A stationary ring assembly forming a rotor shroud for a gas turbine, the stationary ring assembly comprising a plurality of segments having adjacent side faces that are placed end to end with sealing means interposed therebetween, the sealing means comprising at least one axial sealing strip and at least one radial sealing strip respectively received in axial slots and in radial slots formed facing one another in the adjacent side faces of the segments, at least one end of each radial slot opening out into the corresponding axial slot, each axial slot of a segment presenting a depth that is greater than the depth of the corresponding radial slot, and the axial sealing strip presenting a width that is greater than the width of the radial strip.