Project on Concrete Mix Design for various grades of Concrete
- concrete mix design :-
concrete is a complex material and has the right mix of contituents of concrete which if not done properly and will have adverse effect on the propertites of concrete.
concrete mix design is a systematic process of choosing economical relative proportion of various ingredients from available materials that gives the concrete of desired workability.
the process of selecting suitable ingredients for producing concrete required strength,durability and workabilty as economical as possible is know as concrete mix design.
the compressive strength of concrete depends upon the quality and quantity of cement,water and aggregates.
it also depends on the mixing,batching,placing and curing.
- calculate the concrete mix design for M35 grade concrete with fly ash :-
a) Grade designation = M35 grade
b) Type of cement =OPC 43 grade cement
c) Type of mineral admixture = fly ash
d) Maximum nominal size of aggregate = 20MM
e) Minimum cement content =300KG/M^3
f) Maximum water-cement ratio =0.50
g) Workability =100 MM
h) Exposure condition =moderate
j) Method of concrete placing =pumping
k) Degree ofsupervision =good
m) Type of aggregate =crushed angular aggregates
n) Maximum cement (OPC) content =450 KG/M^3
p) Chemical admixture type =superplastisizer
TEST DATA FOR MATERIALS
a) Cement used = OPC 43 grade cement
b) Specific gravity of cement = 3.15
c) Fly ash = conforming to IS 3182
d) Specific gravity of fly ash = 2.2
e) Chemical admixture =superplastisizer
f) Specific gravity of: -
1) Coarse aggregate =2.74
2) Fine aggregate =2.74
g) Water absorption:-
1) Coarse aggregate =0.5%
2) Fine aggregate =1%
h) Free (surface) moisture: -
1) Coarse aggregate =nil
2) Fine aggregate =nil
- target strength for mix proportion :-
f'ck = fck + 1.65 (s)
= 35 + 1.65*5
= 43.25 N/MM^2
- selection of water-cement ratio :-
from table 5 of IS 456:2000 for moderate exposure maximum water-cement ratio =0.50
based on experience,adopt water-cement ratio as 0.45
0.45<0.50, hence ok.
- selection of water content :-
from table 2 of IS 10262:2009 maximum water content for 20MM aggregates=186 litre(25mm to 50mm slump range)
estimated water content for 100mm slump=186 + 6/100 * 186 = 197 litre.
as superplasticizer is used the water content can be reduced upto 30% based on trials water content reductionof 25% is achieved with plasticizer.hence the achivied water-content= 197-25/100*197 = 147.5=148 litre
- calculation of cement content :-
cementitous materials cement +fly ash content = 148/0.45 = 328.88= 329 KG/M^3
from table 5 of IS 456:2000 minimum cement content for severe exposure conditions =300 KG/M^3
300 KG/M^3 < 329 KG/M^3
- now to proportion a mix containing fly ash the following steps are used:-
cementitious material content = 329 + 10/100 * 329 = 361.9 = 362 KG/M^3
water conents =148 KG/M^3
water cement ratio = 148/362
= 0.408
fly ash @30% total cementitious material content :-
= 362*30/100
= 109 KG/M^3
cement (OPC) = 362 -109
= 253 KG/M^3
saving of cement using fly ash :-
= 329 - 253
= 76 KG/M^3
fly ash being utilized = 109 KG/M^3
- proportion of volume of coarse aggregates and fine aggregates content :-
from table 3 of IS 10262:2009 volume of coarse aggregates and fine aggregates (zone I) for water cement ratio of 0.5=0.6
in the present case water-cement ratio is 0.45.
therefore,the volume of coarse aggregates need to be increased to decrase the fine aggregates content.
therefore,corrected volume of coarse aggregates for water cement ratio of 0.45 = 0.61.
for pumpable concrete these values are reduced by 10%
volume of coarse aggregates = 0.61 * 10/100 = 0.61 - 0.061 = 0.54
volume of fine aggregates = 1- 0.549 = 0.45
- mix calculations :-
1.) volume of concrete = 1M^3
2.)volume of cement :-
= mass of cement/ specific gravity of cement * 1 /1000
= 253 / 3.15 * 1 / 1000
= 0.080 M^3
3.)volume of fly ash :-
= mass of fly ash / specific gravity of cement * 1 / 1000
= 109 / 2.2 * 1 / 1000
= 0.049 M^3
4.)volume of water :-
= mass of water / sp.gravity of water * 1/1000
= 148 / 1 * 1 / 1000
= 0.148
5.)volume of chemical admixture :-
= mass of admixture / sp.gravity of admixture * 1 / 1000
= (362*2/100) / 1.145 * 1 / 1000
= 0.006 M^3
6.)volume of coarse and fine aggregates :-
= [ 1 - ( 2+3+4+5) ]
= [1 - ( 0.080 + 0.049 + 0.148 + 0.006 ) ]
= 0.717 M^3
7.)mass of coarse aggregates :-
= 0.717 * 0.54 * 2.74 * 1000
= 1060 KG/M^3
8.)mass of fine aggregates :-
= 0.717 * 0.45 * 2.74 * 1000
= 885 KG/M^3
- mix proportions :-
cement = 253 KG/M^3
fly ash = 109 KG/M^3
water = 148 KG/M^3
fine aggregates = 885 KG/M^3
coarse aggregates = 1060 KG/M^3
admixture = 7.24 KG/M^3
water-cement ratio = 0.408
- mix ratio :- 1 : 2.44 : 2.92
- calculate the concrete mix design for M50 grade concrete :-
a) Grade designation = M50 grade
b) Type of cement =OPC 53 grade cement
c) Type of mineral admixture = none
d) Maximum nominal size of aggregate = 20MM
e) Minimum cement content =320 KG/M^3
f) Maximum water-cement ratio =0.45
g) Workability =75 MM
h) Exposure condition =severe
j) Method of concrete placing =pumping
k) Degree ofsupervision =good
m) Type of aggregate =crushed angular aggregates
n) Maximum cement (OPC) content =450 KG/M^3
p) Chemical admixture type =superplastisizer
TEST DATA FOR MATERIALS
a) Cement used = OPC 43 grade cement
b) Specific gravity of cement = 3.15
c) Fly ash = none
d) Specific gravity of fly ash = none
e) Chemical admixture =superplastisizer
f) Specific gravity of: -
1) Coarse aggregate =2.68
2) Fine aggregate =2.85
g) Water absorption:-
1) Coarse aggregate =0.5%
2) Fine aggregate =1%
h) Free (surface) moisture: -
1) Coarse aggregate =nil
2) Fine aggregate =nil
- target strength for mix proportion :-
f'ck = fck + 1.65 (s)
= 50 + 1.65*5
= 58.25 N/MM^2
- selection of water-cement ratio :-
from table 5 of IS 456:2000 for moderate exposure maximum water-cement ratio =0.45
based on experience,adopt water-cement ratio as 0.40
0.40 < 0.45, hence ok.
- selection of water content :-
from table 2 of IS 10262:2009 maximum water content for 20MM aggregates=186 litre(25mm to 50mm slump range)
estimated water content for 100mm slump=186 + 3/100 * 186 = 192 litre.
as superplasticizer is used the water content can be reduced upto 30% based on trials water content reductionof 25% is achieved with plasticizer.hence the achivied water-content= 192-(25 / 100 * 192) =144 litre
- calculation of cement content :-
cementitous materials cement +fly ash content = 144 / 0.40 = 360 KG/M^3
from table 5 of IS 456:2000 minimum cement content for severe exposure conditions =300 KG/M^3
320 KG/M^3 < 360 KG/M^3
- proportion of volume of coarse aggregates and fine aggregates content :-
from table 3 of IS 10262:2009 volume of coarse aggregates and fine aggregates (zone I) for water cement ratio of 0.5=0.6
in the present case water-cement ratio is 0.40.
therefore,the volume of coarse aggregates need to be increased to decrase the fine aggregates content.
therefore,corrected volume of coarse aggregates for water cement ratio of 0.40 = 0.62.
for pumpable concrete these values are reduced by 10%
volume of coarse aggregates = 0.62 * 10/100 = 0.62 - 0.062 = 0.56
volume of fine aggregates = 1- 0.56 = 0.44
- mix calculations :-
1.) volume of concrete = 1M^3
2.)volume of cement :-
= mass of cement/ specific gravity of cement * 1 /1000
= 360 / 3.15 * 1 / 1000
= 0.114 M^3
3.)volume of water :-
= mass of water / sp.gravity of water * 1/1000
= 144 / 1 * 1 / 1000
= 0.144
4.)volume of chemical admixture :-
= mass of admixture / sp.gravity of admixture * 1 / 1000
= (360*2/100) / 1.145 * 1 / 1000
= 0.006 M^3
5.)volume of coarse and fine aggregates :-
= [ 1 - ( 2+3+4) ]
= [1 - ( 0.114 + 0.144 + 0.006 ) ]
= 0.736 M^3
6.)mass of coarse aggregates :-
= 0.736 * 0.56 * 2.68 * 1000
= 1105 KG/M^3
7.)mass of fine aggregates :-
= 0.736 * 0.44 * 2.85 * 1000
= 922 KG/M^3
- mix proportions :-
cement = 360 KG/M^3
water = 144 KG/M^3
fine aggregates = 922 KG/M^3
coarse aggregates = 1105 KG/M^3
admixture = 7.2 KG/M^3
water-cement ratio = 0.4
- mix ratio :- 1 : 2.56 : 3.06