Mix Design M-40 Grade

The mix design M-40 grade for Pier (Using Admixture – Fosroc) provided here is for reference purposes only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.

Parameters for mix design M-40 Grade

Grade Designation = M-40
Type of cement: O.P.C.-43 grade
Brand of cement = Vikram ( Grasim )
Admixture = Fosroc ( Conplast SP 430 G8M )
Fine Aggregate = Zone-II
Sp. Gravity Cement = 3.15
Fine Aggregate = 2.61
Coarse Aggregate (20mm) = 2.65
Coarse Aggregate (10mm) = 2.66
Minimum Cement (As per contract) = 400 kg / m3
Maximum water cement ratio (As per contract) = 0.45

Mix Calculation: – Mix Design M-40 Grade

1. Target Mean Strength = 40 + (5 X 1.65) = 48.25 Mpa

2. Selection of water cement ratio:-
Assume water cement ratio = 0.4

3. Calculation of cement content: –
Assume cement content 400 kg / m3
(As per contract, Minimum cement content is 400 kg / m3)

4. Calculation of water: –
400 X 0.4 = 160 kg Which is less than 186 kg (As per Table No. 4, IS: 10262)
Hence o.k.

5. Calculation for C.A. & F.A.: – As per IS : 10262 , Cl. No. 3.5.1

V = [ W + (C/Sc) + (1/p) . (fa/Sfa) ] x (1/1000)

V = [ W + (C/Sc) + {1/(1-p)} . (ca/Sca) ] x (1/1000)

Where

V = absolute volume of fresh concrete, which is equal to gross volume (m3) minus the volume of entrapped air ,

W = mass of water ( kg ) per m3 of concrete ,

C = mass of cement ( kg ) per m3 of concrete ,

Sc = specific gravity of cement,

(p) = Ratio of fine aggregate to total aggregate by absolute volume ,

(fa) , (ca) = total mass of fine aggregate and coarse aggregate (kg) per m3 of
Concrete respectively, and

Sfa , Sca = specific gravities of saturated surface dry fine aggregate and Coarse aggregate, respectively.

As per Table No. 3 , IS-10262, for 20 mm, the maximum size of entrapped air is 2% .

Assume F.A. by % of volume of total aggregate = 36.5 %

0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.365 ) ( Fa / 2.61 )] ( 1 /1000 )

=> Fa = 660.2 kg

Say Fa = 660 kg.

0.98 = [ 160 + ( 400 / 3.15 ) + ( 1 / 0.635 ) ( Ca / 2.655 )] ( 1 /1000 )

=> Ca = 1168.37 kg.

Say Ca = 1168 kg.

Considering 20 mm : 10mm = 0.6 : 0.4

20mm = 701 kg .
10mm = 467 kg .

Hence, Mix details per m3

Cement = 400 kg
Water = 160 kg
Fine aggregate = 660 kg
Coarse aggregate: 20 mm = 701 kg
Coarse aggregate (10 mm = 467 kg
Admixture = 0.6 % by weight of cement = 2.4 kg.
Recron 3S = 900 gm

Water: cement: F.A.: C.A. = 0.4: 1: 1.65: 2.92

Observation: –
A. Mix was cohesive and homogeneous.
B. Slump = 110mm
C. No. of cube casted = 12 Nos.
7 days average compressive strength = 51.26 MPa.
28 days average compressive strength = 62.96 MPa which is greater than 48.25MPa

Hence the mix is accepted .Mix Design M-40 Grade

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