Numerical problem on concrete mix design by is 10262(2009) method

Design of M25 grade concrete mix as per IS:10262-2009, Concrete mix proportioning guidelines with given design stipulations

1. Subject: Concrete Technology
Numerical Problem on Concrete Mix
Design by IS:10262(2009) method
by
Dnyaneshwar. D. MoreDnyaneshwar. D. More
(Assistant Professor)DEPARTMENT OF CIVIL ENGINEERING
SanjivaniRural Education Society’s
SANJIVANI COLLEGE OF ENGINEERING, KOPARGAON –423 603
SAVITRIBAI PHULE PUNE UNIVERSITY, PUNE

2. Problem
DesignofM25gradeconcretemixasperIS:10262-
2009,Concretemixproportioningguidelines
1.DesignStipulationsForProportioning
i.Gradedesignation:M25
ii.Typeofcement:OPC43gradeconfirmingtoIS8112ii.Typeofcement:OPC43gradeconfirmingtoIS8112
iii.MaximumnominalsizeofC.A.:20mm
iv.Minimumcementcontent:320Kg/m
3
v.Maximumwatercementratio:0.55
vi.Workability:75mm(slump)

3. vii. Exposure condition : Mild
viii. Degree of supervision : Good
ix. Type of aggregate : Crushed angular aggregate
x. Maximum cement content : 450 kg/m
3
xi. Chemical admixture : Not recommended
2. Test Data For Materials2. Test Data For Materials
p) Cement used : OPC 43 grade confirming to IS 8112
q) Specific gravity of cement : 3.15
r) Specific gravity of (SSD Condition):
i.Coarse aggregate : 2.68
ii.Fine aggregate : 2.65

4. s) Water absorption:
i.Coarse aggregate : 0.6 percent
ii.Fine aggregate : 1.0 percent
t) Free (surface) moisture:
i.Coarse aggregate : Nili.Coarse aggregate : Nil
ii.Fine aggregate : Nil
u) Sieve analysis result (Conforming IS: 383)
i.Coarse aggregate : Table 2 of IS: 383
ii.Fine aggregate : Zone I of IS: 383

5. 3.TargetStrengthForMixProportioning
Fck=fck+1.65xS
Where,
Fck=Targetaveragecompressivestrengthat28days,
fck=Characteristiccompressivestrengthat28days,fck=Characteristiccompressivestrengthat28days,
S=Standarddeviation
FromTable1standarddeviation,S=4N/mm
2
Therefore,Targetstrength,
Fck=25+1.65x4=31.60N/mm
2

6. 4.SelectionofWaterCementRatio
FromTable5ofIS:456-2000,maximumwatercement
ratio=0.55(Mildexposure),
adoptwatercementratioas0.50.
So,0.5<0.55,henceok.
5.SelectionofWaterContent5.SelectionofWaterContent
From Table-2, IS:10262, maximum water content =
186 liters (for 25mm to 50mm slump range and for 20
mm aggregates)
Estimated water content for 75 mm slump = 186
+3/100x186=191.6liters

7. 6. Calculation of Cement Content
Water cement ratio = 0.50
Cement content = W.C./w-c ratio=191.6/0.5=383 kg/m3 i.e.
> 320 kg/m3
also, mini. cement content as per Table 5 of
IS: 456 for mild exposure condition =300 kg/m
3
and
also < 450 kg/m
3
Hence, Ok.
7.ProportionofVolumeofCoarseAggregateandFine7.ProportionofVolumeofCoarseAggregateandFine
AggregateContent:
From Table 3, of IS:10262 corresponding to 20 mm size
aggregate and fine aggregate (Zone I) for water-cement
ratio of 0.50
volume of coarse aggregate =0.60

8. 8.MixCalculations
Themixcalculationsperunitvolumeofconcreteshall
beas:
a)Volumeofconcrete=1m
3
b)Volumeofcement=[383.16/3.15]x[1/1000]
3
=0.122m
3
c)Volumeofwater=[192/1]x[1/1000]=0.192m
3
d)Volumeofallinaggregates=(a)–(b)–(c)
=1–0.122–0.192
=0.686m
3

9. e)Massofcoarse
aggregates=(d)xVolumeofCAxsp.gravityofCA
=0.686x0.6x2.68x1000
=1103kg
f)Massoff)Massof
fineaggregates=(d)xVol.ofFAxsp.gravityofFA
=0.686x0.4x2.65x1000
=727kg

10. 9.EstimatedquantitiesforTrialMix1(SSDCondition)
Cement=383kg/m
3Water=191.6kg/m
3
Fineaggregate=727kg/m
3
Coarseaggregates=1103kg/m
3
Watercementratio=0.50Watercementratio=0.50
Yield=(383+191.6+727+1103)=2404.6kg/m
3
10.Mix Proportions For Trial Number 1 (SSD)
w/c=0.50; Cement
:
Fine Agg.
:
Coarse agg.
1
:
1.89
:
2.88

11. 11.Correctionforfreesurfacemoistureandwater
absorption(AggregatesotherthanSSD):
AsperIS:10262aggregatesshallbeusedinSSDcondition.
Ifno,allowanceshallbemadeforthefree(surface)
moisturecontributedbythefineandcoarseaggregates.
iftheaggregatesaredry,theamountofmixingwatershall
beincreasedbyanamountequaltothemoisturelikelytobeincreasedbyanamountequaltothemoisturelikelyto
beabsorbedbytheaggregates.
Necessaryadjustmentsarealsorequiredtobemadein
massofaggregates.
Providedthesurfacewaterandpercentagewater
absorptionofaggregatesshallbedeterminedaccordingto
IS2386afterthatthewillbecheckbytrialmix/batches.

12. Correctionforfreesurfacemoistureandwaterabsorption
(AggregatesotherthanSSD):
(In our case the coarse and fine aggregates are in dry condition as
water absorption is given)
a)Fine Aggregate (Dry) = (Mass of SSD F.A.) / {1+((water absorp. by F.A.)/100)}
=
727 /{1+((1)/100)}
= 719.802 kg/m
3
b)Coarse Aggregate (Dry) = (Mass of SSD C.A.) /{1+((water absorp. C.A.)/100)} b)Coarse Aggregate (Dry) = (Mass of SSD C.A.) /{1+((water absorp. C.A.)/100)}
= 1103 /{1+((0.6)/100)}
=1096.42 kg/m3
c)The extra water to be added for absorption:
Fine Aggregate = (Mass of FA in SSD condition –Mass of FA in dry condition)
=727–719.802
=7.2kg
coarse Aggregate = (Mass of CA in SSD condition –Mass of CA in dry condition)
=1103–1096.42
=6.58kg

13. c)Theextrawatertobeadded
forabsorption=waterabsorbedbyF.A.+waterabsorbedbyC.A.
=7.2+6.58
=13.78kg
Estimatedwatercontentwillbe=watercontentbeforecorrection+water
tobeaddedforabsorption
=191.6+13.78
=205.38kg
12.FinalEstimatedquantities:ForTrialmixNumber112.FinalEstimatedquantities:ForTrialmixNumber1
Cement=383kg/m3
Water=205.38kg/m3
Fineaggregate=719.802kg/m3
Coarseaggregates=1096.42kg/m3
Watercementratio=0.536
Yield=(383+205.38+719.802+1096.42)=2404.602kg/m3

14. 13. FinalMix Proportions For Trial Number 1 (SSD)
w/c=0.536;
Cement
:
Fine Agg.
:
Coarse agg.
1
:
1.879
:
2.863
TrialBatchesorMixes:
ThecalculatedmixproportionsshallbecheckedbyThecalculatedmixproportionsshallbecheckedby
meansoftrialbatches.
Quantityofconcrete(materials)foreachtrialshall
beenoughforcastingatleastthree150mmsize
cubesandtocarryoutworkabilitytestaccordingto
IS:1199.

15. TrialMix1:shouldbecheckedforworkabilityand
freedomfromsegregationandBleedingandits
finishingproperty.
TrialMix2:IfthemeasuredworkabilityTrialmix1
differentfromthestipulatedvalue,thewaterand/or
admixturecontentshallbeadjustedsuitably.Withthisadmixturecontentshallbeadjustedsuitably.Withthis
adjustment,themixproportionshallberecalculated
keepingthefreewater-cementratioatthepre-
selectedvalue.
TrialMix3:changewater-cementratioby+10%of
preselectedorfinallyreachedvalueandrecalculate
mixproportions.

16. TrialMix4:changewater-cementratioby-10%of
preselectedorfinallyreachedvalueandrecalculate
mixproportions.
Testingfortrialmixnumbers2,3,4aredone
simultaneously.
Thesetestsnormallyprovidesufficientinformation,Thesetestsnormallyprovidesufficientinformation,
includingtherelationshipbetweencompressive
strengthandwater-cementratio,fromwhichthe
mixproportionsforfieldtrialsmaybearrived.

17. Trial mix No.1234
Final mix
proportions
Qty. per bag
of cement (kg)IngredientQuantity per cu. meter
Water-cement ratio
Cement .
Water
C.A.-I ( %)
C.A.-II ( %)
F.A.
W
Mix Proportions Summary
W
O
R
K
ability
Slump(mm)
C.F.
Flow Table
Visual Observations
Comp.
Strength
(N/mm
2
)
7
Days
28
Days
Remark
17