Concrete v cement

[nickk]

just curious,what are the different shrinkage/strength rates for a footing say for a gate post size hole. Thanks.

 

[mtt.tr]

This might be helpful
https://www.baseconcrete.co.uk/different-types-of-concrete-grades-and-their-uses/

Nearly everything i use is mixed near c20- c25

 

[Shox Dr]

Do you mean; concrete v Motar.

Water causes the shrinkage, use the least amount possible. Keep it covered for a week or so

 

[nickk]

Do you mean; concrete v Motar.

Water causes the shrinkage, use the least amount possible. Keep it covered for a week or so

Yes ,mortar.

 

[Dcal]

How much cement you need in a mix is dependant on the amount and size of the particles in the aggregate as well as the type of cement being used.
The smaller the particles the more cement you need to coat them.
All things being equal you need less cement for bigger aggegeriate (concrete)
However if you only use large aggregate the mix isn't dense and you will get voids which also isn't good and will reduce the strength of the mix.
That is why concrete and to alesser extent mortor. is a blend of large aggegeriate (normally crushed stone) and fine (sand). The distribution of grain sizes and quantity in all the aggegeriate is controlled to give the type of concrete required.

If mortor is made with the same ratio of cement to very fine sand and another batch of sharp sand the sharp sand mix will be much stronger.
It's the reason the gulf states have to import all their sand for building.
They have plenty of sand just the wrong sort.

 

[Pete.]

Mortar has little or no tensile strength. If you bed a post in with mortar it'll just disintegrate. Use concrete.

 

[Dcal]

Pete, a "bit" more concise than my ramblings but basically saying the same thing.

 

[brightspark]

buy a bag of postcrete shot some water in hole and just pour the bag in and podge it job done