TiO2 containing electromagnetic wave absorbing aggregate and its application in concrete

- The concept of electromagnetic wave absorbing functional aggregate is proposed for the first time.
- TiO2 containing electromagnetic wave absorbing functional aggregate was prepared.
- Microwave absorption of the functional aggregate is largely due to the dielectric loss effect of TiO2.
- The TiO2 containing functional aggregate obviously improved the microwave absorption of concrete.

The concept of electromagnetic wave absorbing (EMWA) functional aggregate used in concrete is proposed for the first time. It was prepared by dispersing TiO2 powder into clay and then calcining. The electromagnetic wave absorbing ability of concrete prepared with the functional aggregate was markedly improved compared to concrete with gravel aggregate or ordinary haydite aggregate. Further improvement is found to be realized by the addition of manganese zincferrite powder into cement paste. The absorption bandwidth below −10 dB was larger than 8 GHz in the tested range of 8-18 GHz. Moreover, the compressive strength of concrete (water/cement ratio = 0.4) prepared with functional aggregate was higher than 28 MPa at 28 days and it can be used directly as a structural component in buildings.