Construction Technology_Concrete Mix Design_Project 1
1.Calculate the Concrete Mix Design for M35 grade concrete with fly ash
Aim: design of M35 concrete mix with fly ash
Properties:
STIPULATIONS FOR PROPORTIONING OF M35 GRADE CONCRETE
|
A |
Grade Designation |
M35 |
|
|
B |
Type of Cement |
OPC 53 |
|
|
C |
Type of Admixture |
Fly ash |
|
|
D |
Maximum Nominal |
20mm |
|
|
E |
Minimum Cement Content |
340kg |
Table 5-IS456 |
|
F |
Maximum Cement Content |
450kg |
As per code |
|
G |
Partial replacement |
30% |
as per requirement |
|
H |
Maximum W/C ratio |
0.45 |
Table 5-IS456 |
|
I |
Workability |
100mm |
|
|
J |
Chemical Admixture |
PCS Type |
TEST DATA FOR MATERIALS
Materials should be tested in the laboratory as per tests given in the codebook and their properties should be found. Values of the material properties will be used in the design process and to check the quality of the material with the help of codebook standards. Standard values are taken here for calculation purpose.
|
A |
Cement Used |
OPC 53 |
Confirming to |
|
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 Gravity of |
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 |
||
|
Fine aggregate |
Zone II |
Confirming to |
Procedure:
TARGET STRENGTH FOR MIX PROPORTIONS OF M35 GRADE CONCRETE
Strength of the concrete may deviate slightly depends on the quality of the material, method of mixing and construction practices. Hence target strength (Fck) should be higher than the required strength of the concrete (fck). Value of standard deviation(s) for different grade of concrete is given in Table 1 of IS456.
|
Fck |
= fck+1.65s |
“S” from Table 1-IS10262 |
|
Fck |
= 35+1.65×5 |
|
|
Fck |
= 43.25 N/mm2 |
SELECTION OF WATER-CEMENT RATIO
The maximum water-cement ratio for different grade of concrete is given in Table 5-IS456. You can reduce the water-cement ratio based on your requirements. 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 |
SELECTION OF WATER CONTENT
|
Maximum Water Content |
=186 L |
Above water-content is for 25 to 50mm slump but the slump we require is 100mm. hence we need to increase the water content to get the required slump for good workability. Clause 4.2 of IS1026 suggests an increase of 3% of water content from its original value for every increase of 25mm. Here we have a 50mm increase in the water content hence we have to increase the water content by 6 %.
|
Water-content for 100mm Slump |
=186+(0.06*186) |
|
=197.16 L |
Since super plasticizers are used water content can be reduced to get good strength of concrete. Percentage of reduction of water depends on the type of super plasticizers used in the concrete.
|
Percentage of Reduction in water content |
=20% |
|
Water content requirement after SP |
=198 – (0.20*198) |
|
=157.73 |
|
|
Adopted Water Content |
=160 L |
CALCULATION OF CEMENT AND FLY ASH CONTENT
|
Adopted Water Cement Ratio |
=0.45 |
|
Total Cementitious (Cement +Fly ash) requirement |
= Water Content / Water-Cement ratio |
|
=160/0.45 |
|
|
=355.55 kg |
Since Fly ash is used the amount of Cementitious content (Cement+Fly ash) shall be increased to get good workability and strength. the percentage of increase depending on experience and research. Here we increased the cementitious content by 1.1 %.
|
Final Cementitious |
= 356*1.1 |
|
|
=391.6 kg |
||
|
Minimum Cement Content |
=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
COARSE AND FINE AGGREGATE
|
Coarse Aggregate ratio |
= 0.62 |
(For W/C =0.5) |
|
Coarse Aggregate ratio |
= 0.63 |
(adding 0.01 for every |
|
Final Fine Aggregate ratio |
= 0.37 |
(1-0.63) = 0.37 |
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 Super plasticizers |
= Super plasticizers /(S.G*1000) |
|
= 2.35/(1.12*1000) |
||
|
= 0.002 cum |
||
|
F |
Total Aggregates requirement |
= A – (B+C+D+E) |
|
=1 -(0.087 +0.041+0.160+0.002) |
||
|
=0.71 cum |
||
|
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 Super plasticizer 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 |
RESULT:
To find the design mix ratio divide the calculated value of all materials by the weight of cement. 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
Tables used:
Table 5-IS456 and Table 1-IS10262
2.M50 grade concrete without Fly ash
Aim: To design M50 grade concrete mix
Properties:
STIPULATIONS FOR PROPORTIONING OF M50 GRADE CONCRETE
|
A |
Grade Designation |
M50 |
|
|
B |
Type of Cement |
OPC 53 |
|
|
C |
Type of Admixture |
No admixture used |
|
|
D |
Maximum Nominal |
20mm |
|
|
E |
Minimum Cement Content |
340kg |
Table 5-IS456 |
|
F |
Maximum Cement Content |
450kg |
As per code |
|
G |
Maximum W/C ratio |
0.45 |
Table 5-IS456 |
|
H |
Workability |
100mm |
|
|
I |
Chemical Admixture |
PCS Type |
TEST DATA FOR MATERIALS
Materials should be tested in the laboratory as per tests given in the codebook and their properties should be found. Values of the material properties will be used in the design process and to check the quality of the material with the help of codebook standards. Standard values are taken here for calculation purpose.
|
A |
Cement Used |
OPC 53 |
Confirming to |
|
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 Gravity of |
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 |
||
|
Fine aggregate |
Zone II |
Confirming to |
Procedure:
TARGET STRENGTH FOR MIX PROPORTIONS OF M35 GRADE CONCRETE
Strength of the concrete may deviate slightly depends on the quality of the material, method of mixing and construction practices. Hence target strength (Fck) should be higher than the required strength of the concrete (fck). Value of standard deviation(s) for different grade of concrete is given in Table 1 of IS456.
|
Fck |
= fck+1.65s |
“S” from Table 1-IS10262 |
|
Fck |
= 50+1.65×5 |
|
|
Fck |
= 58.25 N/mm2 |
SELECTION OF WATER-CEMENT RATIO
The maximum water-cement ratio for different grade of concrete is given in Table 5-IS456. You can reduce the water-cement ratio based on your requirements. 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 |
SELECTION OF WATER CONTENT
|
Maximum Water Content |
=186 L |
Above water-content is for 25 to 50mm slump but the slump we require is 100mm. hence we need to increase the water content to get the required slump for good workability. Clause 4.2 of IS1026 suggests an increase of 3% of water content from its original value for every increase of 25mm. Here we have a 50mm increase in the water content hence we have to increase the water content by 6 %.
|
Water-content for 100mm Slump |
=186+(0.06*186) |
|
=197.16 L |
Since super plasticizers are used water content can be reduced to get good strength of concrete. Percentage of reduction of water depends on the type of super plasticizers used in the concrete.
|
Percentage of Reduction in water content |
=20% |
|
Water content requirement after SP |
=198 – (0.20*198) |
|
=157.73 |
|
|
Adopted Water Content |
=160 L |
CALCULATION OF CEMENT AND FLY ASH CONTENT
|
Adopted Water Cement Ratio |
=0.45 |
|
|
Total Cement requirement |
= Water Content / Water-Cement ratio |
|
|
=160/0.45 |
||
|
=355.55 kg |
||
|
Minimum Cement Content |
=340kg |
Table 5-IS456 |
|
Adopted Cement content |
=356 kg |
> 340kg |
COARSE AND FINE AGGREGATECalculation of Super Plasticiers @ 0.6 percent to the mass of cementitious content = = 356*(0.6/100) = 2.14 kg
|
Coarse Aggregate ratio |
= 0.62 |
(For W/C =0.5) |
|
Coarse Aggregate ratio |
= 0.63 |
(adding 0.01 for every |
|
Final Fine Aggregate ratio |
= 0.37 |
(1-0.63) = 0.37 |
MIX CALCULATIONS OF M50 GRADE CONCRETE
|
A |
Volume of Concrete |
= 1 cu.m |
|
B |
Total Volume of Cement |
= Cement/(S.G*1000) |
|
= 356/(3.15*1000) |
||
|
= 0.113 cu.m |
||
|
C |
Volume of Water |
=Water /(S.G*1000) |
|
= 160/(1*1000) |
||
|
= 0.160 cu.m |
||
|
D |
Volume of Super plasticizers |
= Super plasticizers /(S.G*1000) |
|
= 2.12/(1.12*1000) |
||
|
= 0.0018 cum |
||
|
E |
Total Aggregates requirement |
= A – (B+C+D) |
|
=1 -(0.133+0.160+0.0018) |
||
|
=0.705 cum |
||
|
F |
Coarse Aggregate (C.A) |
= E * C.A ratio * S.G * 1000 |
|
= 0.705*0.63 *2.74 *1000 |
||
|
= 1216.97 kg |
||
|
G |
Fine Aggregate (F.A) |
= E * F.A ratio * S.G * 1000 |
|
= 0.705*0.37*2.74 *1000 |
||
|
=714.72kg |
Cement, Sand, Aggregate, Water and Super plasticizer needed for M50 grade concrete
|
S.No. |
MATERIALS |
QUANTITY |
|
1 |
Cement |
356 kg |
|
2 |
Fine Aggregate |
715 kg |
|
3 |
Coarse Aggregate (20mm) |
1217 kg |
|
4 |
WATER |
160 L |
|
5 |
PCE based SuperPlasticizer |
2 L |
RESULT:
To find the design mix ratio divide the calculated value of all materials by the weight of cement. Therefore Mix Ratio of M50 Grade concrete by weight is Cement: F.A: C.A = 1:0.5:0.3
Tables used:
Table 5-IS456 and Table 1-IS10262