Project on Concrete Mix Design for various grades of Concrete

Aim of the project:-

Concret mix design for M35 grade concrete with fly ash and M50 rade concrete without fly ash.

Introduction:

power plant fuelled by coal produce a significant quality of the elecricity we consume in the world today. But in addition to elecricity, these plant produce a material that is fast becoming a vital ingradient for improving the performance of a wide range of concrete product.Fly ash is also produced as a by product from industrial plant using pulverized coal or lignite as fuel for the boiler.

Depending upon the source and the makeup of the coal being burned, the component of fly ash very considerably, but all fly ash includes substantial amount of

Silicon dioxide(Sio2)( Amorphous and crystalline)

aluminium oxide (Al2O3) &

Calcium Oxide (CaO)

Main mineral compounds in coal bearing rock strata.

A] Concret mix design for M35 grade concrete with fly ash

• Phyisical Property of FLy ash:-

Bulk density (gm/cc):-0.9-1.3

specific Gravity:- 1.6-2.6

Plasticity:- Lower or nonplastic

Shrinkage limit:- Higher

Grain size:- Major fine sand/ Silt and small percent of clay size particles

Clay (percent) :- Negligible

Free swell index:- Very low

Classification ( Texture):- Sandy silt to silty loam

Water holding capacity:-40 to 60%

Prosity(%) 30-65%

Surface area (m2/kg):- 500-5000

Lime reactivity(MPa):- 1-8

• Fly ash application:-

Fly ash can be used as prime material in blocks,paving or bricks: however, one the most imortant application is PCC pavement. PCC pavement use alarge amount of concrete and substituting fly ash provides significant economic benefits.

Benefits of fly ash:

1) Fly ash can be a cost effective substitute for portland cement in some markets.

2)It is envornmental friendly product because it is a by product and has low embodies energy.

3) Fly ash require less water than Portland cement and it is easier to use in cold weather.

4) produces various set times

5) can be used as an admixture

6) it is substitue for Portland cement.

7) great workability.

• Uses of fly ash with concrete:-

The most common use of fly ash is as a parial replacement for portland cement used in producing concrete. replacement rate normally between 20% to 30%, but can be higher. Fly ash react as a pozzolan with the lime in cement as it hydrates, creating more of the durable binder that holds concrete together.

Procedure to make Mix design :-

This selection contains specifications for the materials and requirements for the concrete to be manufactured. the specific gravity of fly ash is 2.1 to 3, while the specific gravity of GGBS is 2.85. Use the appropriate specific gravity value based on the type of admixture used.

1. Grade designation:- M35
2. Type of cement: OPC 53
3. Maximum nominal size of aggregate :-20mm
4. Minimum cement content :- 340Kg (IS456:2000 Tabl.No.5)
5. Maximum cement content:- 450Kg (As per Is code)
6. Partial replacemen of cement by fly ash :- 30% ( as per requirement)
7. Maximum Water cement ratio:- 0.45 (IS456:2000 Tabl.No.5)
8. Workability :- 100mm
9. chemical admixture :- PCS type

2] Test data for material:-

Material must be tested to finf its below physical and chemical properties. Standerd value for considered below:-

1. Cement used:- OPC53 (conferming to IS8112)
2. Specific gravity of cement :- 3.15 ( Test IS 2720)
3. Mineral admixture:- Fly ash (Conferming to IS12089)
4. Specific gravity of fly ash: 2.90
5. Chemical admixture :- 0.6% (IS9130)
6. Specific gravity

• Coase aggregate :- 2.74
• fine aggragate:- 2.74
• Admixture PCE based :- 1.12

g.Water absorption:- (IS2386)

• Coase aggregate :- 0.5%
• fine aggragate:- 1%

h. Sieve analysis:- (Test IS2386)

• Coase aggregate :- (Conferming to table 2- IS 2386)
• fine aggragate:- Zone II (Conferming to table 4- IS 2386)

3] Target strength for mix praportion of M35 grade concrete.

The strength of concrete may very depending on the quality of the material, the mixing method and the construction procedures. Therefore the target strength (fck) must be grater than the required strength of the concrete(fck)

Table 1 of IS456 gives the stander deviation value (s) for the different grade concretes.

Fck= Fck+ 1.65s

= 35+(1.65*5) (S=5 from the IS 10262 table1)

= 43.25N/mm2

4] Selection of water cement ratio:-

The maximum water cement ratios for different grades of concrete are given in table 5 Is456. you can reuce the water cement ratio based on your needs. the water cement ratio directly affects the strength of the concrete.

take it as 0.45

Maximum water content= 1.86L (Table 2 IS1026)

The water content above is for a slump of 25 to 50mm, but according to the specification our concrete requires a slump of100mm. Therefore, to get the desired slump, the water content must be increased. Cls.IS1026 recommends increasing the water content by 3% to obtain an additional 25mm slump. therefore to obtain a slump of 50mm in addition to our concrete, the water content must be increased by 6%

5]Water content for 100mm slump= 186+(0.06*186)

= 197.16L

As we use superplastisizers we can reduce the water content to gain strength in concrete.

the amount of water content = 20%

Water content required afer SP= 198-(.20*198)

= 157.73

Adoped water content =160L

6] Calculation of cement and fly ash content:

Adopted water cement ratio=0.45

Total cementatious( Cement+ fly ash) requirements= Water content/ Water cement ratio.

= 160/0.45

= 355.55kg

since flying ash is used, the amount of cementitious content (Cement+ Fly ash)

should be increased to get good performance and strength. The percentage of increasing cementitious content depends on experience and research . Here we have increased the cementitious content by 10%

Final cementitious content (Cement+ Fly ash )= 365*1.10

= 391.6

Minimum cement content requires for 'Severe' exposure= 340Kg (Is456-200 Table5)

adopted cementitious content= 391.6 > 340kg

Fly ash content requirement= 391.6*0.30 (30% replacement)

= 117.48 ~ 118 Kg

Cement content requirement = Cementitious content- Fly ash

= 391.6-117.48

= 274.12

Calculation of superspasticisers @ 0.6% to the mass of cementitious conten= 391.6*(0.6/100) = 2.35Kg

7] Coarse and fine aggregate

coarse aggregate ratio= 0.62 (Is10262) (For W/C ratio=0.5)

Coarse aggregate ratio fo 0.45 W/c =0.63 (Adding 0.01 for every decrease 0.05 and vice versa)

Final fine aggregate ratio= 0.37 (1-0.63)= 0.37

8] Mix calculations of M35 grade concrete

Volume of concrete= 1Cu.m

Total volume of cement= Cement/ (S.G.*1000)

= 275/(3.15*1000)

= 0.087 cu.m

Total volume of fly ash= Fly ash/ (S.G.*1000)

= 118/(2.5*1000)

= 0.041cu.m

Volume of water = Water/ (S.G.*1000)

= 160/(1*1000)

= 0.160Cu.m

Volume of superplastisisers= Superplasticisers/ (S.G.*1000)

= 2.35/(1.12*1000)

= 0.002 Cu.m

Total aggregate requirement = A- (B+C+D+E)

= 1-(0.087+0.041+0.160+0.002)

= 0.71 Cu.m

Coarse aggregate (C.A) = F*C.A ratio* S.G.*1000

= 0.71*0.63*2.74*1000

= 1225.6 Kg

Fine aggregate ( F.A.) = F* F.A ratio* S.G.*1000

= 0.71*0.63*2.74*1000

= 719.8 Kg

B] M50 rade concrete without fly ash.:-

1] Stipulations of concrete M50:

1. Grade Designation:- M50
2. Type of cement:- OPC 43 Grade conferming to IS 8112
3. Nominal size of aggregate:- 20mm
4. Minimum cement content:- 360Kg/m3 (From table5 of IS456-2000; Exposure condition)
5. Max. W/C ratio:- 0.35 (As per Is456:2000, IS10262,IS 4031-1968)
6. Workability:- 100mm (IS 456-2000 Cle.-7.1 Table 2)
7. Exposue condition:- Extream(for. reinforced concrete)
8. Method of concrete placing:- Pumping
9. Degree of supervision:- Good
10. Type of aggregate:- Crushed anguler aggregate
11. Maximum cement content= 450Kg/m3
12. Chemical Admixture Type:- superplastisizers

Test data for material:-

1. Cement used :- OPC 43 grade conferming to IS 8112
2. Sp.Gr. of cement:- 3.15
3. Chemical admixture:- Superplastisizer conferming to IS 9103
4. Sp. Gr. of Course aggregate:- 2.74
5. Sp. Gr. of Fine aggregate:- 2.74
6. Water absorption of C.A:- 0.5%
7. Water absorption of F.A:- 1.0%
8. Free surface moisture:- C.A & F.A- Nil
9. Sieve analysis:- C.A:- Table 2 IS code 383
10. Sieve analysis:- F.A:- Table 4 IS code 383

Target Strength of mix praportion:-

f'ck= fck+1.65S

From the table of IS 10262 :2009

Standerd Deviation = 5N/mm2

= 50+(1.65*5)

= 58.25N/mm2

Select water cement ratio:-

From table Is 456:2000 for extream exposure, max W/C=0.40

From IS code 4031:-1968 W/C ratio= 0.39

From IS code graph 10262= 0.31

Provide Water content =0.35

Selection of water content:-

From the table 2 of IS code 10262:2009, max water content for 20 mm aggregate =186 L (For 25mm to 50mm slump range estimated water content for 100mm slump)

= 186+(6/100 *186)

= 197 Lit

As superplastisizer is used, the water content can be reduced up to 20% and

above base trial water content reduction of 29% is achieved with plasticizer hence arrived content = 197*0.71

=140 Lit

Calculation of cement content:-

W/C= 0.35

Cement= 140/0.35 = 400 Kg/ m3

as a water cement ratio is lower by 0.10, the praportion of volume of C.A. is increased by 0.02(at the rate of -/+ 0.01 for every +- 0.05 change in water cement ratio therefore, corrected volume of C.A. for water cement ratio 0.35= 0.6 (IS 10262:2009 table 3)

(Note:- If C.A. may be required to be increased suitable, based on experience.)

for pumpable concrete these value are reduced by 10%

Volume of course aggregate= 0.6*0.9= 0.54

Volume of Fine aggregatem = 1-0.54=0.46

Mix material calculation:-

• Volume of concrete= (Mass of cement / Sp. gr of cement) *1/1000

= 400/3.15 *1/1000

= 0.126m3

• Volume of water= 140/1 *1/1000

= 0.14m3

• Volume of chemical admixture = (Mass of admixture / Sp. gr of admixture) *1/1000

(20%of cementitious material) = 8

= (8/ 1.145 ) *(1/1000)

= 6.98*10^-3

• Volume of course and fine aggregate= a- (b+c+d)

= 1- (0.126+0.14+6.98*10^-3)

= 0.727 m3

• Mass of course aggregate= e* Volume of courde aggregate* sp.gr of C.A.*1000

= 0.727*0.54*2.74*1000

= 1075.66m^3

• Mass of fine aggregate= e* Volume of courde aggregate* sp.gr of C.A.*1000

  = 0.727*0.46*2.74*1000

  = 916.31m^3

Result :-

For M35 grade concrete with fly ash required following quantity of material for 1 cum with praportion:-

1. Cement- 275 Kg
2. Fly ash- 118Kg
3. Fine aggregate- 720 Kg
4. Coarse aggregate-(20mm) - 1226 Kg
5. Water -160L
6. PCE grade superplastisisers-2L

following praportion should be calculated as per the quantity:

Cement: Flyash :F.A.: C.A.:water = 1:0.4:2.6:4.46:0.58

For M50 grade concrete without fly ash required following quantity of material for 1 cum with praportion:-

1. Cement-400Kg
2. Fine aggregate- 916.31 Kg
3. Coarse aggregate-(20mm) - 1075.66 Kg
4. Water -140L
5. PCE grade superplastisisers-2L

following praportion should be calculated as per the quantity:

Cement :F.A.: C.A.:water = 1:2.29:2.68:0.35