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wanboksutnga SEFI Member
Joined: 17 Mar 2013 Posts: 8
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Posted: Wed Mar 20, 2013 10:50 am Post subject: Conversion of Weight of concrete to Volume |
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Dear Sefians
Kindly check the following calculation if it is correct or not because as per mix design the proportion is by weight but i want to do it by volume.Please help which one of the two calculation is correct.Mob-8974165540
As per mix design for M30
proportion=1:1.16:3.15
For cement=50 kg Sp G=3.15
Fa =58.05 kg Sp G=2.64
Ca =157.72 kg Sp G=2.68
In volume
For cement=50 kg =50/3.15/1000=0.0158 cum
Fa =58.05 kg =58.05/2.64/1000=0.0219 cum
Ca =157.72 kg =157.72/2.68/1000=0.0588 cum
Proportion by Volume=0.0158: 0.0219: 0.0588
=1:1.38:3.72
Box gauge to be used=250x250x250=0.0156 cum
Alternatively
50 kg of cement=50/1440=0.0347 cum==0.035 cum
Fa =58.05 kg =58.05/2.64/1000=0.0219 cum
Ca =157.72 kg =157.72/2.68/1000=0.0588 cum
Proportion by Volume=0.035: 0.0219: 0.0588
=1:0.63:1.68
Box gauge to be used=300x300x380=0.0347 cum |
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Dr. N. Subramanian General Sponsor
Joined: 21 Feb 2008 Posts: 5538 Location: Gaithersburg, MD, U.S.A.
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Posted: Wed Mar 20, 2013 1:28 pm Post subject: Re: Conversion of Weight of concrete to Volume |
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Dear Er Wanbok,
The first calculation, shown in Red is correct!
Best wishes,
NS
wanboksutnga wrote: | Dear Sefians
Kindly check the following calculation if it is correct or not because as per mix design the proportion is by weight but i want to do it by volume.Please help which one of the two calculation is correct.Mob-8974165540
As per mix design for M30
proportion=1:1.16:3.15
For cement=50 kg Sp G=3.15
Fa =58.05 kg Sp G=2.64
Ca =157.72 kg Sp G=2.68
In volume
For cement=50 kg =50/3.15/1000=0.0158 cum
Fa =58.05 kg =58.05/2.64/1000=0.0219 cum
Ca =157.72 kg =157.72/2.68/1000=0.0588 cum
Proportion by Volume=0.0158: 0.0219: 0.0588
=1:1.38:3.72
Box gauge to be used=250x250x250=0.0156 cum
Alternatively
50 kg of cement=50/1440=0.0347 cum==0.035 cum
Fa =58.05 kg =58.05/2.64/1000=0.0219 cum
Ca =157.72 kg =157.72/2.68/1000=0.0588 cum
Proportion by Volume=0.035: 0.0219: 0.0588
=1:0.63:1.68
Box gauge to be used=300x300x380=0.0347 cum |
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es_jayakumar General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Wed Mar 20, 2013 2:49 pm Post subject: |
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Dear Er Wanbok,
I think, while converting the weights to equivalent volumes, you have to divide with bulk density, rather than specific gravity, so as to account for the voids in the aggregates. In your statement, the volume of one bag of cement is 0.035 cum (second calculation), which is the established value. As per the CPWD specifications, the batching box has to be of the size 25cmx35cmx40cm (0.035 cum volume) that exactly contains one bag of cement. As told by me in reply to another posting of you in a different heading, but on the same topic, correction for water content, bulking (for volume batching) etc. has to be applied if the aggregates are kept open to damp weather. Corresponding reduction should be applied to the quantity of added water as well.
Regards,
E S Jayakumar |
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B.V.Harsoda General Sponsor
Joined: 19 Jan 2009 Posts: 2329 Location: RAJKOT,GUJARAT, INDIA
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Posted: Wed Mar 20, 2013 4:17 pm Post subject: |
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Dear Er. Wanbok,
As Respected Dr. NS Sir has been said that calculations shown in red is correct. Yes, It is correct for absolute volume only, but not for bulk volume. As suggested by Er. Jayakumar is correct method as bulk density is useful to convert weight to bulk volume.
Most practical method to convert weight to volume is that first of all wight quantity of FA & CA as per mix design, then fill standard box and decide proportion by volume.
Best Wishes,
B. V. Harsoda |
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es_jayakumar General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Thu Mar 21, 2013 1:53 am Post subject: |
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I attach details on how to work out the quantities in terms of volume.
- E S Jayakumar |
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es_jayakumar General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Sat Mar 23, 2013 1:40 am Post subject: |
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In continuation to the above topic, I attach a tabular format for finding out the corrections to be applied on the weights of moist aggregates and added water, when weigh batching is resorted to design mix concrete. This is taken from work site. Please note that entries in columns (7), (11) and (13) are as per the mix design recommendations.
E S Jayakumar |
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es_jayakumar General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Mon Mar 25, 2013 1:15 am Post subject: |
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Dear Er. Wanbok,
I hope you have worked out the design mix quantities in terms of volumes. Can you please share the proportions that you have arrived at along with details ? I am inquisitive about it.
Regards,
E S Jayakumar |
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es_jayakumar General Sponsor
Joined: 24 Nov 2011 Posts: 1408 Location: Cochin
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Posted: Mon Apr 01, 2013 1:27 am Post subject: |
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Dear Er. Wanbok,
Nothing is heard from you on my query. If the information provided by me is insufficient or incorrect, you think, please let me know, so that I can ponder it.
E S Jayakumar |
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wanboksutnga SEFI Member
Joined: 17 Mar 2013 Posts: 8
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Posted: Mon Apr 01, 2013 7:47 am Post subject: Regarding Conversion of Weight of concrete to Volume |
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es_jayakumar wrote: | Dear Er. Wanbok,
I hope you have worked out the design mix quantities in terms of volumes. Can you please share the proportions that you have arrived at along with details ? I am inquisitive about it.
Regards,
E S Jayakumar |
Dear Sir
As mentioned earlier that my mix design is by weight done by the Assam Engineering College that why i do wish to do the mix proportion at site by Volume because we donot have the Mixer Plant at site of construction.So regarding the details i will post it latter by scan copy.Also the proportion of mix design is as per given in my previous post shown in red colour |
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wanboksutnga SEFI Member
Joined: 17 Mar 2013 Posts: 8
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Posted: Mon Apr 01, 2013 8:02 am Post subject: Re: Conversion of Weight of concrete to Volume |
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Thanking you Sir for your responses
Dr. N. Subramanian wrote: | Dear Er Wanbok,
The first calculation, shown in Red is correct!
Best wishes,
NS
wanboksutnga wrote: | Dear Sefians
Kindly check the following calculation if it is correct or not because as per mix design the proportion is by weight but i want to do it by volume.Please help which one of the two calculation is correct.Mob-8974165540
As per mix design for M30
proportion=1:1.16:3.15
For cement=50 kg Sp G=3.15
Fa =58.05 kg Sp G=2.64
Ca =157.72 kg Sp G=2.68
In volume
For cement=50 kg =50/3.15/1000=0.0158 cum
Fa =58.05 kg =58.05/2.64/1000=0.0219 cum
Ca =157.72 kg =157.72/2.68/1000=0.0588 cum
Proportion by Volume=0.0158: 0.0219: 0.0588
=1:1.38:3.72
Box gauge to be used=250x250x250=0.0156 cum
Alternatively
50 kg of cement=50/1440=0.0347 cum==0.035 cum
Fa =58.05 kg =58.05/2.64/1000=0.0219 cum
Ca =157.72 kg =157.72/2.68/1000=0.0588 cum
Proportion by Volume=0.035: 0.0219: 0.0588
=1:0.63:1.68
Box gauge to be used=300x300x380=0.0347 cum |
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