# Anyone know about concrete, weight?



## Lsmcdti (Aug 14, 2015)

Going to make some weights from concrete, will a 20kg bag of concrete mix weigh 20kg once mixed with the water and set ? Thanks


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## GeeWhizRS (Nov 1, 2019)

If you took a 20kg bag of concrete mix and just opened the bag it would start to absorb moisture from the air and gradually start to weigh more than its initial 20kg. I don't know the figure you're looking for, but if you add water to 20kg of concrete mix it will obviously weigh heavier and then gradually evaporate and lose weight; although you will only lose so much. It will never be as dry and therefore the same weight as the unopened product. Does it need to be that accurate?


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## Caledoniandream (Oct 9, 2009)

1 cubic meter set concrete is approx 2 ton.
20 kg of concrete mix if nothing added will weigh approx 20 kilo, it will retain a little bit water, but you can ignore that. 
If you make weights with them I would use some re-enforcement, so if you drop it, it doesn’t shatter in several pieces.


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## bluechimp (Dec 21, 2017)

No it will weigh more as some of the water will ‘hydrate’ the concrete. Typically around 60% of the water used. So as a very rough calculation around 2 litres of water is required to mix 20Kg of concrete. 2l = 2kg at 4deg so 60% is 1.2kg so it will roughly weigh 21kg.

This is all hypothetical and if it’s for anything crucial I really would calculate it properly.


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## kingswood (Jun 23, 2016)

Get some plant pots and a piece of bar. Fill plant pots and put bar in the middle. 

Use small, medium and large plant pots. And then get the scales out. 

I’ve concreate plastic coated weights and a pasta size dish of weight is 7.5kg. 

Rekon 40kb dumbells will be to big to use. 

I’d wrap what u Male in gorilla tape so they don’t chip

Let us know how u get on 


Sent from my iPhone using Tapatalk


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## Lsmcdti (Aug 14, 2015)

Caledoniandream said:


> 1 cubic meter set concrete is approx 2 ton.
> 20 kg of concrete mix if nothing added will weigh approx 20 kilo, it will retain a little bit water, but you can ignore that.
> If you make weights with them I would use some re-enforcement, so if you drop it, it doesn't shatter in several pieces.


What could be used to reenforce it ? Thanks


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