Preparation of a novel foamed concrete modified with carbon fiber and graphite: Mechanical, electro-magnetic and microstructural characteristics based on X-CT
Qin-chuan Tu1,2, Qing-hui Xia1, Yao Lu1, Ying-hua Bai1,2*
1. School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, 430068, China
2.Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes, Ministry of Education, Hubei University of Technology, Wuhan, 430068, China
Abstract: In this paper, foam concrete is modified using graphite and carbon fiber as absorbents. The mechanical properties of the foam concrete are analysed in conjunction with hydration products, pore size distribution based on SEM test and XCT test. Further, the resistivity, complex permittivity and complex permeability are tested. The results demonstrate that carbon fiber enhance the proportion of pores with diameters less than 200µm in foam concrete, thereby substantially enhancing its flexural strength. Besides, adding graphite offsets the initial retardation of sulfoaluminate cement hydration induced by carbon fibers, which increases the average pore size of carbon fiber-reinforced foam concrete, reducing the compressive strength. The addition of carbon fibers at a concentration of 0.6wt.% achieves the percolation threshold, akin to scenarios with singular fiber incorporation. Exceeding 2wt% graphite content results in negligible influence on the conductivity of the carbon fiber-reinforced foam concrete. The synergistic integration of graphite and carbon fibers significantly enhances the electromagnetic wave absorption performance of the composite. At a thickness of 6 mm, the material exhibits an effective bandwidth where the reflection loss is less than -10 dB, extending up to 2.5 GHz, which constitutes 52.08% of the tested frequency spectrum.
Keywords: carbon fiber(D); X-CT(B); magnetic property(C)