Casting with pipe trench gravel instead of concrete gravel?

[Saxpy]

I ended up with a rather large amount of trench gravel left over that's just "lying around" on the property.

Is it suitable to use it instead of concrete gravel when mixing your own concrete?

 

[Fotografen]

I actually don't know a jot about concrete, but it depends a bit on what you're casting. A foundation for the sundial or the clothesline might be okay to experiment with a bit, but not the flagpole or piers for a house.

 

[Saxpy]

I am going to make a crawl space with leca foundation blocks. However, it is on rock and it will protrude between some of the foundation blocks, so I was thinking of filling it with concrete there. It's not a large amount, so I could of course buy a few bags of coarse concrete, but now I had all the ingredients at home, so it would be practical to be able to use them.

 

[MathiasS]

Yes, it's going well. A bit of an incorrect gradation curve, but for example, at vårbykrossen where I usually pick up, they don't even have concrete gravel but refer to trench gravel. If you ask a real cement guy, it's a deadly sin with an entirely unpredictable outcome, but in practice, your mix won’t become noticeably worse. Throw in a bit of extra cement to compensate for possibly having too much fine material.

 

[Saxpy]

Sounds good.

 

[jens71]

Do not do it, it should be at least 8 mm, preferably 16 - 32 mm gravel and washed so the cement can bind together in the best way.

 

[-RB-]

Have never heard of washed cast gravel. It should be free from humus, but washed?

 

[MathiasS]

Don't do that, it should be at least 8 mm, preferably 16 - 32 mm gravel and washed so the cement can bind together in the best way.

You're mixing things up. Concrete gravel is 0-8, just like trench gravel. Then you use something coarser as aggregate, like 8-16 macadam. If you want larger stone, that works, but for small castings you'll have problems with the stones wedging in, etc....

Washed macadam is good, but don't think it makes any difference in quality when mixing by yourself.

 

[MaxPax]

Pour, just pour!