Concrete pavers for the manifold?

Hello,

I'm trying to build my first RMH. I'm a bit short on fire bricks and getting more requires a pretty long trip.
I do, however, have access to a bunch of salvaged concrete paver bricks.
Can this be used to build the manifold (and in case I'm using that term incorrectly, which I might be, by manifold
I mean the brick structure that holds the barrel and which also has the start of the stove pipe for carrying out hot gases
to the thermal mass)?

I'm building a 6-inch system and I'm using a relatively small boiler which needs to be lifted off the ground quite a bit
in order to accommodate the 47" heat riser (Ernie and Erica's Annex plans). If concrete pavers can be used,
that'll save me a bunch of time and money.

Thanks,

Daniel Granovsky

only the rocket core and riser really need to be refractory. everything else can be lower temp material and standard portland cement may be used in that area.