Abstract: A system for constructing concrete barriers on a roadway with adequate spacing between sections of the barrier for proper drainage and expansion of the concrete during changing atmospheric conditions. The process utilizes a specially designed positioning tool to leave a proper space in a latice framework of steel rods. A temporary, removeable core or separating section, made of for example a styrofoam inner layer sandwiched between outer layers of "Masonite," designed for this purpose and matched with the positioning tool is inserted into the space and secured there using pins attached to the metal latice works providing an unbroken, constant surface or mold on which to pour concrete for the barrier. When the concrete has set, the core may be collapsed without damaging the concrete or metal frame and removed. When the various cores are removed, the barrier is left with properly spaced and positioned gaps for drainage and expansion of the concrete.