Thick Bed slow set exterior tile adhesive

[physco]

I am looking for a slow setting and long workable plymer modified thick bed adheisve for fixing some concrete slabs to a concrete pad. Most I have seen seem to have a 'use time' of 20 to 45 mins and I was hoping there is something that lasts longer than this so I dont have to work to quickly and make a bocth up. Its only a small area I am laying but it need to be very very flat as it will have a hot tub on.

Any suggestions welcomed - prefereably nothing to expensive.

 

[r896neo]

why not use mortar?

 

[Maxsys]

Not sure if this will do it, but can be laid up to 12MM thick, external grade, solid bed and has a three hour pot life sets in 24hrs

http://www.tileadhesive.co.uk/#Flexible CFTA