高韧性高阻尼的新型水泥基复合材料研发

发布时间：2018-01-31 05:27

本文关键词： PVA-ECC 硅烷偶联剂表面活性剂高韧性高阻尼　出处：《南京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：超高韧性水泥基复合材料(PVA-ECC)是近年来发明的一种新型的、优秀的纤维增强水泥基复合材料。它超强的韧性、独特的多缝开裂特性、应变硬化特性、丰富的产品种类以及突出的绿色环保性,不但可以显著改善混凝土结构的抗震性能和抗弯性能,实现建筑结构的自身耗能,而且具有很好的可持续发展意义。本文介绍了PVA-ECC的制备工艺,并从纤维掺量、水胶比、硅烷偶联剂、纤维长径比对PVA-ECC的影响出发,对其力学性能以及阻尼性能进行了研究,具体内容如下：(1)通过阅读文献,确定PVA-ECC的初始配合比,通过纤维分散情况、力学性能以及阻尼性能的反复试验,不断调整配合比,研发出一种高韧性高阻尼的新型复合水泥基材料。(2)本文为了改善纤维在水泥基体中分散情况,在基体中加入了表面活性剂,试验结果表明：加入表面活性剂有助于改善纤维在基体中的分散情况。(3)本文对PVA-ECC进行了小梁的四点弯曲试验,探究了其弯曲变形的能力。试验结果表明：在基体中掺入PVA纤维可以明显提高材料的强度和韧性,且PVA纤维掺量越高提高效果越好；提高水胶比可以增大材料的韧性但是会降低其强度；将纤维表面用硅烷偶联剂处理后可以增大材料的韧性和强度；纤维长度对PVA-ECC的韧性也有一定的影响,长纤维效果更优。(4)本文对PVA-ECC进行了轴向拉伸试验,研究表明：增大纤维掺量、提高水胶比、添加硅烷偶联剂以及增大纤维长径比均可以增大材料的延性,最大拉伸应变达到2.8%；PVA-ECC的拉伸弹性模量低于纯基体混凝土,说明它刚度变小韧性变大,通过其变形来释放更多能量；在拉伸过程中出现了应变硬化和多缝开裂两大特征。(5)本文对PVA-ECC进行了阻尼比试验,并总结了几种主要的耗能途径。试验结果表明：增大纤维掺量、提高水胶比、添加硅烷偶联剂、纤维长径比均可以提高材料的阻尼性能,最大阻尼比可达到7.5%。
[Abstract]:Ultrahigh toughness cement matrix composites PVA-ECCs are a new and excellent fiber reinforced cement matrix composites developed in recent years. Strain hardening characteristics, rich product types and outstanding green environmental protection can not only significantly improve the seismic and flexural properties of concrete structures, but also achieve the energy consumption of building structures. In this paper, the preparation process of PVA-ECC is introduced, and the effects of fiber content, water / binder ratio, silane coupling agent and fiber aspect ratio on PVA-ECC are introduced. The mechanical properties and damping properties of PVA-ECC are studied. The main contents are as follows: 1) by reading the literature, the initial blending ratio and fiber dispersion of PVA-ECC are determined. In order to improve the dispersion of fiber in cement matrix, a new composite cement-based material with high toughness and high damping has been developed through repeated tests of mechanical properties and damping properties. The experimental results show that the addition of surfactant helps to improve the dispersion of fibers in the matrix.) in this paper, the four-point bending test of PVA-ECC trabeculae was carried out. The results show that the strength and toughness of the material can be improved obviously by adding PVA fiber into the matrix, and the higher the content of PVA fiber is, the better the effect is. Increasing the water-binder ratio can increase the toughness of the material but reduce its strength. After the fiber surface was treated with silane coupling agent, the toughness and strength of the material could be increased. Fiber length also has a certain effect on the toughness of PVA-ECC. The effect of long fiber is better. 4) in this paper, the axial tensile test of PVA-ECC is carried out. The results show that: increase the content of fiber. The ductility of the material can be increased by increasing the water-binder ratio, adding silane coupling agent and increasing the fiber aspect ratio, and the maximum tensile strain reaches 2.8%. The tensile elastic modulus of PVA-ECC is lower than that of pure matrix concrete, which indicates that its stiffness becomes smaller and its toughness becomes larger, which releases more energy through its deformation. Strain hardening and multi-crack cracking appeared in the tensile process.) the damping ratio test of PVA-ECC was carried out in this paper. The experimental results show that increasing the fiber content, increasing the water / binder ratio, adding silane coupling agent and fiber aspect ratio can improve the damping property of the material. The maximum damping ratio can reach 7.5.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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