Abstract: Apparatus for removing structural concrete comprises an elongated hood having an inner generally non-accessible zone, an outer zone accessible for performing maintenance functions and an elongated slot between the zones. A reciprocal feed carriage is guidably mounted within the hood in the inner zone and mounts a seal support housing within the outer zone. Portions of the housing extend through the slot into the inner zone and are pivotally mounted upon the carriage. A rotating shaft and seal assembly is mounted upon the seal support housing in the outer zone, including a body having a water inlet adapted for connection to a source of water under pressure. An elongated tubular shaft and nozzle assembly is axially connected to the rotatable seal and shaft assembly and extends from the seal support housing through the slot into the inner zone of the hood, through the carriage and into the bottom of the hood for directing water under pressure against the structural concrete.