What type of gravel to mix concrete?

[goldeagle]

I am planning to lay a new concrete floor soon and getting really confused by what gravel I should buy.

I am planning to mix it using cement, sharp sand and gravel (as opposed to using ballast) and already have the cement and sharp sand. I did get some 20mm gravel delivered but returned it as most of the gravel was larger than 20mm (not sure if that is normal for 20mm gravel) but it was no use for the concrete.

Looking at one website they sell Cotswald 20mm, 20mm round, 20mm chippings, 20mm clean - anyone have any idea what type of gravel I should be buying? Or doesn't it maater?

Appreciate any advise!

 

[Norcon]

Here in the province you just buy concrete mix which is basically sand and stones mixed up.
Which is bulk tipped into your trailer from the fork lift. Though you can buy it bagged now also.
Then a big navvy shovel to mix it up nicely.

 

[noseall]

I am planning to lay a new concrete floor soon and getting really confused by what gravel I should buy.

I am planning to mix it using cement, sharp sand and gravel (as opposed to using ballast) and already have the cement and sharp sand. I did get some 20mm gravel delivered but returned it as most of the gravel was larger than 20mm (not sure if that is normal for 20mm gravel) but it was no use for the concrete.

Looking at one website they sell Cotswald 20mm, 20mm round, 20mm chippings, 20mm clean - anyone have any idea what type of gravel I should be buying? Or doesn't it maater?

Appreciate any advise!

If you are confused about mixing concrete, why on earth did you buy separate materials? As Norcs said, it's simpler to buy 'ballast'.

You need 20mm gravel - simple as.

 

[goldeagle]

I'm not confused about mixing concrete, I'm confused as to what gravel I should get. The reason I bought separate is so that I could ensure I mix a specific 1:2:4 ratio mix. Most places you get ballast from you have no idea what the ratio of sand to aggregate is, so you will end up with an unknown strength of gravel.

 

[geraldthehamster]

I'm not confused about mixing concrete, I'm confused as to what gravel I should get. The reason I bought separate is so that I could ensure I mix a specific 1:2:4 ratio mix. Most places you get ballast from you have no idea what the ratio of sand to aggregate is, so you will end up with an unknown strength of gravel.

20mm gravel. The stuff you sent back. 20mm doesn't mean it's all 20mm, it's an approximate average.

Cheers
Richard

 

[noseall]

I'm not confused about mixing concrete, I'm confused as to what gravel I should get. The reason I bought separate is so that I could ensure I mix a specific 1:2:4 ratio mix. Most places you get ballast from you have no idea what the ratio of sand to aggregate is, so you will end up with an unknown strength of gravel.

What are you casting - an ornate statue or a poxy floor?

Regular ballast is rationed out at 4 parts gravel and two parts sand.