A molded concrete U-wall construction block including a molded concrete U-wall construction block structure formed from cured concrete poured about a block cage made from reinforcing material during a block manufacturing process. The block cage includes an open aperture formed in each of its stem reinforcing portions. During the block manufacturing process, the first and second support members of a support mechanism are inserted within the open apertures formed in the stem reinforcing sections of the block cage, and cooperate with the open apertures of the block cage so as to (i) support the block cage when being loaded into a block manufacturing machine, (ii) define central apertures molded in each stem portion of the concrete U-wall construction block structure, and (iii) lift the molded concrete U-wall construction block when being unloaded from the machine.

A permeable surface covering unit comprises a top surface, a bottom surface and at least two pairs of sides. A cavity is formed in the unit from the top surface to the bottom surface, and has side walls. The cavity may be a side cavity between units and/or a core cavity within the unit. An undercut is provided in the cavity. Pervious material plugs fill the cavity and extend into the undercut. Thereby the plug is locked into the cavity like a rivet and resists being dislodged by mechanical or hydraulic forces.

A mold and method for manufacturing interlocking concrete blocks. The mold comprises a mold box, comprising two side walls joined to end walls to define a mold cavity, a top face, and a substantially open bottom face. Top insert members are configured to define a space between adjacent blocks, for forming a portion of the transverse profile of the top surface of one block or a portion of the transverse profile of the bottom surface of an adjacent block, or both. A removable draw plate for closing the bottom of the mold box comprises a generally planar floor and bottom insert members configured to define a space between adjacent blocks, for forming a remaining portion of the transverse profile of the top surface of one block or a remaining portion of the transverse profile of the bottom surface of an adjacent block, or both.

A machine for and method of manufacturing concrete U-wall type construction blocks by molding each concrete u-wall construction block from concrete poured about a block cage made from reinforcing material while said block cage is loaded within the machine. The method involves providing a system of molding jacket panels, including a core molding assembly having a pair of inside stem jacket panels that are adjustably supportable in a substantially parallel manner during a molding process, and arranged is such a manner that the front wall portion is molded in downwardly facing direction toward a horizontal support surface and completely enclosed in one or more molding jacket panels. Before block molding operations, the thickness of the front wall portion of the U-wall construction block is set by determining the thickness of a front wall surface liner and installing the front wall surface forming liner within the system of molding jacket panels.