Abstract: Hollow-core construction blocks are superposed without intervening mortar. The hollow-core construction blocks are provided with vertical, longitudinally spaced cylindrical apertures. Vertical slots having the same spaced relationship are interposed between the vertical apertures. Both the vertical apertures and the vertical slots open at one side of the block in a longitudinal channel having an at least approximately semi-circular cross-section. These building components permit forming arbitrarily high walls by the "dry", i.e. without mortar, superposition of the construction blocks and pouring concrete into the cylindrical vertical apertures of an upper row of blocks. The concrete flows downward, perhaps with the aid of a vibrator, and spreads out in lateral direction through the longitudinal channels. The vertical slots provide a means of escape for the displaced air.