【作者】 李健；

【导师】 唐祖全； 钱觉时；

【作者基本信息】 重庆大学 ， 材料学， 2005， 硕士

【摘要】 普通混凝土在长时间使用过程中,由于环境侵蚀、疲劳应力以及人为因素等作用,一些混凝土结构内部会出现严重损伤,有的甚至发生突然的脆性断裂,造成严重后果。因此,有必要进行有关重大土木基础设施的安全健康监测和自适应控制系统的探索与研究,预防重大事故发生。本文开展钢渣混凝土的导电性能与压敏性能研究将为混凝土结构的智能化提供了理论和实验基础,使混凝土结构集承载、感知、驱动等功能于一身。钢渣是炼钢过程中产生的废渣,由于钢渣中含有较高的金属铁及其氧化物,因此本论文选择钢渣作为导电相材料,以钢渣取代普通混凝土中的粗、细骨料以及掺和料来制备机敏混凝土。鉴于国内外对钢渣混凝土的压敏性能研究结果较少,本论文拟通过试验来研究钢渣混凝土的导电性和在受力时的压-阻特性,探讨其导电机理和电学性能随应力、应变的变化规律。本课题属于国家自然科学基金资助项目(50404005),本文在大量试验的基础上,分析了钢渣混凝土的导电机理;通过施加不同荷载,系统研究了钢渣混凝土电学性能随应力、应变的变化规律并对压敏性能影响因素进行了探讨。试验研究结果表明:⑴钢渣混凝土不但具有良好的力学性能,且具有较好的导电性,钢渣掺量越大,龄期和含水量等因素对电阻率影响越小;⑵钢渣混凝土的电阻率具有压力敏感性,其电阻率会随着压力的变化而增大或减小。因此,钢渣混凝土可以应用于混凝土结构的健康监测,预防严重事故的发生。⑶在施加荷载速度不同、长时间荷载,以及受弯荷载等情况下,钢渣混凝土的电阻率都会呈现一定的规律;⑷测试了钢渣混凝土试件在周边有约束时的压敏性,结果表明当钢渣混凝土四周受到约束时,其压敏性的灵敏度有所降低;⑸试验表明,当温度在零度以下时,钢渣混凝土出现正压力系数效应,即电阻随着压力的增大而增大,当温度在零度以上时,钢渣混凝土呈现负压力系数效应,即电阻随着压力的增大而减小。并且随着温度的升高,压力敏感性降低;⑹试验发现,龄期和强度等不同因素对钢渣混凝土压力敏感性都有一定程度的影响。更多还原

【Abstract】 Under long working time, serious damage, even sudden breakage of ordinary concrete has happened because of environment corrosion, man-made factors and fatigue stress. So it is necessary to develop a healthy monitoring and self-adaptive control system for concrete structure, especially, for some infrastructures. The study of electrical performance and strain sensing would serve theoretical and experimental foundation for the smart concrete which could be integrated with the performance of loading, sensing and transmission.Steel slag is an off scum in the course of steel making, steel slag includes high content of iron oxide, therefore, this thesis chooses steel slag as conductive material and makes it as coarse and fine aggregate substitute. While little findings of pressure sensitivity of steel slag concrete have been got yet, thus, the thesis studied the electrical conductive performance and pressure sensitivity of steel slag concrete systemically by test analysis and researched the conductive mechanism.The National Natural Science Foundation of China (50404005) supports the project. The thesis analyzed the conductive mechanism of steel slag concrete by test analysis; analyzed the conductivity of steel slag concrete developed with diverse stress and studied the affecting factor. The results revealed:⑴Steel slag concrete had good performance in conductivity and mechanics, the ages and moisture content have a little affect for resistivity of steel slag concrete with a large content of ground steel slag.⑵The result showed that steel slag concrete had good pressure sensitivity, theresistivity decreased or increased with press accretion. Therefore, strain sensing could be used for stress evaluation in concrete.⑶The change of the resistivity revealed some regulation under different loading rate and long time loading etc.⑷The compression sensibility of steel slag concrete is measured when the specimen is restrained around the periphery. The result shows that the pressure sensitivity reduces when the specimen is restrained around the periphery.更多还原