M35 Grade Of Concrete – Concrete Mix Design

concrete-mix-design

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

Water Absorption:
Coarse Aggregate : 0.5%
Fine Aggregate : 1.0 %

Specific Gravity
Cement : 3.15
Coarse Aggregate : 2.67
Fine Aggregate : 2.62

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
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

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