دانلود رایگان مقاله بررسی خواص الکترومغناطیسی و جذب مایکروویو مس سرباره توپر ملات سیمان

abstract

Ordinary cement mortar is a widely used structural material. However, its microwave absorbing ability is very weak due to the lack of magnetic and electrical conductive components. Copper slag is a by-product produced from copper smelting, which possesses excellent magnetic properties. In this paper, ordinary cement mortar specimens incorporated with copper slag were prepared. The electromagnetic (EM) parameters were determined by a network analyzer in 8.2e12.4 GHz frequency ranges. The reflectivity of the mortars against EM wave was evaluated through an arch reflectivity testing system in the same frequency ranges. The skin depth and compressive strength of mortars were calculated and tested, respectively. Results show that both the real and imaginary parts of permittivity increase with the increase of copper slag content and over 30% copper slag contents can evidently improve the permittivity of the mortars. Meanwhile, permeability of the mortars is evidently improved in the frequency ranges with the addition of the copper slag. The reflectivity values of the copper slag-filled mortars tend to decrease and then increase with the increase of copper slag contents. The minimum reflectivity reaches
13.4 dB and the reflectivity below
10.0 dB can be obtained in the frequency range of 8.2e8.4 and 10.4e10.9 GHz representing 90% absorption when the copper slag content is 50%. Over copper slag content can make the mortar not absorb but reflect the EM microwave. Skin depth decreases with the increase of microwave frequency and copper slag content. The mortars with 50% copper slag content exhibit higher compressive strength value, as well as better microwave absorption performance.

4. Conclusions

This is a preliminary study on EM parameter analyses and reflectivity evaluations of the copper slag-filled cement mortar. However, there are following results worth noting. a) Both the ε0 and ε00 of the specimens with copper slag are clearly higher than those without copper slag all over the frequency range. Permittivity increases with the increase of copper slag content and over 30% copper slag contents can evidently improve the permittivity of the mortar. b) Both the m0 and m00 of the specimens without copper slag are about 1.0 and 0. The complex permeability of the mortar depends on copper slag content. After the copper slag is incorporated, both the m0 and m00 values are evidently enhanced in the frequency range. c) The electrical conductivity of the mortars evidently increases with the increase of copper slag content. In addition, the skin depth decreases with the increase of microwave frequency and copper slag content.d) The mortar exhibits mainly reflection performances in the frequency range of 8.2e12.4 GHz below the copper slag volume mass fraction of 30%. The minimum reflectivity reaches
13.4 dB at the matching frequency of 10.6 GHz when the copper slag content is 50%. Whereas, when the copper slag content reaches 70%, the reflectivity values are greater than
10.0 dB and the mortar begins to reflect the wave. e) Optimum copper slag content is the key to achieve high EM wave absorption and compressive strength for the copper slag-filled cement mortar. The mortars with 50% copper slag content exhibit higher compressive strength value, as well as better microwave absorption performance.