Project on Concrete Mix Design for various grades of Concrete
AIM: Calculate the Concrete Mix Design for M35 grade concrete with fly ash.
INTRUDUCTION :Concrete ix design systemetic process of coosig economical relative prapotion of various ingredients from availabile material that gives the concrete of desired workabilty.the process of selecting suitabile ingredients for producing concrete of required strength durabuility and workability as economical as passibile is known as concrete mix design.
OBJECTIVE: Now we find out the designmix ratio for the M35 grade concrete with flyash.
EQUVATION REQUIRE :
TARGET MEAN STRENGTH:
The target means strength for specified characteristic cube strength @ 28 days,
f’ck = fck + 1.65 s
where
f’ck is target average compressive strength at 28
fck is characteristics compressive strength @ 28 days, and
s is Standard Deviation values (suggested values available in Table 1,
Page No. 2 of IS 10262 – 2009)
CEMENT CONTENT: With quantity of water and water-cement ratio, cement content can be calculated.
Quantity of water
Cement content = --------------------------
Water-cement ratio
MIX CALLUCULATION
- volume of concreate = 1m^3
- volume of cement =mass of cement /specific gravity of cement x 1/1000
- volume of fly ash =(mass of flyash /specific gravity of fly ash)x(1/1000)
- volume of water=mass of water /specific gravity of water x 1/1000
- volume of chemical admixture =mass of chemical admixture/ specific gravity of admixturex1/1000
- volume of aggregate (FA&CA)=(a-(b+c+d+e))
- mass of coarse aggregate = f x volume of corse aggregate x specific gravity of coarse aggregate x 1000
- mass of fine aggregate = f x volume of fine aggregate x specific gravity of fine aggregate x 1000
IS-CODES FOR DESIGN MIX CACULATION:
1. IS 12269 – 1987, ‘Specification for 53 Grade Ordinary Portland Cement’
2. IS 2386 (Part I to VIII) – 1963, ‘Method of test for aggregates for Concrete’
3. IS 383 – 1970, ‘Specification for Coarse and Fine aggregate from natural
sources’
4. IS 10262 – 2009, ‘Concrete Mix Proportioning – Guidelines’ (First Revision)
5. IS 516 – 1959, ‘Method of test for Strength of Concrete’
6. IS SP 23 – 1982, ‘Hand Book of Concrete Mixes’
7. IS 456 – 2000, ‘Code of Practice for Plain and Reinforced Concrete
DATA COLLECTION:
Grade of designation : M35
type of cement : OPC 43
Type of admixture : flyash
max nominal size of aggregate : 20mm
minimum cement content : 320( table no 5)
max water cement ratio =0.45 as per taile no .5 exposure condition
workability =100mm
exposutre condition =seveare
method of concreate placeing = pumping
degree of supervission = good
type of aggregate =crushed angular aggregate
max cement content =0.46
chemical admixture type = superplasticizers
TESTS FOR MATERIALS:
cement used :OPC 43
specific gravity of cement : 3.15
chemical admixture : superplasticizers
specific gravity coarse aggregate = 2.74
specific gravity of fine aggregate = 2.74
Free surface moisture of course aggregate = nill
Free surface moisture of fine aggregate = nill
water absorption of course aggregate =0.5%
water absorption of fine aggregate = 1.0%
TARGET MEAN STRENGTH:
The target means strength for specified characteristic cube strength @ 28 days,
f’ck = fck + 1.65 s =35+1.65 X 5 =43.25N/mm^2
where
f’ck is target average compressive strength at 28
fck is characteristics compressive strength @ 28 days, and
s is Standard Deviation values = 5 N/mm^2 (suggested values available in Table 1,
Page No. 2 of IS 10262 – 2009)
Target mean strength = 43.25N/mm^2
SELECTION OF WATER CEMENT RATIO:
From Table 2, for Mild exposure condition maximum water-cement ratio is 0.55
Based on experience adopt water-cement ratio 0.50
0.50<0.55, hence, o.k.
Selection of Water content:
From Table 3, Maximum water content is 186 kg/m3 (for a slump of 25 to 50mm)
Water content can be increased by 3% for every 25 mm increase of slump.
Hence, for our required 100 mm slump
water content =186+(6/100)x186=197 lit
(NOTE: If super plastisizer used water content will reduce uptp to 20%) =197x0.8=158 lit
water content required = 158 lits
SELECTION FLY ASH AND CEMENT CONTNT REQUIRED:
Water cement ratio = 0.4
cemetious material (cement +fly ash) cement content =158/0.4 =359 kg/mm^3
from tabile no.5 of IS 456 minimum cement content for ' severe' exposure condition =340kg/mm^3
hence 350 kg/mm^3 > 340 kg/mm^3 OK
now to proportion a mix contained fly ash the following steps are suggested
cementitious material content =359x 1.10 = 395 kg/mm^3
water content =158 lit
water/cement ratio =158/395 = 0.4
fly ash @ 30% total cementitious content =359x 30% =118 kg/m^3
cement =395-118 =277 kg/mm^3
saving of cement while useing flyash =395-277 =73kg/mm^3
fly ash being utilized =118 kg/m^3
arrived values of cementitious material ,cement and fly ash is 395 kg/mm^3,277 kg/mm^3 and 118 kg/m^3
propotion of volume of coarse aggregate and fine aggregate content from table 3 of IS 10262:2009 volume of course aggregate corresponding to 20mm size aggregate and fine aggregate ( zone 1) for water content =0.6
In present case the W/C RATIO = 0.4
there fore the volume of coarse aggregate needs to be incressed to decrease the fine aggregate content
as water cement ratio is lower by 0.10 the propotion 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 )
there fore corrected volume of coarse aggregate for the w/c ratio of 0.04 = 0.62
for pumpable concrete there values and reduced by 10%
there fore volume of coarse aggregate =0.62x0.9 =0.568
volume of fine aggeregate =1-0.568 =0.431
Volume of coarse aggregate and fine aggregate =0.568 & 0.431
MIX CALLUCULATION
- volume of concreate = 1m^3
- volume of cement =mass of cement /specific gravity of cement x 1/1000 = (277/3.15)x(1/1000)=0.087m^3
- volume of fly ash =(mass of flyash /specific gravity of fly ash)x(1/1000) =(118/2.2)x(1/1000) =0.053m^3
- volume of water=mass of water /specific gravity of water x 1/1000 =(158/1)x(1/1000) =0.158m^3
- volume of chemical admixture =mass of chemical admixture/ specific gravity of admixturex1/1000 =(7.6/1.145)x(1/1000)=0.006m^3
- volume of all in aggregate (FA&CA)=(a-(b+c+d+e)) =(1-(0.087+0.053+0.158+0.006))=0.696m^3
- mass of coarse aggregate = f x volume of corse aggregate x specific gravity of coarse aggregate x 1000 = 0.696x0.568x2.74x1000=1077kg/m^3
- mass of fine aggregate = f x volume of fine aggregate x specific gravity of fine aggregate x 1000 =0.696x0.431x2.74x1000=822kg/m^3
ARRRIVED AT THE VOLUES OF COARSE AGGREETE AND FINE AGGREGATE IS 1077kg/mm^3 and 822 kg/mm^3
MIX PRAPOTION FOR TRIAL NUMBER
- CEMENT =277 kg/mm^2
- Flyash = 118 kg/m^2
- water =158 lits
- fine aggregaate =822kg/m^3
- coarse aggregate =1077kg/m^3
- chemical admixture =7.18kg/m^2
- water cement ratio = 0.4
- trial mix =1:2.08:2.72
- =277:822:1077
PART -2 DESIGNMIX OF M50 WITHOUT FLYASH
DATA COLLECTION:
Grade of designation : M35
type of cement :opc 43
Type of admixture : flyash
max nominal size of aggregate : 20mm
minimum cement content : 320( table no 5)
max water cement ratio =0.45 as per taile no .5 exposure condition
workability =100mm
exposutre condition =seveare for rcc
method of concreate placeing = pumping
degree of supervission = good
type of aggregate =crushed angular aggregate
max cement content =450kg/m^3
chemical admixture type = superplasticizers
TESTS FOR MATERIALS:
cement used :OPC 43
specific gravity of cement : 3.15
chemical admixture : superplasticizers
specific gravity coarse aggregate = 2.74
specific gravity of fine aggregate = 2.74
Free surface moisture of course aggregate= nill
Free surface moisture of fine aggregate = nill
water absorption of course aggregate =0.5%
water absorption of fine aggregate = 1.0%
sieve analysis coarse aggregate =conforming to table IS 383
sieve analysis =conforming gradig zones tabile 4 of is 383
TARGET MEAN STRENGTH:
The target means strength for specified characteristic cube strength @ 28 days,
f’ck = fck + 1.65 s =35+1.65 X 5 =43.25N/mm^2
where
f’ck is target average compressive strength at 28
fck is characteristics compressive strength @ 28 days, and
s is Standard Deviation values = 5 N/mm^2 (suggested values available in Table 1,
Page No. 2 of IS 10262 – 2009)
Target mean strength = 43.25N/mm^2
SELECTION OF WATER CEMENT RATIO:
From Table 2, for Mild exposure condition maximum water-cement ratio is 0.4
Based on experience adopt water-cement ratio 0.50
0.4<0.5, hence, o.k.
Selection of Water content:
From Table 3, Maximum water content is 186 kg/m3 (for a slump of 25 to 50mm)
Water content can be increased by 3% for every 25 mm increase of slump.
Hence, for our required 100 mm slump
water content =186+(6/100)x186=197 lit
(NOTE: If super plastisizer used water content will reduce uptp to 20%) =197x0.8=158 lit
water content required = 158 lits
SELECTION FLY ASH AND CEMENT CONTNT REQUIRED:
Water cement ratio = 0.4
cement content =158/0.4 =359 kg/mm^3
from tabile no.5 of IS 456 minimum cement content for ' severe' exposure condition =340kg/mm^3
hence 359 kg/mm^3 > 340 kg/mm^3 OK
arrived values ofcement is 395 kg/mm^3
propotion of volume of coarse aggregate and fine aggregate content from table 3 of IS 10262:2009 volume of course aggregate corresponding to 20mm size aggregate and fine aggregate ( zone 1) for water content =0.6
In present case the W/C RATIO = 0.4
there fore the volume of coarse aggregate needs to be incressed to decrease the fine aggregate content
as water cement ratio is lower by 0.10 the propotion 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 )
there fore corrected volume of coarse aggregate for the w/c ratio of 0.04 = 0.62
for pumpable concrete there values and reduced by 10%
there fore volume of coarse aggregate =0.62x0.9 =0.568
volume of fine aggeregate =1-0.568 =0.431
Volume of coarse aggregate and fine aggregate =0.568 & 0.431
MIX CALLUCULATION
- volume of concreate = 1m^3
- volume of cement =mass of cement /specific gravity of cement x 1/1000 = (277/3.15)x(1/1000)=0.114m^3
- volume of water=mass of water /specific gravity of water x 1/1000 =(158/1)x(1/1000) =0.158m^3
- volume of chemical admixture =mass of chemical admixture/ specific gravity of admixturex1/1000 =(7.6/1.145)x(1/1000)=0.006m^3
- volume of all in aggregate (FA&CA)=(a-(b+c+d+e)) =(1-(0.087+0.053+0.158+0.006))=0.722m^3
- mass of coarse aggregate = f x volume of corse aggregate x specific gravity of coarse aggregate x 1000 = 0.696x0.568x2.74x1000=1123kg/m^3
- mass of fine aggregate = f x volume of fine aggregate x specific gravity of fine aggregate x 1000 =0.696x0.431x2.74x1000=821kg/m^3
ARRRIVED AT THE VOLUES OF COARSE AGGREETE AND FINE AGGREGATE IS 1123kg/mm^3 and 821 kg/mm^3
MIX PRAPOTION FOR TRIAL NUMBER
- CEMENT =359 kg/mm^2
- water =158 lits
- fine aggregaate =821kg/m^3
- coarse aggregate =1123kg/m^3
- chemical admixture =7.18kg/m^2
- water cement ratio = 0.4
- trial mix =1:2.28:3.12
the slump sall be measured and the water content and dosage of admixture shall be adjusted for achiving the require slump on trial.the mix propotion shall be reworked for the actual water content and checked for durability rquirements.
two more trails having variation of 0% of w/c ratio in class x shall be caried out and a graph between threee w/c ratios and corresponding strength shall be plotted to work out the mix propotions for the given taget strength for field trials however durability shall be met.
Reasults:
- Concrete Mix Design for M35 grade concrete with fly ash prapotion 1:2.08:2.72 and water cement ratio is 0.44
- Concrete Mix Design for M50 grade concrete without fly ash prapotion 1:2.28:3.12 and water cement ratio 0.4
APPENDIX
tabile : 5 (Extract of IS 456 - 2000)
according to environmental exposure condition as per tabile - 5 is 456-2000
|
TABLE.5 IS456-2000 S.NO. |
mimimum cement content plain concreate |
maximum cement ratio plain concreate | minimum grade of cement plain concreate | mimimum cement content reinforced cement concreate | maximum cement ratio reinforced cement concreate | minimumgrade of cement reinforced cement concreate | |
| 1.mild | 220 | 0.6 | - | 300 | 0.55 | m20 | |
| 2.moderate | 240 | 0.6 | m15 | 300 | 0.50 | m25 | |
| 3.seveare | 250 | 0.5 | m20 | 320 | 0.45 | m30 | |
| 4.very seveare | 260 | 0.45 | m20 | 340 | 0.45 | m35 | |
| 5.extreame | 280 | 0.40 | m25 | 360 | 0.40 | m40 |
IS 10262 -2009 is used to Table-2 maximum water content for the nominal size of aggregate
|
si.no. |
nominal maximum size of aggregate(mm) |
maximum water content(kgs) |
|
1 |
10 |
208 |
|
2 |
20 |
186 |
|
3 |
40 |
165 |
STANDERD DEVIATION:
|
Sl.No. |
Grade of Concrete |
Assumed Standard Deviation N/mm2
|
|
i) ii) |
M 10 M 15 |
3.5 |
|
iii) iv) |
M 20 M 25 |
4.0 |
|
v) vi) vii) viii) ix) x) |
M 30 M 35 M 40 M 45 M 50 M 55 |
5.0 |
TABLE-3 MAXIMUM WATER CONTENTS PER CUBIC METRE OF CONCRETE FOR NOMINAL MAXIMUM SIZE OF AGGREGATE
|
Nominal max. size of aggregate mm |
Water content per cubic meter of concrete kg |
|
10 |
208 |
|
20 |
186 |
|
40 |
165 |
TABLE NO-4 VOLUME OF COARSE AGGREGATE PER UNIT VOLUME OF TOTAL AGGREGATE FOR DIFFERENT ZONES OF FINE AGGREGATE:
|
Sl.No. |
Nominal Maximum Size of Aggregate mm |
Volume of Coarse Aggregate# per Unit Volume of Total Aggregate for Different Zones of Fine Aggregate |
|||
|
Zone IV |
Zone III |
Zone II |
Zone I |
||
|
i) |
10 |
0.50 |
0.48 |
0.46 |
0.44 |
|
ii) |
20 |
0.66 |
0.64 |
0.62 |
0.60 |
|
iii) |
40 |
0.75 |
0.73 |
0.71 |
0.69 |
Volumes are based on aggregate in saturated surface dry condition