多孔集料砂浆的吸波特性

Absorbing Properties of Cement Mortar Filled with Porous Aggregates

对发泡聚苯乙烯、膨胀珍珠岩、页岩陶粒等3种多孔集料填充水泥基复合材料的电磁波吸收性能进行了研究。结果表明:多孔集料提高了复合材料与自由空间的波阻抗匹配程度,还可引起电磁波多次反射和散射,从而使电磁波迅速衰减;多孔集料填充率、集料种类、集料粒径等对电磁波吸收性能有显著影响;选用的多种集料中发泡聚苯乙烯对复合材料吸波性能的改善最为明显,当发泡聚苯乙烯粒径为2mm、与水泥体积比为1:1时,试样在4.5GHz处有最小反射率-18dB,且小于-10dB的吸收带宽达8.1GHz。

The absorbing properties of cement mortar filled with porous aggregates, such as expanded polystyrene, expanded perlite and shale, were investigated. The results show that porous aggregates can improve the impedance matching characteristic of the composites, and attenuate the electromagnetic wave by mulitple scattering and reflection. The filling ratio, the type and the size of porous aggregates all had effects on the absorbing properties. Among the aggregates used, the expanded polystyrene （EPS） had a superior ability to improve the absorbing properties of cement composite. When the filling ratio of EPS with the size of 2 mm to cement was 1：1 in volume, the lowest reflectivity of-18 dB was obtained at 4.5 GHz and the bandwidth less than -10 dB was 8.1 GHz.