Cast Concrete arch bridge

 

Picking back up on a much earlier post, I finally started casting my concrete arch hydrocal bridge in two halves.

_MG_8797sm

Wood & Sintra Mold

My waxed wood and sintra casting form

_MG_8794sm

Wood & Sintra mold showing thickness

Pouring hydrocal with steel rod reinforcements

_MG_8842sm

Pouring requires working quickly as Hydrocal sets fast

Leveling  to the face of the form

_MG_8852sm

Level as close to flat as possible

Exterior pieces of the form being removed

_MG_8895sm

Exterior parts remove easily

Casting removed from the mold and flipped over, with only the individual small arch pieces to be removed. These pieces have a 3 degree slope for ease of getting them out of the piece.     Still required a few knocks with a small hammer on each to remove!

_MG_8896sm

Casting lightly sanded at this point

First half cast, but I’ll add some detailing with a file, forming casting joints and other details, then cast the other half and place them back to back, with a spacer which is typical for this type of bridge, really two identical arches, connected at the top.

_MG_8903sm

Casting before final detailing