Not sure if it would work but you could try a hand planer in a bench configuration (i.e. upside down ) and you pass the pieces over the blade using it like a thicknesser. A thicknesser could probably do the job faster as long as the bitumen doesn't affect the blades.
Not sure if it would work but you could try a hand planer in a bench configuration (i.e. upside down ) and you pass the pieces over the blade using it like a thicknesser. A thicknesser could probably do the job faster as long as the bitumen doesn't affect the blades.