The mix design for M35 Grade Of Concrete for pile foundations provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.
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:
Cem
W/C
Water
Sand
20mm
10mm
Admix
cem 400 - 1
w/c 0.43
water 172 - 0.43
sans 635 - 1.6
20mm Agg. 619 - 1.547
10mm Agg. 564 - 1.36
Add mix 1.2 - 0.003
Units – Kg/ M3
Cement : Sand: Coarse Aggregates = 1 : 1.6 : 2.907