Abstract: A mold system for casting five-sided, monolithic, seamless concrete products comprises an outside jacket, an inside mold core complete with base, and a movable pallet to aid stripping. The outside jacket preferably includes two L-shaped panel members arranged in a rectangular configuration which are supported for movement between open and closed positions by a pair of base-mounted corner actuators extending from the fixed base to the apex of each panel member. The panel members are also linked to one another by a series of actuators along each of the adjoining two corners of the jacket. The inside core includes four interior panels linked by four inside retractable corners. A minimum of two series of actuators also span the middle portion of the inside core. These middle actuators in conjunction with the actuators in the corner devices function to expand and contract the entire inside mold core. A plurality of base supported actuators are fastened to the inside core.

Abstract: A plastic liner for protecting concrete manhole interior surfaces from corrosion wherein the liner includes provisions for creating a strong mechanical lock between the liner and the interior surfaces. A side of the liner which includes the provisions has a plurality of raised hollow projections with spaced sections. The mechanical lock is created when concrete is poured against the side of the liner with the projections. The concrete at least partially enters the hollow portions and fills spaces between the projection sections. The projections also intersect to enhance the mechanical lock by preventing bulging. Liner sections cover essentially all of the manhole interior surfaces. Forming a liner section by rotationally molding the plastic and cutting gaps into the projections is also disclosed.

Abstract: A plastic liner for protecting concrete manhole interior surfaces from corrosion wherein the liner includes provisions for creating a strong mechanical lock between the liner and the interior surfaces. A side of the liner which includes the provisions has a plurality of raised hollow projections with spaced sections. The mechanical lock is created when concrete is poured against the side of the liner with the projections. The concrete at least partially enters the hollow portions and fills spaces between the projection sections. The projections also intersect to enhance the mechanical lock by preventing bulging. Liner sections cover essentially all of the manhole interior surfaces. Forming a liner section by rotationally molding the plastic and cutting gaps into the projections is also disclosed.

Abstract: A plastic liner for protecting concrete manhole interior surfaces from corrosion wherein the liner includes provisions for creating a strong mechanical lock between the liner and the interior surfaces. A side of the liner which includes the provisions has a plurality of raised hollow projections with spaced sections. The mechanical lock is created when concrete is poured against the side of the liner with the projections. The concrete at least partially enters the hollow portions and fills spaces between the projection sections. The projections also intersect to enhance the mechanical lock by preventing bulging. Liner sections cover essentially all of the manhole interior surfaces. Forming a liner section by rotationally molding the plastic and cutting gaps into the projections is also disclosed.

Abstract: An inside corner form for forming an inside corner of a wall structure for casting concrete includes a central member for forming the corner, side members for forming portions of the walls adjacent the corner, an actuator for expanding and contracting the inside corner form and a lid for five sided pours. Slide lugs are provided to engage the central and side members such that the members are maintained in their proper orientations, while still permitting the members to slide relative to one another during the expansion and contraction of the form. A flowable material is injected between the central and side members for lubrication and to form a barrier to prevent grout from seeping between the members of the inside corner form and lid.