【作者】 易小顺；

【导师】 黄少文；

【作者基本信息】 南昌大学 ， 材料物理与化学， 2011， 硕士

【摘要】 在建筑物中应用电磁屏蔽材料是现代建筑设计的一个新内容。水泥基电磁屏蔽材料具有成本低廉、施工方便、防护面积大的优点,因此其未来市场前景将十分广阔。本文研究了废轮胎钢丝作为导电剂掺入水泥浆体中对材料力学性能、电学性能和电磁屏蔽性能的影响。研究了废轮胎钢丝水泥基材料的制备工艺；探讨了废轮胎钢丝对水泥浆体工作性能的影响；用四电极法测定了材料的导电性能；采用同轴法兰—频谱分析仪法探讨了废轮胎钢丝体积掺量、养护龄期、养护条件、钢丝与石墨(超导电炭黑)复掺等因素对材料电磁屏蔽性能的影响。研究表明,掺废轮胎钢丝水泥基材料的屏蔽性能及导电性能要优于掺等量普通平直钢纤维的材料。与掺普通平直钢纤维的材料相比,掺废轮胎钢丝水泥基材料的电磁屏蔽效能提高51%,且具有良好的导电性能与力学性能；适当增加废轮胎钢丝长度,可提高水泥基材料的电磁屏蔽性能与导电性能,但长度过长不利于钢丝在材料中的分散和材料制备；基体对材料电磁屏蔽性能具有一定影响,掺废轮胎钢丝水泥净浆试样与砂浆试样在频率低于1400 MHz时的屏蔽效能相近,但高于1400 MHz时水泥净浆的屏蔽效能要远好于水泥砂浆试样；试样厚度与屏蔽效能成正比关系,厚度为8mm的试样屏蔽效能比厚度为4 mm的试样屏蔽效能提高92%；养护龄期对材料导电性能的影响主要在早期,养护21 d后,材料电阻率基本趋于稳定；与单掺导电介质相比,复掺废轮胎钢丝与石墨、超导电炭黑等介质,可使材料导电性能及电磁屏蔽性能显著改善,复掺钢丝与炭黑的试样在30kHz—1500 MHz频率范围内的屏蔽效能最大可达29 dB。更多还原

【Abstract】 The electromagnetic shielding materials used in the buildings become a new content of modern architecture design. Cement-based electromagnetic shielding materials have some advantages such as low cost, convenient construction and large protection area, so its market prospect will be very bright in future.The effect of the waste tire steel wire as conductive agent added into the cement paste on the mechanical properties, electrical properties and electromagnetic shielding properties of materials are mainly studied in the paper. The preparation process and work properties of the materials are also researched. The electromagnetic shielding properties of materials made under the different conditions are investigated by taking the coaxial planarspectrum analyzer method, the conditions contain the volume fraction of the waste tire steel wire, curing age, curing condition, adding steel wire and graphite (superconductivity carbon black) and so on, and the conductivity of materials are tested by the four-probe method.The results show that the shielding properties and conductivity of the waste tire steel wire cement-based materials are better than those of the same volume fraction common straight steel fiber cement-based materials. Compared with the steel fiber cement-based materials, the electromagnetic shielding effectiveness of the waste tire steel wire cement-based materials are improved by 51%, which have good conducti-vity and mechanical properties. Increasing the length of the waste tire steel wire properly can improve the electromagnetic shielding properties and conductivity of the cement-based materials, but the dispersion of steel wire in the materials and materials preparation are difficult if the steel wire is too long. The matrix has certain influence on electromagnetic shielding effectiveness of the materials, and the shielding effectiveness of the tire steel wire cement-based paste sample is close to that of the mortar sample when the frequency is lower than 1400 MHz, but compared with the mortar sample the shielding effectiveness of the cement paste sample is obviously improved if the frequency is above 1400 MHz. The shielding effectiveness of the sample is proportional to its thickness. Compared with the 4 mm sample, the shielding effectiveness of the 8 mm sample is improved by 92%. The effect of curing age on electrical conductivity of the materials occur in early periods, and the resistivity of the materials are tended to be stable 21 days later. Compared with the materials added by single conducting medium, the conductivity and electromagnetic shielding properties of the materials are significantly improved when the waste tire steel wire and graphite, steel wire and superconductivity carbon black or steel wire and other medium are added together. The material added by the steel wire and carbon black reaches the maximum shielding effectiveness of 29 dB in the frequency range of 30 kHz—1500 MHz.更多还原