掺纳米石墨烯片水泥基复合材料的机敏性研究
发布时间：2019-05-10 19:19
【摘要】：水泥基智能复合材料将为混凝土结构的智能化提供重要支撑。石墨烯及其智能复合材料是近年来国内外研究的热点,但关于石墨烯在水泥基智能复合材料中的应用研究还很少见。而且,现有的水泥基智能复合材料延性较差,使其对拉伸应变的自感知范围远小于压应变的感知范围。因此,本文将最新的碳基纳米材料—纳米石墨烯片(GnPs)引入到水泥砂浆和高延性应变硬化水泥基智能复合材料(SHCC)中,比较这两类水泥基智能复合材料机敏性的差异,以此为结构健康监测提供新的水泥基智能复合材料。本文的主要工作如下:1、为利于GnPs在水中的均匀分散,确定了分散剂使用方法和超声振动分散工艺,由此制定了GnPs-水泥砂浆的配制工艺,使GnPs在水泥砂浆中达到较好的分散效果。研究结果表明,GnPs的分散效果会在很大程度上影响其对水泥砂浆的增强作用。2、GnPs-水泥砂浆抗压强度总体上随GnPs掺量增加而降低,但掺M5型号的GnPs使得GnPs-水泥砂浆抗压强度都比素水泥砂浆抗压强度高,呈现较好的增强效果。在改善导电性的效果上,掺M5型号的GnPs要比同样掺量的M25型号的GnPs效果更好,渗流阈值为GnPs体积掺量为1.0%左右。GnPs-水泥砂浆压敏灵敏度随掺量增加呈现开始增加而后减小的趋势,且灵敏度均在22以下。3、GnPs-SHCC具有较好的抗拉、抗压力学性能,GnPs的掺入提高了SHCC的极限拉伸强度和极限拉伸应变。GnPs-SHCC在循环拉伸时电阻变化率对拉伸应变有较高的敏感性,通过电阻变化率基线的下降可以感知SHCC在拉伸时产生的损伤。在循环压缩时,灵敏度远高于GnPs-水泥砂浆。随着GnPs掺量的增加,电阻率变化曲线的重复性有所提高,故GnPs-SHCC比GnPs-水泥砂浆具有更好的压敏性。4、在受压全过程中GnPs-SHCC的电阻都随应变增加而减小,说明GnPs-SHCC具有很宽的应变感知范围,即在0.25%左右,但GnPs-SHCC的灵敏度随应变水平增加有所降低。
[Abstract]:Cement-based intelligent composites will provide important support for the intelligence of concrete structures. Graphene and its intelligent composites are the focus of research at home and abroad in recent years, but the application of graphene in cement-based intelligent composites is still rare. Moreover, the ductility of the existing cement-based intelligent composites is poor, which makes the self-sensing range of tensile strain much smaller than the sensing range of compressive strain. Therefore, in this paper, the latest carbon-based nanomaterials, nano-graphene sheet (GnPs), are introduced into cement mortar and high ductile strain-hardening cement-based intelligent composites (SHCC), and the differences in the sensitivity of the two kinds of cement-based intelligent composites are compared. This provides a new cement-based intelligent composite for structural health monitoring. The main work of this paper is as follows: 1. In order to facilitate the uniform dispersion of GnPs in water, the use method of dispersant and ultrasonic vibration dispersion technology were determined, and the preparation process of GnPs- cement mortar was established. So that GnPs in cement mortar to achieve a better dispersion effect. The results show that the dispersion effect of GnPs will affect the reinforcement of cement mortar to a great extent. (2) the compressive strength of GnPs-cement mortar decreases with the increase of GnPs content. However, the compressive strength of GnPs- cement mortar is higher than that of plain cement mortar due to the addition of M5 type of GnPs. In terms of improving electrical conductivity, the M5-doped GnPs is better than the M25 GnPs in the same amount. The seepage threshold is about 1.0% of GnPs volume content. The varistor sensitivity of GnPs-cement mortar begins to increase and then decreases with the increase of admixture, and the sensitivity is below 22. 3, GGPs 鈮，
本文编号：2473931
[Abstract]:Cement-based intelligent composites will provide important support for the intelligence of concrete structures. Graphene and its intelligent composites are the focus of research at home and abroad in recent years, but the application of graphene in cement-based intelligent composites is still rare. Moreover, the ductility of the existing cement-based intelligent composites is poor, which makes the self-sensing range of tensile strain much smaller than the sensing range of compressive strain. Therefore, in this paper, the latest carbon-based nanomaterials, nano-graphene sheet (GnPs), are introduced into cement mortar and high ductile strain-hardening cement-based intelligent composites (SHCC), and the differences in the sensitivity of the two kinds of cement-based intelligent composites are compared. This provides a new cement-based intelligent composite for structural health monitoring. The main work of this paper is as follows: 1. In order to facilitate the uniform dispersion of GnPs in water, the use method of dispersant and ultrasonic vibration dispersion technology were determined, and the preparation process of GnPs- cement mortar was established. So that GnPs in cement mortar to achieve a better dispersion effect. The results show that the dispersion effect of GnPs will affect the reinforcement of cement mortar to a great extent. (2) the compressive strength of GnPs-cement mortar decreases with the increase of GnPs content. However, the compressive strength of GnPs- cement mortar is higher than that of plain cement mortar due to the addition of M5 type of GnPs. In terms of improving electrical conductivity, the M5-doped GnPs is better than the M25 GnPs in the same amount. The seepage threshold is about 1.0% of GnPs volume content. The varistor sensitivity of GnPs-cement mortar begins to increase and then decreases with the increase of admixture, and the sensitivity is below 22. 3, GGPs 鈮，
本文编号：2473931
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