How best to bond new concrete to existing?

[EdF_uk]

Hi,

I have some posts which I have concreted into the ground and I want to form a more decorative top so that soil will not be in contact with the post and water will run away. See the photo. Basically the blue part will be new concrete and I need to bond it to the bass already there.

Any suggestions?

Many thanks

E

 

[Bouy]

Scrabble old concrete is all you can.do

 

[tomfe]

Stick some sbr in your mix as well.

 

[Deluks]

It probably won't prolong the life of the posts, water will still get in and get trapped behind the concrete.
That said they are fairly chunky and should last quite a few years anyway.

An alternative would a timber 'skirt' around the base. You could paint the base of the post behind this with something oily like creocote (creosote substitute)