CONCRETE COLUMN FORMING TUBE

摘要

CONCRETE COLUMN FORMING TUBE Of The Invention A concrete column forming tube is provided for receiving poured concrete therein to produce a concrete column and which is characterized by producing improved surface characteristics on the concrete column including a matte finish without seam lines of the forming tube. An improved flexible cylindrical liner is positioned in a generally friction-fit relationship within an elongate rigid cylindrical tube constructed of partially-overlapped spirally-wound plies of paper adhered together and defining an inside wall surface having spiral seam lines thereon. The improved flexible liner is constructed of a convolutely-wound paperboard layer secured at butted edges and having an inside wall surface of desired paper fiber matte texture and a thickness sufficient to bridge and cover the spiral seam lines on the inside wall surface of the rigid tube to prevent the formation of seam lines on the outside surface of the produced concrete column. A thin plastic coating layer is laminated to the inside wall surface of the paperboard layer and has a thickness sufficiently thinner than the paperboard layer so that the plastic coating layer assumes the desired paper fiber matte texture of the inside wall surface of the paperboard layer to produce a concrete column with a matte finish on the outside surface.