Hello.
I am planning to mix my own concrete and am wondering how important the grain sizes in the aggregate are. Can I increase the cement content a little? I was thinking of 300kg/m3.
The question arises because I wonder if I can use my own gravel or if I have to buy everything from the pit.
If I use my own gravel, there will be a lot of varying sizes of the grains/stones. Approximately 0-50mm.
Then I have some crushed stone that I am considering using, possibly, I think it's 0-35, maybe a little coarser, but it's coarse road gravel anyway.
And if I am going to buy from the "pit," what should I order and in what proportions?
Grateful for any tips.
I am planning to mix my own concrete and am wondering how important the grain sizes in the aggregate are. Can I increase the cement content a little? I was thinking of 300kg/m3.
The question arises because I wonder if I can use my own gravel or if I have to buy everything from the pit.
If I use my own gravel, there will be a lot of varying sizes of the grains/stones. Approximately 0-50mm.
Then I have some crushed stone that I am considering using, possibly, I think it's 0-35, maybe a little coarser, but it's coarse road gravel anyway.
And if I am going to buy from the "pit," what should I order and in what proportions?
Grateful for any tips.
Be careful not to include too much "0", i.e. fine mtrl, in the ballast. Then it requires much more cement to achieve the same strength of the concrete.
The cement bags often have recipes on them - follow them!
The cement bags often have recipes on them - follow them!
By "0" you mean stenmjöl I assume? I have heard that it doesn't affect the need for cement or water. I am going to mix quite a few cubic meters so it would be good if you could add a bag of cement and then take most of the ballast from material you already have, avoiding having to deal with a lot of different piles, then it might be worth using a slightly larger bag for the cement.
Or should you just go with natural gravel and buy some specific screened fraction?
Or should you just go with natural gravel and buy some specific screened fraction?
Possible,
But of course there was more cement when it came to stone flour, but a couple of kilos (5-10) more or less I didn't think was that much.
Might as well throw in an extra 25-kilo bag in each batch...
or increase the proportion of naturgrus, but that was kind of why I asked, if unscreened (more or less) naturgrus works satisfactorily. It should be for a slab and some plinths.
Or buy all the ballast...
But of course there was more cement when it came to stone flour, but a couple of kilos (5-10) more or less I didn't think was that much.
Might as well throw in an extra 25-kilo bag in each batch...
or increase the proportion of naturgrus, but that was kind of why I asked, if unscreened (more or less) naturgrus works satisfactorily. It should be for a slab and some plinths.
Or buy all the ballast...
I have cast some parts where I used 0-8 crushed stone instead of natural gravel together with 8-16 and yes, you have to modify the recipe a bit for it to become sticky enough 
.
I've also cast with pre-crushed 0-18 and even there you want to add an extra shovel of natural gravel or two to get a better consistency overall.
This has been for some retaining walls and similar, so I haven't needed such high strength.
.I've also cast with pre-crushed 0-18 and even there you want to add an extra shovel of natural gravel or two to get a better consistency overall.
This has been for some retaining walls and similar, so I haven't needed such high strength.
depends entirely on the gravel's dimensions and if it's moist....
adding to the right consistency is good...start with about 80-90 liters.
If you're going to cast a lot, you should do it right from the beginning, otherwise, you'll have to redo it later when it cracks and freezes apart.
Contact a professional if you're unsure...
adding to the right consistency is good...start with about 80-90 liters.
If you're going to cast a lot, you should do it right from the beginning, otherwise, you'll have to redo it later when it cracks and freezes apart.
Contact a professional if you're unsure...
The "pros" probably get their btg in the car.. Will probably have to buy the ballast out of necessity. The cement costs about 250kr per batch and roughly a cubic meter of ballast I estimate to be around 200. About 500kr per cubic meter then, quite okay if that calculation holds, about 7-800 cheaper than purchased btg.. Already 2 cubic meters per hour becomes a decent saving..