吸波功能集料混凝土的制备与性能研究

发布时间：2018-04-03 13:31

本文选题：吸波混凝土　切入点：功能集料　出处：《武汉理工大学》2015年硕士论文

【摘要】：随着科学技术的迅速发展,电磁辐射造成的“电磁污染”被列为继大气污染、水源污染、噪声污染之后的第四大环境污染。吸波混凝土是一种多功能型建筑材料,能吸收、衰减入射的电磁波,并将电磁波能量转化为热能或其它形式能量损耗掉,在电磁干扰的防护、电磁信息的保密和减少辐射伤害等方面具有广阔的应用前景。现有的吸波混凝土存在吸收效能低、吸收频带窄、结构功能性差和价格昂贵等问题,使其难以大规模应用到建筑物的电磁防护中。本文依托国家自然科学基金项目,针对传统吸波混凝土中无吸波性能集料占据混凝土体积大部分,影响混凝土中吸波功能组分的掺量及空间分布的问题,开展了包括集料在内的完整吸波功能结构混凝土的设计与制备方法的研究,为高性能吸波混凝土材料的设计与研究提供了新的思路。本文进行的主要研究工作和取得的成果如下:依据电磁波吸收原理,设计出具有吸波功能的集料,在此基础上结合水泥混凝土材料自身特征,提出兼顾吸波性能和力学性能的高性能吸波功能集料混凝土的设计方法。通过掺膨胀珍珠岩改善混凝土表面的阻抗匹配,损耗层中吸波功能集料均匀分布在混凝土中起到吸波及承重作用,与掺吸波剂的水泥浆体形成完整吸波功能结构混凝土。以二氧化钛为吸波剂,粘土为基体材料,经过原料预处理、造粒和煅烧等工艺制备吸波功能集料。研究吸波剂的掺量、煅烧制度对吸波功能集料物理性能的影响,确定了吸波功能集料的制备工艺,制备出兼顾吸波性能和强度性能的吸波功能集料。用烧制的功能集料制备吸波混凝土,测试混凝土吸波性能和力学性能。结果表明,集料种类、匹配层和试样厚度对混凝土吸波性能有较大的影响。掺30%TiO2的功能集料制备的混凝土吸波性能最佳,当双层混凝土厚度为20mm时,在8~15GHz频段内,反射率均小于-8dB;双层混凝土厚度为30mm时,在高频处吸波效能较好,在18GHz处最小反射率值达-9.0dB,混凝土28d抗压强度为35.5MPa。用掺30%TiO2的吸波功能集料分别与高结构炭黑、铁氧体和纳米二氧化钛共同制备复合吸波功能集料混凝土,研究表明,功能集料与不同种类吸波剂复合使用,混凝土的吸波效能较好,吸波频带较宽,具有较好的力学性能。特别是与锰锌铁氧体使用,锰锌铁氧体掺量为30%的双层混凝土,当厚度为20mm时,在8~15GHz频段内,反射率小于-10dB吸收频带达8.7GHz,最小反射率为-14.7dB,且强度能满足一般建筑物对混凝土强度要求。
[Abstract]:With the rapid development of science and technology, electromagnetic pollution caused by electromagnetic radiation has been listed as the fourth major environmental pollution after air pollution, water pollution and noise pollution.Wave absorbing concrete is a kind of multifunctional building material, which can absorb and attenuate the incident electromagnetic wave, and convert the electromagnetic wave energy into heat energy or other forms of energy loss, so as to protect against electromagnetic interference.The secrecy of electromagnetic information and the reduction of radiation damage have broad application prospects.The existing absorbing concrete has some problems such as low absorption efficiency, narrow absorption band, poor structure function and high price, which makes it difficult to be applied to the electromagnetic protection of buildings on a large scale.Based on the project of the National Natural Science Foundation of China, this paper aims at the problem that the non-absorbing performance aggregate occupies the bulk of the concrete in the traditional absorbing concrete, which affects the content and spatial distribution of the absorbing function component in the concrete.In this paper, the design and preparation method of the complete absorbing structure concrete, including aggregates, is studied, which provides a new idea for the design and research of the high performance absorbing concrete material.The main research work and results obtained in this paper are as follows: according to the principle of electromagnetic wave absorption, the aggregates with absorbing function are designed and combined with the characteristics of cement concrete materials.The design method of high performance absorbing function aggregate concrete with both absorbing and mechanical properties is presented.By adding expanded perlite to improve the impedance matching of concrete surface, the wave absorbing functional aggregate in the loss layer distributes uniformly in the concrete and plays the role of absorbing wave and bearing weight, and forms the complete absorbing function structure concrete with the cement paste mixed with the absorbing agent.Using titanium dioxide as absorbent and clay as matrix material, microwave absorbing functional aggregates were prepared by pretreatment of raw materials, granulation and calcination.The effects of the amount of absorbent and the calcination system on the physical properties of absorbing functional aggregates were studied. The preparation process of absorbing functional aggregates was determined and the absorbing functional aggregates with both absorbing and strength properties were prepared.The wave absorbing concrete was prepared with the sintered functional aggregate, and the absorbing and mechanical properties of the concrete were tested.The results show that the type of aggregate, matching layer and sample thickness have great influence on the absorbing property of concrete.When the thickness of double-layer concrete is 20mm, the reflectivity is less than -8 dB in the band of 8~15GHz, and when the thickness of double-layer concrete is 30mm, the absorbing efficiency of double-layer concrete is better at high frequency.The minimum reflectance at 18GHz is -9.0 dB, and the compressive strength of concrete is 35.5MPa at 28d.The composite absorbing functional aggregate concrete was prepared by using 30%TiO2 doped functional absorbing aggregate and high structure carbon black, ferrite and nano titanium dioxide respectively. The results showed that the functional aggregate was used in combination with different kinds of absorbing agents.The concrete has better absorbing efficiency, wider absorbing band and better mechanical properties.Especially for the use of Mn-Zn ferrite, when the thickness of Mn-Zn ferrite is 30%, when the thickness is 20mm, in the 8~15GHz band,The reflectivity is less than -10dB and the absorption band is 8.7 GHz, the minimum reflectivity is -14.7 dB, and the strength can meet the concrete strength requirement of general buildings.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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