Project on Concrete Mix Design for various grades of Concrete
M35 grade concrete with fly ash
STEP1: stipulation for concret design mix
Grade designation :M35
Type of cement :OPC 43 grade confirming to IS 8112
Type of mineral admixture:fly ash confirming to IS 3812(part1)
Maximum nominal size :20mm
of aggregates
Minimum cement content :320 kg/m^3(from table 5 of IS 456,exposure condition )
Maximum water cement ratio:0.45
workability :100mm slump
Exposure condition : severe
Method of concrete placing:pumping
Degree of supervision :good
Type of aggregate :crushed angular
Maximum cement content : 450kg/m^3
Chemical admixture type :super plasticizer
STEP 2: TEST DATA FOR MINERALS
Cement used :OPC 43 grade confirming IS8112
Specific gravity of cement :3.15
fly ash :part1 of IS 3812
Specific gravity of fly ash :2.2
Chemical admixture : suoer platicizer
Specific gravity of coarse :2.74
aggregate
Specific gravity of :2.74
fine aggregate
Water abosrption of :0.5%
coarse aggregate
Water absorption of :1%
fine aggregate
STEP 3: TARGET STRENGTH FOR MIX PROPORTION
Fm=fck+1.65s
=35+1.65*5=43.25N/mm^2
Target mean strength =43.25n/mm^2
STEP 4: SELECTION OF WATER CEMENT RATIO
w/c=0.45
based on experience =0.44<0.45 ok
ADOPTED W/C =0.44
STEP:5 SELECTION OF WATER CONTENT
From IS10262:2009 ,table 2
water content=186+(6/100)*186=197 litre
based on admixture used
water content =197*0.8=158litre
water required =158 litres
Calculation of cement and fly ash
adopted W/C=0,44
cement+fly ash required=158/0.44=359kg/m^3
final cementious content=359*1.10=395kg >320 kg(minimum as per IS 456)
new water content ratio =158/395=0.4
fly ash as 30% of total cementious material=395*0.3=118.5kg/m^3
cement required 395-118=277kg/m^3
cementious material,cement and fly ash required is 395kg/m^3,277kg/m^3 and 118kg/m^3 and w/c ratio=0.4 respectively
STEP:7 VOLUME OF COARSE AND FINE AGGREGATE CONTENT
from IS10262:2009 (table 3)
vol. of coarse aggregate=0.632*0.9=0.568
vol. 0f fine aggregate =1-0.568=0.431
STEP:8 MIX CALCULATIONS
mix calculation per unit volume of concrte are as follow
a) vol. of concrete=1m^3
b) vol. of cement=(277/3.15)*(1/1000)=0.087m^3
c) vol. of fly ash=(118/2.2)*(1/1000)=0.053
d) vol. of water=(158/1)*(1/1000)=0.158m^3
e) vol.of admixture=(7.6/1.145)*(1/1000)=0.006m^3
f) vol. of all in aggregate=[a-(b+C+D+E)]=0.696m^3
g) mass of coarse aggregate= 0.696*0.568*2.74*1000=1077kg/m^3
h) mas s of fine aggregate=0.696*0.431*2.74*1000=822kg/m^3
STEP:9 mix proportioning
Cement=277kg/m^3
Fly ash=118 kg/m^3
Water=158l/m^3
fine aggregate=822kg/m^3
coarse aggregate of 20mm =1077kg/m^3
chemical admixture=7.18kg/m^3
W/C ratio(lowest selected)=0.4
MIX proportion by weight=1:2.08:2.72
STEP:10
The slump shall be measured, the water content and dosage of admixture shall be adjusted for achieving the required slump on trail. The mix proportion shall be reworked for the actual water content and check the durability requirement.
STEP:11 Two more trails having variation of 10% of W/C ratio shall be carried out.
CALCULATION OF M50 GRADE CONCRTE MIX DESIGN WITHOUT FLY ASH
STEP:1 stipulations for concrete design miX
Grade designation : M50
Type of cement OPC 53 grade
Max. nominal six=ze of coarse aggregate :20mm
Minimum cement content :320kg/m^3
W/C ratio 0.45 Workability :100mm slump
Exposure condition :severe
Method of concrete placing :pumping
Degree of supervision :good
Type of aggregate :angular crushed
Maxmimum cement content :450kg/m^3
Chemical admixture :super platicizer
STEP:2 TEST DATA FOR MINERALS
Cement used : OPC 53 grade
specific gravity of cement : 3.15
chemical admixture : super platicizer
specific gravity of coarse aggregate :2.74
specific gravity of fine aggregate :2.64
STEP:3 TARGET STRENGTH FOR MIX PROPORTIONING
Fm=fck+1.65s=50+1.65*5=58.25N/mm^2
Target mean strength =58.25N/mm^2
STEP:4 SELECTION OF WATER-CEMENT RATIO
from IS 456:2000 table 5
W/C ratio =0.45
Adopted W/C ratio=0.44(based on experienced)
STEP:5 SELECTION OF WATER CONTENT
from IS10262:2009, table 2
water content= 186+(6/100)*186=197litre
when platicizer is used , it reduced upto 20%
water content= 197*0.8=158 litre
water required =158 litres
STEP:6 calculation of cement required
cement content=158/0.44=359kg/m^3
STEP:7 volume of aggregates
from IS10262,table3
vol. of coarse aggregates=0.632*0.9=0.568
vol. of fine aggregates=1-0.576=0.431
STEP:8 MIX CALCULATION
a)vol. opf concrete=1m^3
b)vol. of cement=(359/3.15)*(1/1000)=0.114m^3
c)vol. of water=(158/1)*(1/1000)=0.158m^3
d)vol. of chemical admixture=(7.6/1.145)*(1/1000)=0.006m^3
e)vol. of all in aggregate=a-(b+C+D)=0.722m^3
f)mass of coarse aggregates= 0.722*0.568*2.74*1000=1123kg/m^3
g)mass of fine aggregates=0.722*0.431*2.64*1000=821kg/m^3
STEP :9 MIX PROPORTION
cement 359kg/m^3
water 158l/m^3
fine aggregate 821kg/m^3
coarse aggregate 1123 of 20 mm kg/m^3
w/c ratio 0.44
mix proportion by weight 1:2.28:3.12
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