Abstract: A rotating cutting blade and its drive motor are mounted on a wheeled support platform. The blade extends through a skid plate depending from the platform, in order to cut the concrete below the skid plate. The slot in the skid plate has its ends configured to fit within predetermined distances of the corresponding ends of cutting segments on the cutting blade. The cutting segments are configured to have a generally inverted "T" configuration in which a central cutting segment extends radially outward from two cutting segments located on opposite sides of the central segment. The exterior edges of the cutting segments may be square or rounded. The juncture between the central and shoulder segments may be square or rounded. The concrete is advantageously cut before it hardens to 1200 psi, without the use of an added lubricant, or above that hardness with lubricant if the cutting blade is supported within a sufficiently close distance by a skid plate.