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 .