Abstract:In order to improve electromagnetic wave absorbing properties of asphalt pavement, the asphalt mixture samples were prepared using natural magnetite powder as absorber. The electromagnetic parameters such as complex dielectric constant and complex magnetic permeability of samples with different replacement rates of natural magnetite powder were tested by the method of rectangular waveguide. Reflection loss of samples were calculated based on the transmission line and impedance theory. Results show that with addition of natural magnetite powder, electromagnetic parameters of asphalt mixture are improved significantly. With the increasing grade and increasing replacement rate of natural magnetite powder, the real part of the complex dielectric constant is significantly increased while the imaginary part has little change. Both the real and imaginary parts of complex magnetic permeability are increased with the increasing grade and increasing replacement rate of natural magnetite powder. Asphalt pavement with reflection loss of less than -10dB can be prepared by adding natural magnetite powder in grade of 60 and above. There are three kinds of matching thickness (3,5,7cm) of electromagnetic wave absorbing asphalt pavement during 211cm. The recommended design value of asphalt pavement thickness is 3cm. When the designed thickness of pavement layer is higher than 3cm, the lower replacement rate of natural magnetite powder should be selected.
