fire door slamming has loosened frame

[skybluescooby]

My kitchen to garage fire door has always caused me problems by its constant slamming, previous owners obviously didnt care as the frame has become loose.
Now i have fixed three frame fixing bolts down the lock side of the jamb but still its loose, The problem i have is that its fixed to some very light breeze blocks, the ones you can push a screwdriver into.
The gap between the frame and the block is becoming bigger as bits of the block are falling off garage side.
whats the best way to cure this, i have tried covering the crack with smooth filler but its now falling off due to irregular slamming,
The crack varies from 2mm up to 4" in places,
Would a flexible foam filler solve the problem ???
Any ideas would be very welcome as the plasterboard, kitchen side is becoming loose now.
Regards

 

[masona]

Remove the architrave if you have them, then break some of the celcon block just behind the door frame on both side then make good with sand/cement, make sure the cement is hard before usng the door again.
You can use door packing wedge shape but cement is better.

 

[skybluescooby]

Cheers
What mix would be the strongest and most workable ??
No architrave , just a 2"frame fixed with wall bolts

 

[masona]

1 part cement, 3 parts sand

 

[skybluescooby]

just an update, tried the cement trick but due to wind tunnel type effects when garage and back door are open the cement just cracked and fell away.
I tried expanding foam and its done a cracking job, only thing i noticed was the frame was bowing out so i jammed a length of wood between the two uprights and its strong as anything thats really strong