The aggregate move to the center of the tube when concrete placed with the pump car. The material separates when this becomes awful. The device from which this separation was prevented was developed. This is installed in the boom point of a concrete pump car. The presence of MY-BOX was assumed to be an experiment variable, and the comparison experiment of concrte properties was done. When this device is used, the material becomes uniform. Workability improves and the quality improves. The crack of the foundation decreases. The air gap on the surface of the foundation decrease. The speed of making to the carbonation is slow.
