Grade of Concrete : M35
Characteristic Strength (Fck) : 35 Mpa
Standard Deviation : 1.91 Mpa*
Target Mean Strength : T.M.S.= Fck +1.65 x S.D.(from I.S 456-2000)
= 35+ 1.65×1.91
= 38.15 Mpa
Test Data For Material:
Aggregate Type : Crushed
Specific Gravity
Cement : 3.15
Coarse Aggregate : 2.67
Fine Aggregate : 2.62
Water Absorption:
Coarse Aggregate : 0.5%
Fine Aggregate : 1.0 %
MIX DESIGN:
Take Sand content as percentage of total aggregates = 36%
Select Water Cement Ratio = 0.43 for concrete grade M35
(From Fig 2. of I.S. 10262- 1982)
Select Water Content = 172 Kg
(From IS: 10262 for 20 mm nominal size of aggregates Maximum Water Content = 186 Kg/ M3 )
Hence, Cement Content= 172 / 0.43 = 400 Kg / M3
Formula for Mix Proportion of Fine and Coarse Aggregate:
1000(1-a0) = {(Cement Content / Sp. Gr. Of Cement) + Water Content +(Fa / Sp. Gr.* Pf )}
1000(1-a0) = {(Cement Content / Sp. Gr. Of Cement) + Water Content +Ca / Sp. Gr.* Pc )}
Where
Ca = Coarse Aggregate Content
Fa = Fine Aggregate Content
Pf = Sand Content as percentage of total Aggregates = 0.36
Pc = Coarse Aggregate Content as percentage of total Aggregates.= 0.64
a0 = Percentage air content in concrete (As per IS :10262 for 20 mm nominal size of aggregates air content is 2 %) = 0.02
Hence, 1000(1-0.02) = {(400 /3.15) + 172 +(Fa / 2.62 x 0.36)}
Fa = 642 Kg/ Cum
As the sand is of Zone II no adjustment is required for sand.
Sand Content = 642 Kg/ Cum
1000(1-0.02) = {(400 /3.15) + 172 +(Ca / 2.67 x 0.64)}
Hence, Ca = 1165 Kg/ Cum
From combined gradation of Coarse aggregates it has been found out that the proportion of 53:47 of 20 mm & 10 mm aggregates produces the best gradation as per IS: 383.
Hence, 20 mm Aggregates = 619 Kg
And 10 mm Aggregates = 546 Kg
To obtain slump in the range of 150-190 mm water reducing admixture brand SP430 from Fosroc with a dose of 0.3 % by weight of Cement shall be used.
Hence the Mix Proportion becomes:
Cement | W/C | Water | Sand | 20mm(agg.) | 10mm(agg.) | Admix |
400 | 0.43 | 172 | 635 | 619 | 564 | 1.2 |
1 | 0.43 | 1.6 | 1.547 | 1.36 | 0.003 |
Units – Kg/ M3
Cement : Sand: Coarse Aggregates = 1 : 1.6 : 2.907
OR
CONCRETE MIX DESIGN |
||
As per IS 10262-2009 & MORT&H |
||
A-1 |
Stipulations for Proportioning | |
1 |
Grade Designation | M35 |
2 |
Type of Cement | OPC 53 grade confirming to IS-12269-1987 |
3 |
Maximum Nominal Aggregate Size | 20 mm |
4 |
Minimum Cement Content (MORT&H 1700-3 A) | 310 kg/m^{3} |
5 |
Maximum Water Cement Ratio (MORT&H 1700-3 A) | 0.45 |
6 |
Workability (MORT&H 1700-4) | 50-75 mm (Slump) |
7 |
Exposure Condition | Normal |
8 |
Degree of Supervision | Good |
9 |
Type of Aggregate | Crushed Angular Aggregate |
10 |
Maximum Cement Content (MORT&H Cl. 1703.2) | 540 kg/m^{3} |
11 |
Chemical Admixture Type | Superplasticiser Confirming to IS-9103 |
A-2 |
Test Data for Materials | |
1 |
Cement Used | Coromandal King OPC 53 grade |
2 |
Sp. Gravity of Cement | 3.15 |
3 |
Sp. Gravity of Water | 1.00 |
4 |
Chemical Admixture | BASF Chemicals Company |
5 |
Sp. Gravity of 20 mm Aggregate | 2.884 |
6 |
Sp. Gravity of 10 mm Aggregate | 2.878 |
7 |
Sp. Gravity of Sand | 2.605 |
8 |
Water Absorption of 20 mm Aggregate | 0.97% |
9 |
Water Absorption of 10 mm Aggregate | 0.83% |
10 |
Water Absorption of Sand | 1.23% |
11 |
Free (Surface) Moisture of 20 mm Aggregate | nil |
12 |
Free (Surface) Moisture of 10 mm Aggregate | nil |
13 |
Free (Surface) Moisture of Sand | nil |
14 |
Sieve Analysis of Individual Coarse Aggregates | Separate Analysis Done |
15 |
Sieve Analysis of Combined Coarse Aggregates | Separate Analysis Done |
15 |
Sp.Gravity of Combined Coarse Aggregates | 2.882 |
16 |
Sieve Analysis of Fine Aggregates | Separate Analysis Done |
A-3 |
Target Strength for Mix Proportioning | |
1 |
Target Mean Strength (MORT&H 1700-5) | 47N/mm^{2} |
2 |
Characteristic Strength @ 28 days | 35N/mm^{2} |
A-4 |
Selection of Water Cement Ratio | |
1 |
Maximum Water Cement Ratio (MORT&H 1700-3 A) | 0.45 |
2 |
Adopted Water Cement Ratio | 0.4 |
A-5 |
Selection of Water Content | |
1 |
Maximum Water content (10262-table-2) | 186 Lit. |
2 |
Estimated Water content for 50-75 mm Slump | 160 Lit. |
3 |
Superplasticiser used | 0.5 % by wt. of cement |
A-6 |
Calculation of Cement Content | |
1 |
Water Cement Ratio | 0.4 |
2 |
Cement Content (160/0.42) | 400 kg/m^{3} |
Which is greater then 310 kg/m^{3} | ||
A-7 |
Proportion of Volume of Coarse Aggregate & Fine Aggregate Content | |
1 |
Vol. of C.A. as per table 3 of IS 10262 | 62.00% |
2 |
Adopted Vol. of Coarse Aggregate | 62.00% |
Adopted Vol. of Fine Aggregate ( 1-0.62) | 38.00% | |
A-8 |
Mix Calculations | |
1 |
Volume of Concrete in m^{3} | 1.00 |
2 |
Volume of Cement in m^{3} | 0.13 |
(Mass of Cement) / (Sp. Gravity of Cement)x1000 | ||
3 |
Volume of Water in m^{3} | 0.160 |
(Mass of Water) / (Sp. Gravity of Water)x1000 | ||
4 |
Volume of Admixture @ 0.5% in m^{3} | 0.00168 |
(Mass of Admixture)/(Sp. Gravity of Admixture)x1000 | ||
5 |
Volume of All in Aggregate in m^{3} | 0.711 |
Sr. no. 1 – (Sr. no. 2+3+4) | ||
6 |
Volume of Coarse Aggregate in m^{3} | 0.441 |
Sr. no. 5 x 0.62 | ||
7 |
Volume of Fine Aggregate in m^{3} | 0.270 |
Sr. no. 5 x 0.38 | ||
A-9 |
Mix Proportions for One Cum of Concrete (SSD Condition) | |
1 |
Mass of Cement in kg/m^{3} | 400 |
2 |
Mass of Water in kg/m^{3} | 160 |
3 |
Mass of Fine Aggregate in kg/m^{3} | 704 |
4 |
Mass of Coarse Aggregate in kg/m^{3} | 1271 |
Mass of 20 mm in kg/m^{3} | 915 | |
Mass of 10 mm in kg/m^{3} | 356 | |
5 |
Mass of Admixture in kg/m^{3} | 2.00 |
6 |
Water Cement Ratio | 0.40 |