyash : 0.35*464.49 = 162.57 kg/m^3

Cement : 464.27-162.57 = 301.92 kg/m^3

Weight of Admixture : 2.2% of new cement : 464.49*2.2/100 = 10.21kg/m^3

Proportioning of volume of course and fine aggregate

Volume of Course aggregate for w/c =0.37 = 0.62 (from IS10262 - 2009 table 5)

for w/c 0.5= 0.64

for w/c 0.37 =[ ((0.5-0.37)*0.01)/0.05] = 0.026

Volume of Coarse Aggregate is = 0.64+0.26=0.666

since the concrete is pumpable the volume of coarse aggregate is reduced by 10%

= 0.666 * 0.9 = 0.5994

Volume of fine Aggregate is = 1- 0.5994 = 0.40

Mix calculation

1. Volume of concrete = 1m^3
2. Volume of cement =[(mass of cement/sp.gr)*(1/1000)] = [(301.92/3.150)*(1/1000)]= 0.0958m^3
3. Volume of flyash = [(162.57/2.2)*(1/1000)] = 0.0738m^3
4. Volume of water =[(mass of water/sp.gr)*(1/1000)] =[(156.24/1)*(1/1000)]=0.156m^3
5. Volume of admixture = [(10.21/1.145)*(1/1000)] = 0.0089m^3
6. The volume other material except aggregate = 0.0958+0.0738+0.156+0.0089= 0.3345m^3
7. Volume of aggregate =a-f = 1-0.3345= 0.6655m^3
8. Mass of coarse aggregate = g*Volume of coarse aggregate*sp.gr of coarse aggregate *1000 = 0.6655*0.5994*2.7*1000 = 1077kg
9. Mass of fine aggregate = g*Volume of coarse aggregate*sp.gr of coarse aggregate *1000 =0.6655*0.40*2.61*1000 = 694.78kg

Mix Proportion

• cement = 301.92 kg/m^3
• fine aggregate = 694 kg/m^3
• Coarse aggregate = 1077 kg/m^3
• Water = 156.24kg/m^3
• admixture =10.21 kg/m^3
• flyash = 162.57 kg/m^3
• Mix proprotion is 1:2.3:3.56

2. Concrete Mix design for M50 grade concrete without fly ash

AIM - To design Mix design for M50 grade concrete without fly ash

Data collection

Garde designation - M50

Type of cement - OPC43 Grade confirming to IS 8112

Maximum Nominal Size of aggregate - 20mm

Exposure type - Extreme (reinforcement)

Minimum cement content - 360kg/m^3

methods of cocrete placing - Pumping

Workability - 100mm Slump

Type of aggregate - Crushed angular

maximum cement content - 450kg/m^3

Chemical Admixture - Super Plastisizer

Specific gravity of cement - 3.15

Specific gravity of Fine aggregate - 2.61

Specific gravity of Course aggregate- 2.73

Grade of aggregate - zone 1

Target steangth : f'ck=fck+1.65*S

=50+1.65*5 (S=5 from the IS10262-2019 table no 1)

=58.25 N/mm^2

Selection of water cement ratio

from IS 456 -2000 table 5 for severe exposure condition max water cement - 0.40

From IS 10262 - 2019 w/c for target streangth 58.25 N/mm^2 = 0.33

Selection of water content

Maximum water conent = 186ltr

For 100mm Slump water content = 186+(6/100)*186 = 197ltr

Superplastisizer reducers 29% of water content

new water content 139.87ltr

Calculating cement content

water/cement = 0,33

cement = 139.87/0.33 = 424kg/m^3 >360kg/m^3 hense OK

2.5% super plastisizer and cementanious content = (2.5/200)*424 = 10.6kg/m^3

Proportioning of volume of course and fine aggregate

Volume of Course aggregate for w/c =0.6 = 0.6 (from IS 10262-2009 table 3)

As per IS 10262- 2009 for w/c = 0.33 volume of aggregate is = 0.636

since the concrete is pumpable the volume of coarse aggregate is reduced by 10%

= 0.636 * 0.91 = 0.0.578

Volume of fine Aggregate is = 1-0.578=0.422

Mix calculation

1. Volume of concrete = 1m^3
2. Volume of cement =[(mass of cement/sp.gr)*(1/1000)] = [(424/3.150)*(1/1000)]= 0.134m^3
3. Volume of water =[(mass of water/sp.gr)*(1/1000)] =[(139.87/1)*(1/1000)]=0.139m^3
4. Super plastisizer is upto 2% of mass total cementanious content = [(10.6/1.16)*(1/1000)]=0.0092m^3
5. Volume of aggregate =a-(b+c+d) = 1-(0.134+0.139+0.0092)= 0.717m^3
6. Mass of coarse aggregate = e*Volume of coarse aggregate*sp.gr of coarse aggregate *1000 = 0.717*0.579*2.73*1000 = 1131kg
7. Mass of fine aggregate = e*Volume of coarse aggregate*sp.gr of coarse aggregate *1000 =0.717*0.422*2.61*1000 = 787kg

Mix Proportion

• cement = 424 kg/m^3
• fine aggregate = 787 kg/m^3
• Coarse aggregate = 1131 kg/m^3
• Water cement = 0.33
• admixture =10.6 kg/m^3
• Mix proprotion is 1:1.85:2.66