【摘要】：水泥基智能復(fù)合材料將為混凝土結(jié)構(gòu)的智能化提供重要支撐。石墨烯及其智能復(fù)合材料是近年來國內(nèi)外研究的熱點,但關(guān)于石墨烯在水泥基智能復(fù)合材料中的應(yīng)用研究還很少見。而且,現(xiàn)有的水泥基智能復(fù)合材料延性較差,使其對拉伸應(yīng)變的自感知范圍遠(yuǎn)小于壓應(yīng)變的感知范圍。因此,本文將最新的碳基納米材料—納米石墨烯片(GnPs)引入到水泥砂漿和高延性應(yīng)變硬化水泥基智能復(fù)合材料(SHCC)中,比較這兩類水泥基智能復(fù)合材料機(jī)敏性的差異,以此為結(jié)構(gòu)健康監(jiān)測提供新的水泥基智能復(fù)合材料。本文的主要工作如下:1、為利于GnPs在水中的均勻分散,確定了分散劑使用方法和超聲振動分散工藝,由此制定了GnPs-水泥砂漿的配制工藝,使GnPs在水泥砂漿中達(dá)到較好的分散效果。研究結(jié)果表明,GnPs的分散效果會在很大程度上影響其對水泥砂漿的增強作用。2、GnPs-水泥砂漿抗壓強度總體上隨GnPs摻量增加而降低,但摻M5型號的GnPs使得GnPs-水泥砂漿抗壓強度都比素水泥砂漿抗壓強度高,呈現(xiàn)較好的增強效果。在改善導(dǎo)電性的效果上,摻M5型號的GnPs要比同樣摻量的M25型號的GnPs效果更好,滲流閾值為GnPs體積摻量為1.0%左右。GnPs-水泥砂漿壓敏靈敏度隨摻量增加呈現(xiàn)開始增加而后減小的趨勢,且靈敏度均在22以下。3、GnPs-SHCC具有較好的抗拉、抗壓力學(xué)性能,GnPs的摻入提高了SHCC的極限拉伸強度和極限拉伸應(yīng)變。GnPs-SHCC在循環(huán)拉伸時電阻變化率對拉伸應(yīng)變有較高的敏感性,通過電阻變化率基線的下降可以感知SHCC在拉伸時產(chǎn)生的損傷。在循環(huán)壓縮時,靈敏度遠(yuǎn)高于GnPs-水泥砂漿。隨著GnPs摻量的增加,電阻率變化曲線的重復(fù)性有所提高,故GnPs-SHCC比GnPs-水泥砂漿具有更好的壓敏性。4、在受壓全過程中GnPs-SHCC的電阻都隨應(yīng)變增加而減小,說明GnPs-SHCC具有很寬的應(yīng)變感知范圍,即在0.25%左右,但GnPs-SHCC的靈敏度隨應(yīng)變水平增加有所降低。
[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，

本文編號：2473931