Project on Concrete Mix Design for various grades of Concrete
MIX DESIGN FOR M35 CONCRETE WITH FLY ASH AND M50 GRADE OF CONCRETE:-
Mix design for M35 grade concrete with fly ash:-
codes: IS 456-2000 , IS 1026:2009
OBJECTIVE: Calculation of concrete mix design of M35 grade of concrete with fly ash
PROCEDURE:
Step :1
Stipulations for proportioning
- Grade designation : M35
- Type of cement: opc 43 grade conforming to IS 8112
- Type of mineral admixture: Fly ash confirming to IS3812
- Maximum nominal size of aggregates:20mm
- Minumum cement content:320kg/m^3( Table:5 IS 456-2000,based on exposure condition)
- Maximum water- cement ratio: 0.45 ( Table:5 IS 456-2000,based on exposure condition)
- Workability:100mm slump value of pumpable concrete
- Exposure condition: Severe ( for reinforced concrete)
- Method of concrete placing: pumping
- Degree of supervision: Good
- Type of aggregate: Crushed angular aggregate
- Maximum cement content: 450 kg/m^3
- Chemical admixture type: superplaticizer.
Step:2
Test data for materials
- cement used : opc 43 grade confirming to IS8112
- specific gravity of cement: 3.15
- Fly ash : conforming to IS38112 part 1
- specific gravity of flyash :2.2
- chemical admixture : superplaticizer conforming to IS9103
- specific gravity of: coarse aggregate=2.74 , fine aggregate=2.74
- Water absorption: coarse aggregate:0.5% Fine aggregate:1%
- Free surface moisture: coarse aggregate: nil ,Fine aggregate:nil
- seive analysis: coarse aggregates, Fine aggregates: conforming to grading zone 1 table 4 IS 383.
step: 3
To find target mean strength for mix proportioning
traget mean stength f' ck =fck+1.65s = 35+1.65*5=43.25n/mm^2
fck- charateristic compressive strength
s- standrad deviation
step:4
selection of water-cement ratio
Maximum water-cement ratio =0.45 (for sever condition, from table 5 of IS456-2000)
on experence 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
for 100mm slump range=186+(6/100)*186=197litres
As superplaticizer is used, the water content is reduced upto 30%
based on trails water content reduction of 29% is achived with plasticizer
Hence arrived water content= 197*0.71=140litres
step:6
Calculation of cement content
Water-cement ratio= 0.4
Cementatious material (cement+flyash)= 140/0.4 = 350 kg/m^3
In table 5 of IS456-2000,the cement content for severe exposure=320 kg/m^3
350kg/m^3 > 320kg/m^3 hence ok
To the proportion mix containing flyash the following steps are suggested: -
- The percentage of fly ash need to be decided based on the project requirment and quality of material.
- in some cases increase in cementatious material can be warned. increase in cementatious material content and its precentage may be based on experience and trail, In this increse of 10% cementatious material content is considered
cementatious material content= 350*1.1
= 385kg/m^3
water content = 140kgm^3
so, water-cement ratio = 140/385
=0.364
Fly ash at 30% total cementatious material content=35-30%=115kg/m^3
saving of cement while using flyash = 350-270=80kg/m^3
fly ash being utilized = 115kg/m^3
step:7
proportion of volume of coarse aggregate and fine aggregate content:
From table 3 of IS1026:2009, volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone1) for water cement ratio is 0.4
Therfore the volume of coarse aggregate needs to be incresed to decrease the fine aggregate content.
As the water-cement ratio is lowered by 0.1, the proportion of volume of coarse aggregate is incresed by 0.02 (at the rate of +/- 0.01 for every +/- 0.05 change in water-cement ratio)
Hence the corrected value of coarse aggregate for water cement ratio= 0.64
For pumpable concrete these are reduced by 10%
volume of fine aggregate = 1-0.576
= 0.424
volume of coarse aggregate = 0.64*-0.9
= 0.576
step:8
mix calculations:
Mix calculation per unit volume of concrete
a. voulme of concrete = 1m^3
b. volume of cement = ( mass of cement/ specific gravity of cement)* 1/100
= (270/3.15)*1/1000
= 0.086m^3
c. volume of flyash = ( mass of water/ specific gravity of flyash)*1/100
= (115/2.2)*1/1000
= 0.052m^3
d. volume of water = (mass of water / specific gravity of water) *1/100
= (140/1)*1/100
= 0.140m^3
e. volume of chemical admixture
= (mass of admixture /specific gravity of admixture)*1/100
= (7.6/1.14)*1/1000
= 0.006m^3
f.volume of aggregate = a-(b+c+d+e)
= 1-(0.086+0.052+0.140+0.006)
= 0.716m^3
g. Mass of coarse aggregate
= f*volume of coarse aggregate* specific gravity of coarse aggregate * 1000
= 0.716*0.576*2.74*1000
= 1130kg/m^3
h. Mass of fine aggregate = f* volume of fine aggregate *specific gravity of fine aggregate*1000
= 0.716*0.424*2.74*1000
= 831kg/m^3
step:9
Mix proportion
cement = 270 kg/m^3
flyash = 115 kg/m^3
water = 140 kg/m^3
fine aggregate = 831 kg/m^3
coarse aggregate = 1130 kg/m^3
chemical admixture = 7 kg/m^3
water cement ratio = 0.364
MIX RATIO 1:2.15: 2.94
step:10
The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump on trail. the mix proportion shall be reworked for the actual water content and checked for durability requirements
step: 11
Two or more trails having variation of 10% of water -cement ratio in clause 10 (step 10) shall be carried out and graph between three water-cement ratios and corresponding strengths shall be plotted to work out the mix proportions for the given traget strength shall be plotted to work out the mix proportions for the given traget strength for feild trails. however durability shall be met.
RESULT:-
The mix design for M 35 grade of concrete with flyash is 1:2.15:2.94
II. Mix design of M50 grade concrete:-
AIM:- Mix design of M50 grade concrete
PROCEDURE:-
Step:1
stipulation for proportioning
- Grade designation:M50
- Type of cement: opc grade 43 conforming to IS 8112
- Maximum nominal size of aggregate : 20mm
- Minimum cement content:320 kg/m^3
- Maximum water-cement ratio: 450 kg/m^3
- chemical admixture type : super platicizer.
step:2
Test data for materials
- cement used:opc 43 grade confirming to IS 8112
- specific gravity of cement :3.15
- chemical admixture: superplasticizer conforming to IS 9103
- specific gravity of: coarse aggregate 2.74 , fine aggregate: 2.74
- water absorbtion: coarse aggregate: 0.5% , fine aggregate : 1%
- Free surface moisture : coarse aggregate:nil, fine aggregate: nil
- seive analysis : coarse aggregate, fine aggregate : conforming to grading zone 1 of table 4 IS 383.
step:3
To find traget mean strength for proportioning
Target mean strength, f'ck= fck+1.65s
= 50+1.65*5
= 58.25n/m^2
fck = characteristic strength
s = standrad deviation
step:4
selection of water cement ratio
From table : 5 of IS 456-2000 by exposure condition
Here severe condition is considered
maximum water- cement ratio = 0.45
Based on experince water-cement ratio =0.4
0.4<0.45 hence ok.
step 5
Selection of water content
Maximum water content for 20mm aggregate =186 litres ( table 2of IS 1026:2009) for 25mm to 50mm slump range
For 100mm slump= 186+(6/100)*186
= 197 litres
As superplaticizer is used, the water content reduction of 29% is achived with plastizer
Hence arrived water content = 197*0.71
= 140 litres
step:6
calculation of cement content:
water-cement ratio =0.4
cement content = 140/0.4
= 350kg/m^3
in table 5 of IS 456-2000, the cement content for severe exposure =320kg/m^3
350kg/m^3>320kg/m^3 hence ok
step:7
Proportion of volume of coarse aggregate and fine aggregate content:
From table 3 of IS 1026:2009 , volume of coarse aggregate corresponding to 20mm size aggregate and fine aggregate (zone 1) for water -cement ratio is 0.4
Therfore the volume of coarse aggregate needs to be incresed to decresed the fine aggregate content.
ratio is lowered by 0.1, the proportion of volume of coarse aggregate is incresed by 0.02 (at the rate of +/- 0.01 for every +/- 0.05 change in water-cement ratio)
Hence the corrected value of coarse aggregate for water cement ratio= 0.64
For pumpable concrete these are reduced by 10%
volume of fine aggregate = 1-0.576
= 0.424
volume of coarse aggregate = 0.64*-0.9
= 0.576
step:8
mix calculations:
Mix calculation per unit volume of concrete
a. voulme of concrete = 1m^3
b. volume of cement = ( mass of cement/ specific gravity of cement)* 1/100
= (350/3.15)*1/1000
= 0.111m^3
c. volume of water = (mass of water / specific gravity of water) *1/100
= (140/1)*1/100
= 0.140m^3
d. volume of chemical admixture
= (mass of admixture /specific gravity of admixture)*1/100
= (7.6/1.14)*1/1000
= 0.006m^3
e.volume of aggregate = a-(b+c+d+e)
= 1-(0.111+0.140+0.006)
= 0.743m^3
f. Mass of coarse aggregate
= f*volume of coarse aggregate* specific gravity of coarse aggregate * 1000
= 0.743*0.576*2.74*1000
= 1173kg/m^3
g. Mass of fine aggregate = f* volume of fine aggregate *specific gravity of fine aggregate*1000
= 0.743*0.424*2.74*1000
= 863kg/m^3
step:9
Mix proportion
cement = 350kg/m^3
water = 140 kg/m^3
fine aggregate = 863 kg/m^3
coarse aggregate = 1173 kg/m^3
chemical admixture = 7 kg/m^3
water cement ratio = 0.4
MIX RATIO 1:2.46:3.35
step:10
The slump shall be measured and the water content and dosage of admixture shall be adjusted for achieving the required slump on trail. the mix proportion shall be reworked for the actual water content and checked for durability requirements
step: 11
Two or more trails having variation of 10% of water -cement ratio in clause 10 (step 10) shall be carried out and graph between three water-cement ratios and corresponding strengths shall be plotted to work out the mix proportions for the given traget strength shall be plotted to work out the mix proportions for the given traget strength for feild trails. however durability shall be met.
RESULT:- The mix ratio for M50 grade concrete is 1:2.46:3.35