Using Amorphous Magnetic Powder to Estimate the Depths of Cracks in Concrete

A new method is proposed for estimating the depth and inclination angle of a crack in concrete. Amorphous powders were packed into a crack and excited by means of an alternating magnetic field. The exciting field was created by an E-form ferrite core with a pick-up coil centered between the two exciting coils. The pick-up coil measured the magnitude and phase of the magnetic flux caused by the crack packed with amorphous powders. To model the crack, acrylic pipes of various lengths were prepared and packed with amorphous powders. The experimental results show that the inclination angle were clearly recognized, and the length of the crack was determined to be 30 mm.