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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 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
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.
If you have a query, you can ask a question here.
As per IS 456 the allowable mamimum cement content excluding Admixture(miniral) is 450Kg. Hence, “Is this mix does not violate the codel requirement?”
even sometimes by following fully codal requirements one can not get the strength . and yes design above then M-60 violets codal requirements.
What is the impact of using 100% crushed sand in concrete from strength & durability point of view?
if i m right at understanding your question u r asking that what if u r using the crushed fine aggregate which is known as standard aggregate .
so ok off course u will get higher strength. because crushed fine aggregates are well graded aggregates .
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
sir heat can be reduced by adding some ice cubes at site and it can be controlled by proper day night curing .
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
my frnd ravi actually the noumber 43 nd 53 representing the strength of cube of that perticular graded cement . so of course 53 is better than 43 .
opc 52.5 or 42.5. not 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
cement+fly ash+micro sillica using astp1 admixture
I want m70 design mix using only crusher sand
plz update the current detail for me through email
i want m70 grade of concrete mix ratio and design
for m70 grade our propotions are c.a-553 kg/m^3
f.a-887kg/m^3
w/c ratio-0.32
water-150lit/m^3
silica/cement ratio-0.1
superplasticizer-40ml for one 15*15 cube
so we are not getting strength sir can u tell modifications
I dont under stant how to take {total volum of ca&fa = 1.00-(0.155+0.044+0.022+0.02+0.154) =0.619
and this formula wher i use ?
plz replay me sir.7045332335
Total volume of CA and FA used = 1.00-(0.155+0.044+0.022+0.02 +0.154)
= 0.619 Cum (how to taken=0.155+0.044+0.022+0.02+0.154)
I dont understand ? 7045332335
As per IS-CODE what is the maximum and minimum cement content for M-70
Can we add admix & how much for M70 once TM reaches site in order to increase flow
We can design M-70 grade concrete with only 380 kg cement by using microfine..
I need M70 grade concrete mix ratio and weight per cubic meter (using 10mm size aggregate)
What is the right ratio mix of ingredients to attain M70
KG?
Cement:
Sand:
Aggregate: