Concrete Mix Design – M70 Grade of Concrete (OPC 53 Grade)

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Concrete mix design – M70 grade of concrete provided here is for reference purpose only. Actual site conditions vary and thus this should be adjusted as per the location and other factors.

A. Design Stipulation:
Characteristic comprehensive Strength @ 28 days = 70 N/mm2
Maximum size of aggregate = 20 mm
Degree of workability = Collapsible
Degree of quality control = Good
Type of exposure = Severe
Minimum cement content as per is 456-2000

B. Test data for concrete ingredients
Specific gravity of cement = 3.15
Specific gravity of fly ash = 2.24
Specific gravity of microsilica = 2.21
Setting time of cement initial = 165 min, final = 270min
Cement compressive strength =
39.0 N/mm2 @ 3 days
51.0 N/mm2 @ 7 days
64.2 N/mm2 @ 28 days
Specific gravity of coarse aggregates (ca) and fine aggregates (fa)
20 mm 2.729
10 mm 2.747
R/sand 2.751
C/sand 2.697

Water absorption
20 mm 1.540, 10mm 1.780, R/sand 3.780, C/sand 4.490

Characteristic strength @ 28 days 70 N/mm2
Target mean strength : Depend upon degree of quality control “good” and considering (std. Dev.As 5 N/mm2)

Characteristic strength given by the relation 70 +(1.65 *5 ) = 78.25 N/mm2

C. Quantities of ingredients (By Absolute Volume Method )
Actual cement used = 486 kg/cum
Actual fly ash used = 90 kg/cum
Actual microsilica used = 24 kg/cum
W/C fixed = 0.26
Absolute volume of cement = 0.154
Absolute volume of air = 0.02
Absolute vol of water. = 0.156
Absolute vol of fly ash. = 0.040
Absolute vol of microsilica = 0.011

Total volume of CA and FA used = 1.00-(0.155+0.044+0.022+0.02 +0.154)
= 0.619 Cum

D. Aggregate percent used.
20 Mm = 24, 10 mm = 36, r/sand = 20, c/sand = 20

(2.729*0.24) + (2.747*0.36) +(2.751* 0.20 )+(2.697*0.20) *0.619*1000
405+612+340+334=1691

Aggt: cement = 2.82 : 1

Mix proportion = 0.26:1:0.57:0.56:1.02:0.67

E. Abstract:
20 mm = 405 kg/cum
10 mm = 612 kg/cum
r/sand = 340 kg /cum
c/sand = 334 kg/cum
water = 154 kg/cum

Admixture 0.50 % BY WT OF (C+F+MS) ASTP-1 OF BASF

Cube Compressive Strength (N/mm2)
3 days = 49.13
7 Days = 59.57
28 Days = 81.49

Note: Mix design is same for Crane bucket and Pump concrete only admixture dosage will fine tuned by 0.05 to 0.10%
We are thankful to Deshmukh D S for submitting this very useful mix design information to us.

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Comments
  • Min December 4, 2010 at 6:55 am

    As per IS 456 the allowable mamimum cement content excluding Admixture(miniral) is 450Kg. Hence, “Is this mix does not violate the codel requirement?”

  • Jitendra Sidhpura December 21, 2010 at 6:19 am

    What is the impact of using 100% crushed sand in concrete from strength & durability point of view?

  • mohamed hussein May 14, 2011 at 5:10 pm

    fly ash concrete OPC Concrete
    Material Quantity Heat of hydration Quantity Heat of hydration
    (kg/m3) (kJ/kg) (kJ/m3) (kg/m3) (kJ/kg) (kJ/m3)
    OPC + MS 510 314 160140 600 314 188400
    fly ash 90 122 10980 Total 188400
    600 Total 171120 kJ/m3 Thermal capacity 2631.14 kJ/m3
    Thermal capacity 2631.14 kJ/C/m3 Raise in temperature 71.6 C
    Raise in temperature 65.0 C
    Difference 6.6 C
    This mix have too much cementaiutie material, and heat of hydration theoretical calculation showing a high risk for thermal cracks ,which I not recommended any ready mix QC System to use this mix,
    mohamed hussein ahmed
    Head of SPCS ,Holcim

  • Arun Kurali June 20, 2011 at 5:57 am

    Dear jitendra:strength might be in the right path but durability goes down which will comes around 2000cu charge transfer.since the demand of water is high it may leads to fail in gaining slump under poor controls.

  • ravi prakash October 12, 2011 at 5:31 am

    tell me about which cement is better for high strength concrete.(opc 43 or opc 53) or ppc

  • rajesh November 19, 2011 at 1:17 am

    compulsary add admixture for m70 grade

  • Ashish December 30, 2011 at 9:17 am

    Sir plz help me agar hum m 70 ka slup cone main test karte hain toh slup kitna hona cahiye help me sir

  • awaneesh June 22, 2012 at 7:07 am

    what is R/sand in M-70 grade of COncrete

  • Sushil May 31, 2013 at 2:16 am

    I don’t understand the term “(C+F+MS) ASTP-1 OF BASF” Please clarify me

  • Post a comment

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