What's the difference between subbase and ballast?

[adamr7747]

And can I just use one dumpy bag (e.g. this or this) for both mixing concrete and the base it sits on?

(This will be for a small (1.2m x 1.0m) pad to support some blocks with an IBC full of rainwater on top.)

Thanks a lot,
Adam

 

[imamartian]

... after a bit of googling (and i'm a DIYer not a pro..) i found this:

The proportions of materials for a C20P (P = Portland cement) mix are 1 x cement, 2 x fine aggregate (sand) and 4 x coarse aggregate. If you are using premixed ballast, then 6 of these are mixed with 1 part cement.

so go for the ballast....

 

[adamr7747]

Thanks, but how did you find out what's in the ballast? And can it be used as a sub-base and if so, why does anyone buy the MOT1? And if not, how come? Surely they're both just a mixture of gravel and sand?

Thanks
Adam

 

[Spr0cket]

The MOT material tends to interlock much better than standard ballast does. Hence Ballast typically has to be used with a binder (Cement) to form a stable or strong base / material. The stones in gravel tend to be rounded and don't self bind, whereas MOT material tends to have straighter edged particles that do set up against each other. MOT whilst not strong by itself for any direct traffic does an excellent job as a base layer.

I likely did a cr&p job of trying to convey that so have a read of this for a much better overview and details:

http://www.pavingexpert.com/subbase.htm

 

[adamr7747]

Thanks, that's helpful

 

[r896neo]

short answer, don't use ballast as a sub-base, it's not suitable.