Project on Concrete Mix Design for various grades of Concrete

AIM :-

1. To calculate the concrete mix design for M35 grade of concrete with fly ash
2. To calculate the concrete mix design for M50 grade of concrete without fly ash

INTRODUCTION :-

• Concrete is a complex material and has the right mix of constituent of concrete, which not done properly and will have adverse effect on the properties
• Concrete mix design is a systematic process of choosing economical relative of various ingredients from available material that gives the concrete of desired workability
• Concrete mix design is also depends on the mixing, batching, placing, compaction and curing.

PROCEDURE:-

1. To calculate the concrete mix design for M35 grade of concrete with fly ash
2. STEP 1 :- stipulating proportioning
3. Grade designation : M35
4. Type of cement : OPC 43 grade
5. Type of mineral admixture: Fly ash confirming to IS 3812 ( Part 1)
6. Maximum nominal size of aggregates : 20mm
7. Minimum cement content : 320 kg/m^3
8. Maximum water-cement ratio : 0.45
9. Workability :100mm slump value of pumpable concrete
10. Exposure condition : Severe
11. Method of concrete placing : Pumping
12. Degree of supervision : Good
13. Type of aggregate: Crushed angular aggregate
14. Maximum cement content : 450 kg/m^3
15. Chemical admixture type : Superplaticizer

STEP 2:- Test data for materials

1. Cement used : OPC 43 grade
2. Specific gravity of cement : 3.15
3. Fly ash : Conforming to IS 3812 part 1
4. Specific gravity of flyash : 2.2
5. Specific gravity of :-

Corse aggregate 2.74

Fine aggregate 2.74

1. Water absorption :

Corse aggregate 0.5%

Fine aggregate 1%

1. Free surface moisture

Corse aggregate nill

Fine aggregate nill

1. Seive analysis:-

Fine aggregate conforming to grding zone 1

STEP 3 :- To find target mean strength for mix proportioning

Target mean strength f'ck = fck +1.65s

35 +1.65*5 =43.25 N/mm^2

STEP 4 :- selection of water cement ratio

Maximum water-cement ratio =0.45

On experience water- cement ratio =0.4

0.4 <0.45, Hence OK.

STEP 5:- calculation of water content

Maximum water content for 20mm aggregate =186 litres ( Table 2 of IS 1026:2009) for 25mm to 50mm slump range

Hence arrived water content = 197*0.71 = 140 litres

STEP 6 :- Calculation of cement content

Water - cement ratio = 0.4

Cement +flyash = 140/0.4 =350 KG/m^3

Cementatious material content = 350*1.1 =385 KG/m^3

Water content = 140 KG/m^3

water- cement ratio = 140/385 =0.364 KG/m^3

Fly ash at 30% total cementatious material content = 35-30% =115 KG/m^3

Cement (OPC) =385-115 =270 KG/m^3

Saving of cement while using flyash = 350-270=80 KG/m^3

Fly ash beign utilized = 115 KG/m^3

STEP 7 :- proportion of volume coarse aggregate and fine aggregate

pumpable concrete, these are reduced by 10 %

Volume of coarse aggregate = 0.64*0.9 = 0.576

Volume of fine aggregate = 1-0.576 =0.424

STEP 8 :- mix calculations

1. Volume of concrete = 1 m^3
2. Volume of cement = (270/3.15 )*1/1000 =0.086m^3
3. Volume of flyash = (115/2.2) *1/1000 = 0.052m^3
4. Volume of water = (140/1)*1/1000 =0.140m^3
5. Volume of chemical admixture = ( 7.6/1.14)*1/1000 =0.006m^3
6. Volume of aggregate ( Fine and coarse) = 1-(0.086+0.052+0.140+0.006) =0.716m^3
7. Mass of coarse aggregate = 0.716*0.576*2.74*1000 =1130 kg/m^3
8. Mass of fine aggregate = 0.716*0.424*2.74*1000= 831kg/m^3

STEP 9 : - Mix proportion

1. Cement = 270 kg/m^3
2. Fly ash = 115 kg/m^3

• Water = 140 kg/m^3

1. Fine aggregate = 831 kg/m^3
2. Coarse aggregate = 1130 kg/m^3
3. Chemical admixture = 7 kg/m^3

• Water- cement ratio = 0.364

Mix ratio 1: 2.15: 2.94

STEP 10 :-

The mix design for M 35 grade of concrete with flyash is 1: 2.15:2.94

2. To calculate the concrete mix design for M50 grade of concrete without fly ash

STEP 1 :- stipulating proportioning

1. Grade designation : M50
2. Type of cement : OPC 43 grade
3. Type of mineral admixture: Fly ash confirming to IS 3812 ( Part 1)
4. Maximum nominal size of aggregates : 20mm
5. Minimum cement content : 320 kg/m^3
6. Maximum water-cement ratio : 0.45
7. Workability :100mm slump value of pumpable concrete
8. Exposure condition : Severe
9. Method of concrete placing : Pumping
10. Degree of supervision : Good
11. Type of aggregate: Crushed angular aggregate
12. Maximum cement content : 450 kg/m^3

Chemical admixture type : Superplaticizer

STEP 2:- Test data for materials

1. Cement used : OPC 43 grade
2. Specific gravity of cement : 3.15

2. Specific gravity of flyash : 2.2
3. Specific gravity of :-

Corse aggregate 2.74

Fine aggregate 2.74

1. Water absorption :

Corse aggregate 0.5%

Fine aggregate 1%

1. Free surface moisture

Corse aggregate nill

Fine aggregate nill

1. Seive analysis:-

Fine aggregate conforming to grding zone 1

STEP 3 :- To find target mean strength for mix proportioning

Target mean strength f'ck = fck +1.65s

=50+1.65*5 =58.25N/mm^2

STEP 4 :- selection of water cement ratio

Maximum water-cement ratio =0.45

On experience water- cement ratio =0.4

0.4 <0.45, Hence OK.

STEP 5:- calculation of water content

Maximum water content for 20mm aggregate =186 litres ( Table 2 of IS 1026:2009) for 25mm to 50mm slump range

Hence arrived water content = 197*0.71 = 140 litres

STEP 6 :- Calculation of cement content

Water - cement ratio = 0.4

Cement +flyash = 140/0.4 =350 KG/m^3

Cementatious material content = 350*1.1 =385 KG/m^3

Water content = 140 KG/m^3

water- cement ratio = 140/385 =0.364 KG/m^3

Fly ash at 30% total cementatious material content = 35-30% =115 KG/m^3

Cement (OPC) =385-115 =270 KG/m^3

Saving of cement while using flyash = 350-270=80 KG/m^3

Fly ash beign utilized = 115 KG/m^3

STEP 7 :- proportion of volume coarse aggregate and fine aggregate

pumpable concrete, these are reduced by 10 %

Volume of coarse aggregate = 0.64*0.9 = 0.576

Volume of fine aggregate = 1-0.576 =0.424

STEP 8 :- mix calculations

1. Volume of concrete = 1 m^3
2. Volume of cement = (350/3.15)*1/1000 =0.111m^3

1. Volume of water = (140/1)*1/1000 =0.140m^3
2. Volume of chemical admixture = ( 7.6/1.14)*1/1000 =0.006m^3
3. Volume of aggregate ( Fine and coarse) = 1-( 0.111+0.140+0.006) =0.743m^3
4. Mass of coarse aggregate = 0.743*0.576*2.74*1000= 1173kg/m^3
5. Mass of fine aggregate = 0.743*0.424*2.74*1000 =863 kg/m^3

STEP 9 : - Mix proportion

1. Cement = 350 kg/m^3

1. Water = 140 kg/m^3

• Fine aggregate = 863 kg/m^3

1. Coarse aggregate = 1173 kg/m^3
2. Chemical admixture = 7 kg/m^3
3. Water- cement ratio = 0.4

Mix ratio 1: 2.46: 3.35

STEP 10 :-

The mix design for M50 grade of concrete without flyash is 1: 2.46:3.35