石墨泡沫混凝土的吸波性能研究

多功能化和低成本有利于建筑吸波材料的应用。在频率8～18GHz范围内,采用弓形反射法测试了掺加石墨的水泥基泡沫混凝土的吸波性能,研究了石墨掺量、发泡剂用量和试件厚度对石墨泡沫混凝土吸波性能的影响。结果表明,掺加石墨后,泡沫混凝土吸波性能逐渐增强,石墨泡沫混凝土吸波材料中石墨的逾渗阈值为水泥质量的15%;随着发泡剂用量增加,石墨泡沫混凝土反射率逐渐降低。厚度为30mm时,泡沫混凝土吸波性能最佳,当石墨掺量和发泡剂用量分别为水泥质量的15%和2.5%时,反射率降低至-15.64dB,<-10.0dB的带宽可达3.0GHz,导热系数低至0.083W/(m.K)。石墨泡沫混凝土具有良好的保温和吸波性能,可以浇注施工建筑物的屋面和墙体,同时实现建筑电磁辐射防护和建筑节能的目标。

Microwave absorbing property of the graphite foam concrete

The multi-functional property and lower cost are the main factors which decide the application pro-spects of building microwave absorbing materials.At 8-18GHz,the microwave absorbing property of the graphite foam concrete was tested by bow reflection method,and the effect of graphite dosage,foaming agent dosage and specimen thickness on absorbing property were tested at same time.The results showed that the absorbing property of foam concrete increased gradually with increasing of the graphite content,the percolation threshold of graphite in the graphite foam concrete was 15% of cement content.The reflectivity of foam concrete decreased gradually with increasing of the foaming agent dosage.The absorbing property of foam concrete reached high-point when the specimen thickness was 30mm,the reflectivity minimum value of foam concrete was-15.64dB when the graphite content and foaming agent dosage were 15% and 2.5% of cement content,respectively,and the total bandwidth was 3.0GHz when the reflectivity was below-10.0dB,at the same time thermal conductivity of foam concrete as low as 0.083W/(m·K).Graphite foam concrete has good thermal insulation and absorbing performance,which can be used to build the roofing and wall by cast construction,and then the target of building electromagnetic radiation protection and building energy was achieved at the same time.