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

Posted in Mix Design | Email This Post |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/mm^{2}

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/mm^{2} @ 3 days

51.0 N/mm^{2} @ 7 days

64.2 N/mm^{2} @ 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/mm^{2}

Target mean strength : Depend upon degree of quality control “good” and considering (std. Dev.As 5 N/mm^{2})

Characteristic strength given by the relation 70 +(1.65 *5 ) = 78.25 N/mm^{2}

**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/mm ^{2})**

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.*

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

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

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

I cant understand your calculations for heat of hydration…. can you please elaborate..

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.

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

compulsary add admixture for m70 grade

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

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

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