Project on Concrete Mix Design for various grades of Concrete
Mix design for M35 grade of concerete with fly ash------
Step 1 ---
stipulations for proportining---
a.grade designation =M35
b.cement opc 43 grade Is 8112
c.type of mineral admixture;fly ash ;conforming is 3812
d.maximum nominal size of aggregate=20mm
.e. min. cement content ; 320 kg\m^3 Is code456:2000 based on exposure condtion
f.maximum water cement ratio =.45 [Is 456 :2000] exposure condition
g.workability =100 mm slump for pumpable concerete
h.Exposure condition :severe
i:type of aggregates: crushed angular .
j.maximum cement content=450 kg/m^3.
k.chemical admixture type: superplaticizer
step-2.
Test data for materials ----
a.cement used=opc 43 grade confirming Is 8112
b.specific gravity of cement =3.15
c. fly ash =confirming is 3812 part 1
d.specific gravity of flyash=2.2
e.chemical admixture=.6%-- is 9103
f.specific gravity--
coarse aggregate=2.74
fine aggregate:2.74
g.water absorption ---test is 2386
C.A.:0.5%
F.A.: 1%
h.free surface moisture--- nil for C.A. and F.A.
i.sieve analysis---
coarse aggregate :--
fine aggregate:conforming to grading zone1 of table 4 is 383.
Step 3---find target mean strength f' ck=fck +1.65s
=35+1.65*5=43.25N/mm^2
s=standard deviation
Step-4
selection water cement ratio---
maximum water cement ratio =0.45 ; - is code 456:2000 severe condition
- exprience water cement ratio =0.4
- 0.40<.45, hense ok
step-5
calculation of water cement ratio--for 20 mm agg. maximum water content =186 liter
this range is 25 to 50 mm slump
for 100 mm slump
=186+186*6/100=197 liters
when superplatizer are used ;according to based on trial this value redused up to 30% and 29%.
we take=29%
hense arrivwd water content=197*0.71=140 liter.
step6;
calculation on cement content--
Water cement ratio =.40
cementious material[cement +flyash]=140/.4=350kg/m^3
is code 456:2000
cement content=320kg/m^3
we get 350 kg/m^3 >320 kg/m^3 ok.
for fly ash----
1. percentage of fly ash need , depend upon project requrement, qulity of material.
2.increase cementeious material content =10% = 350*1.1=385kg/m^3
this is based on exprience and trial so
3.water content=140 kgm^3
4 .water cement ratio =140/385=.364
fly ash 30% total cementious material=115kg/m^3
cement =385-115=270kg/m^3
saving of cement while using fly ash=350-270=80 kg/m^3
fly ash utilize=115kg/m^3
step7----proportion of coarse.aggregate. and f.a.---
take in code =20mm size aggregate ,fine aggregate zone one w/c=0.6
when water cement ration is lowered by .1, proportion of volume of coarse aggregate is increased by .02
hense corrected value of C.A. for W/C=0.64
for pumpable concerete this value reduced =10%
volume of C.A.=.64*.9=.576
volume of fine aggregate =1-.576 =.424
Step-8 Mix calculation=
a. volume of concerete=1 m^3
b. volume of cement=[mass of cement /specific gravity of cement]*1/1000
=[270/3.15]*1/1000=0.086 m^3
c.volume of flyash =[mass of flyash/specific gravity of fly ash]*1/1000
=[270/3.15]*1/1000 =.052m^3
d.volume of water=[140/1]*1/1000=0.140m^3
e.volume of chemical admixer=[7.6/1.14]*1/1000=.006m^3
f.volume of aggregate=a-[b+c+d+e]
1-[.086+.052+.140+.006]=0.716 m^3
g.mass of coarse aggregate=f*voiume of C.A.*specific gravity of coarse aggregate*1000
=.716*.576*2.74*1000=1130 kg/m^3
h. mass of fine aggregate=f*vol. of fine aggregate*specific gravity of fine aggregate*1000
=.0716*.424.*2.74*1000 =831 kg/m^3
step9--- adopt -mix proportion --
cement =270 kg/m^3
fly ash=115 kgm^3
water=140 kg/m^3
w/c ratio=0.364
fine aggregate =831 kg/m^3
coarse aggregate =1130 kg /m^3
chemical admixture =7 kg/m^3
final mix ratio 1:2.15:2.94
step10--
slump shall be mesure and water content also mesure . than doases of admixture should be adjust for achiveing requred slump on trial .
-mix proportion shall be rewored for actual water content.
-and also cheked for durability requrement.
step-11---
two or more trials check variation 10% of W/C ratio in step 10 ,carried out
and a graph between 3, w/c ratio and
corresponding strength shall be plotted to work out the mix proportion for the given target strength for field trials.
however durability shall be met.
Result --- The mix design M35 grade of concerete with fly ash = 1:2.15:2.94
Aim----mix design of M50 grade of conceret--
step 1--stipulation forproportiong ---
1. grade =m50
2. cement =opc. 43 is 8112
3. maximum nominal size of aggregate-20mm
4.minimum cement content=320 kg/m^3
5. 450 kg/m^3= maximum cement content -
6. maximum w/c=.45 is 456 :2000
7.workability =100 mm
slump value of pumpable concerete
8. concerete placing methode =pumping
9. crushed angular agg.
10.severe exposure condition
11. admixer =superplasticizer
step 2-
test data of materials--
cement =opc 43 grade
specific gravity of cement =3.15
specific gravity
a. coarse aggregates =2.74
b. fine aggregate=2.74
-water absorptin
coarse aggregate =0.5%
fine aggregate =1%
-free surface moisture-nil in both fine and coarse aggregate
-sieve -fine aggregate -grading zone 1 table4 IS 383
Step 3---
target mean strength f'ck=fck+1.65s
=50+1.65*5 =58.25n/mm^2
step-4
severe condition W/C ratio=0.45 [table 5-IS 456 :2000]
exprienced water cement ratio =0.40
0.45>.40 ok
step 5--
water content ---for 20 mm aggregates ,maximum water content =186 liter
for slump 25 to 50 mm
we take 100 mm slump than = 186+186*6/100 =197 liter
when used super plasticizer this value reduced up to 30%
take 29%
so, 197*.71 =140 liter
step 6--
cement content =140/0.40=350 kg/m^3
in code IS 456: 2000 cement content for severe exposure condition =320 kgm^3
350 kg/m^3 > 320 kg/m^3
step7--
proportion of volume of C.A. corresponding to 20 mm size aggregate and fine agg. [zone 1] water cement ratio ----=0.60
if water cement ratio is lower by .1, than volume of coarse aggregates is increased by 0.02
hense corrected value of coarse aggregates for the water cement ratio =0.64
for pumpable concerete these are reduced to =10%
volume of coarse aggregates =.64*.9=0.576
volume of fine aggregate=1-0.576 =0.424
step 8--Mix calculation --- a] volume of concerete= 1m^3
b]volume of cement =[350/3.15]*1/1000
=0.111 m^3
c]. volume of water =[140/1]*1/1000
0.140 m^3
d] volume of chemical admixture =[7.6/1.145]*1/1000
=.006 m^3
e] volume of aggregates [both fine and coarse ] = a-[b+c +d]
= 1-[.111+.140+.006]
=0.743 m^3
f] mass of coarse aggregate =e * vol. of coarse aggreegate*specific gravity of C.A. *1000
0.743*.576*2.74*1000
=1173 kg/m^3
g]
mass of fine aggregate =exvol. of fine aggxspecific gravity of F.A. x1000
=0.743x0.424*2.74*1000=863 kg/m^3
step 9- mix proportion --cement =350 kg/m^3
water =140 kg /m^3
fine aggregate= 863 kg/m^3
coarse agg. =1173 kg/m^3
chemical admixtures =7 kg/m^3
water cement ratio =0.40
Mix ratio =1:2.46:3.35
step 10--- slump shall be mesured and
----water content and doase of admixure shall be adjust -for achiveing required slump on trial .
--mix proportion shall be reworked for actual water content and check for durability.requirment.
step 11---two or more trials do and having variation =10% of water cement ratio
-shall be carried out and a graph between 3 water cement ratios
-and corresponding strength shall be plot to work out mix proportion for given target strenth for field trials.
however durability shall be met.
Result Mix ratios for M50 grade concerete =1:2.46:3.35 .