The twin-shaft mixer ensures the production of evenly mixed concrete, and high-demand concrete can be made for special applications. The mixing chamber is protected by high-strength shielding that can be replaced when worn, as well as the mixing fins and arms which are screwed onto the shafts. Evacuation of the concrete is done by a door hydraulically driven by an oil pressure pump. The hydraulic circuit provides the possibility of manual evacuation of the concrete in case the power supply is interrupted. The discharge hopper is made of 5mm thick sheet metal and has a vibrator 200kgf, at 3,000min-1, 260Watt, for the discharge of concrete. The mixer has a circular inside the pipe that empties the water.