AIM: TO CALCULATE THE CONCRETE MIXDESIGN FOR M35 GRADE OF CONCRETE WITH FLYASH.
INTRODUCTION:CONCRETE MIX DESIGN IS THE METHOD OF FINDING the precise proportion of cement sand and aggregates for concrete to achive the target strength in structures therefore concrete mix design can be stated as concrete mix in terms cement: sand: aggregates. the design is done according to the requriments concrete strength. so we can achive the desired state of concrete either in fresh stage or harden stage.
objective: the objective of this project is to produce a mix design for m 35 grade of concrete containing flyash.
the mix will be prepared as per IS method concrete mix proportioning guidelines from IS 10262: 2009 and recomended guidelines from IS 10262:1982. AND ALSO DIFFRENT TABLES CODES AS PER RULES.
PROCEDURE:
A
Grade Designation
M35
B
Type of Cement
OPC 53
C
Type of Admixture
Fly ash
D
Maximum Nominal Size of Aggregate
20mm
E
Minimum Cement Content
340kg
table 5 IS -456
F
Maximum Cement Content
450kg
As per code
G
Partial replacement of cement by Fly ash
30%
as per requirement
H
Maximum W/C ratio
0.45
table 5 IS -456
I
Workability
100mm
J
Chemical Admixture
PCS Type
II. TEST DATA FOR MATERIALS
Materials must be tested to find its below physicals and chemical properties. Standard values are considered below.
A
Cement Used
OPC 53
Confirming to IS8112
B
Specific Gravity of Cement
3.15
Test – IS: 2720
C
Mineral Admixture
Fly ash
Confirming to IS12089
D
Specific Gravity of Fly ash
2.90
E
Chemical Admixture
@0.6%
IS9103
F
Specific Gravityof
Test – IS 2386
Coarse Aggregate
2.74
Fine Aggregate
2.74
Admixture PCE based
1.12
G
Water Absorption
Test – IS 2386
Coarse aggregate
0.5 %
Fine aggregate
1 %
H
Sieve Analysis
Test – IS 2386
Coarse aggregate
Confirming to Table 2-IS383
Fine aggregate
Zone II
Confirming to Table 4-IS383
III. TARGET STRENGTH FOR MIX PROPORTIONS OF M35 GRADE CONCRETE
The strength of concrete may vary depending on the quality of the material, the mixing method and the construction procedures. Therefore the target strength (Fck) must be greater than the required strength of the concrete (fck).
Table 1 of IS456 gives the standard deviation value (s) for different grade concretes.
Fck
= fck+1.65s
“S” from table IS 10262.
Fck
= 35+1.65×5
Fck
= 43.25 N/mm2
IV. SELECTION OF WATER-CEMENT RATIO
The maximum water-cement ratios for different grades of concrete are given in Table 5-IS456. You can reduce the water-cement ratio based on your needs.
The water-cement ratio directly affects the strength of the concrete.
Maximum W/C ratio
=0.45
TABLE 5 IS456
Adopted W/C ratio
=0.45
V. SELECTION OF WATER CONTENT
Maximum Water Content
=186 L
TABLE 2-IS 1026
The water content above is for a sluMP of 25 to 50 mm, but according to the specification our concrete requires a slump of 100 mm. Therefore, to get the desired slump, the water content must be increased. Clause 4.2 of IS1026 recommends increasing the water content by 3% to obtain an additional 25 mm slump. Therefore, to obtain a slump of 50 mm in addition to our concrete, the water content must be increased by 6%.
Water-content for 100mm Slump
=186+(0.06*186)
=197.16 L
As we use super plasticizers we can reduce the water content to gain strength in the concrete. The amount of water-content to be reduced depends on the type of super plasticizer.
Percentage of Reduction in water content
=20%
Water content requirement after SP
=198 – (0.20*198)
=157.73
Adopted Water Content
=160 L
VI. CALCULATION OF CEMENT AND FLY ASH CONTENT
Adopted Water Cement Ratio
=0.45
Total Cementitious (Cement +Fly ash) requirement
= Water Content / WaterCement ratio
=160/0.45
=355.55 kg
Since flying ash is used, the amount of cementitious content (cement + fly ash) should be increased to get good performance and strength. The percentage of increasing cementitious content depends on experience and research. Here we have increased the cementitious content by 10%.
Final Cementitious Content (Cement+Fly ash)
= 356*1.10
=391.6 kg
Minimum Cement Content required for ‘severe’ exposure
=340kg
Table 5-IS456
Adopted Cementious content
=391.6 kg
> 340kg
Fly ash content requirement
= 391.6 * 0.30
30% replacement
= 117.48 ~ 118 kg
Cement Content requirement
=Cementious content – Fly ash
=391.6-117.48
= 274.12
Calculation of Super Plasticiers @ 0.6 percent to the mass of cementitious content = = 391.6*(0.6/100) = 2.35 kg
VII COARSE AND FINE AGGREGATE
Coarse Aggregate ratio
= 0.62
TABLE 3 IS -10262 (For W/C =0.5)
Coarse Aggregate ratio for 0.45 w/c ratio
= 0.63
(adding 0.01 for every decrease .05 and vice versa)
Final Fine Aggregate ratio
= 0.37
(1-0.63) = 0.37
VIII MIX CALCULATIONS OF M35 GRADE CONCRETE
A
Volume of Concrete
= 1 cu.m
B
Total Volume of Cement
= Cement/(S.G*1000)
= 275/(3.15*1000)
= 0.087 cu.m
C
Total Volume of Fly ash
= Flyash/(S.G*1000)
= 118/(2.5*1000)
= 0.041 cu.m
D
Volume of Water
=Water /(S.G*1000)
= 160/(1*1000)
= 0.160 cu.m
E
Volume of Superplasticizers
= Superplasticizers /(S.G*1000)
= 2.35/(1.12*1000)
= 0.002 cu.m
F
Total Aggregates requirement
= A – (B+C+D+E)
=1 -(0.087 +0.041+0.160+0.002)
=0.71 cu.m
G
Coarse Aggregate (C.A)
= F * C.A ratio * S.G * 1000
= 0.71*0.63 *2.74 *1000
= 1225.6 kg
I
Fine Aggregate (F.A)
= F * F.A ratio * S.G * 1000
= 0.71*0.37*2.74 *1000
=719.8 kg
Cement Flyash Sand Aggregate Water and Superplasticizer needed for M35 grade concrete
S.No.
MATERIALS
QUANTITY
1
Cement
275 kg
2
Flyash
118 kg
3
Fine Aggregate
720 kg
4
Coarse Aggregate (20mm)
1226 kg
5
WATER
160 L
6
PCE based SuperPlasticizer
2 L
FINAL RESULT=Therefore Mix Ratio of M35 Grade concrete by weight is
Cement : Flyash: F.A : C.A : Water = 1:0.4:2.6:4.46:0.58
the Concrete Mix Design for M50 grade concrete without Fly ash.
AIM :TO Calculate the Concrete Mix Design for M50 grade concrete without Fly ash
INTRODUCTION:CONCRETE MIX DESIGN IS THE METHOD OF FINDING the precise proportion of cement sand and aggregates for concrete to achive the target strength in structures therefore concrete mix design can be stated as concrete mix in terms cement: sand: aggregates. the design is done according to the requriments concrete strength. so we can achive the desired state of concrete either in fresh stage or harden stage.
objective: the objective of this project is to produce a mix design for m 50 grade of concrete WITHOUT USING flyash.
the mix will be prepared as per IS method concrete mix proportioning guidelines from IS 10262: 2009 and recomended guidelines from IS 10262:1982.
PROCEDURE
Grade designation : M 50
Type of cement : OPC 53 grade confirming to IS 8112
From Table 2 of IS 456 maximum water content =186 litres (for 25 to 50 mm slump range) for 20 mm aggregate.
Estimated water content for 100 mm slump =186+(6/100) x 186 =197 litres.
(Note: If Super plasticizer is used, the water content can be reduced up to 20% and above.)
Based on trials with Super plasticizer water content reduction of 27% has been achieved, Hence the arrived water content = 197 – [197 x (27/100)] = 143 litres.
4. Calculation of Cement Content
Water-cement ratio = 0.35
Cement content = 143/0.35 = 410 kg/m3
From Table 5 of IS 456, minimum cement content for ‘Extreme exposure’ condition = 360 kg/m3
410 kg/m3 > 360 kg/m3, hence, O.K.
5. Proportion of Volume of Coarse Aggregate and Fine Aggregate Content
From Table 3 of IS10262 volume of coarse aggregate corresponding to 20 mm size aggregate and fine aggregate (Zone II) for a water-cement ratio of 0.50 =0.62.
In the present case, the water-cement ratio is 0.35. Therefore. the volume of coarse aggregate is required to be increased to decrease the fine aggregate content. As the water-cement ratio is lower by 0.10. the proportion of the volume of coarse aggregate is increased by 0.02 (at the rate of -/+ 0.01 for every ± 0.05 change in the water-cement ratio).
Therefore. the corrected proportion of the volume of coarse aggregate for the water-cement ratio of 0.35 = 0.65.
NOTE – In case the coarse aggregate is not angular one, then the volume of coarse aggregate may be increased by 10 percent based on experience.
For pumpable concrete, these values should be reduced by 10 percent.
Therefore, volume of coarse aggregate = 0.65 x 0.9 = 0.585.
Volume of fine aggregate content =1 – 0.585 =0.415
6. Mix Calculations
a) Volume of concrete = 1m3
b) Volume of cement = (Mass of Cement/ Its Specific Gravity ) X (1/1000)
= (410/3.12) X (1/1000)
= 0.131 m3
c) Volume of Water = (Mass of water/specific gravity of water) X (1/1000)
= (143/1) X (1/1000)
= 0.143 m3
d) Volume of Superplasticizer = (Mass of Superplasticizer / Specific gravity of admixture) X (1/1000)
= (8.2/1.145) X (1/1000)
= 0.007 m3
e) Volume of all aggregate = (a – (b + c + d))
= 1 – (0.131 + 0.143+0.007)
= 0.719 m3
e) Mass of coarse aggregate = Volume of All Aggregate X Volume of Coarse Aggregate X Specific Gravity of Coarse Aggregate X 1000
= 0.719 x 0.585 x 2.74 x 1000
= 1152.48 kg
f) Mass of fine aggregate = Volume of all aggregate X volume of fine aggregate X Specific gravity of fine aggregate X 1000
= 0.719 x 0.415 x 2.56 x 1000
= 763.86 kg
7. Concrete Mix Proportions
Cement = 410 kg/m3
Water = 143 kg/m3
Super plasticizer = 7 kg/m3
Fine aggregates = 763.86 kg/m3
Coarse aggregate = 1152.48 kg/m3
W/c = 0.35
FINAL RESULT=Therefore Mix Ratio of M50 Grade concrete by weight is