KH

摘要

两亲性硅烷偶联剂（SCA）改善橡胶与水化产物两相之间的弱键合，填充界面间隙，有效修复橡胶与水化产物之间的界面缺陷。PVA纤维的添加主要改善混凝土的抗裂性能和耐久性能。然而，大多数针对这一问题的研究仅限于现象学，忽略了原子结构层面的作用机制。因此，本研究从宏观力学性能、微细结构、化学成分和纳米光学水平的多尺度分析，探讨KH-560偶联剂增强PVA纤维-橡胶混凝土界面性能的增强机理。根据宏观力学测试的结果，结果发现，KH-560偶联剂可提高PVA-橡胶混凝土的抗压、抗折、抗剪强度，使损伤形态也由脆性损伤转变为塑性损伤，并且混凝土的抗压强度略有降低。 PVA的添加，却增强了耐久性和抗裂性。XRD（X射线衍射）、FT-IR（傅里叶变换红外光谱）和SEM（扫描电子显微镜）测试观察到一些凝胶和聚合物的存在填充了界面缝隙并有效修复了界面缺陷。通过纳米水平的分子动力学模拟两相界面，发现KH560分子可以通过Si-O-Si化学键与CSH凝胶集体紧密连接，和KH560分子键在CSH和橡胶界面之间分布不均匀，而改性剂KH560和PVA纤维的添加导致界面处有更多的氢键和离子键，从而增强了界面相互作用能。对SCA改性前后的PVA纤维橡胶土材料进行了宏观、微观、精细和纳米级多尺度分析的系统实验，最终实现了PVA橡胶水泥基SCA改性的设计和性能改进。多尺度框架中的材料。图形摘要如图 1 所示。对SCA改性前后的PVA纤维橡胶土材料进行了宏观、微观、精细和纳米级多尺度分析的系统实验，最终实现了PVA橡胶水泥基SCA改性的设计和性能改进。多尺度框架中的材料。图形摘要如图 1 所示。对SCA改性前后的PVA纤维橡胶土材料进行了宏观、微观、精细和纳米级多尺度分析的系统实验，最终实现了PVA橡胶水泥基SCA改性的设计和性能改进。多尺度框架中的材料。图形摘要如图 1 所示。

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ABSTRACT

Amphiphilic Silane coupling agent (SCA) improves the weak bond between the two phases of rubber and hydration products, fills the interfacial gaps and effectively repairs the interfacial defects between rubber and hydration products. The addition of PVA fibers mainly improves the cracking performance and durability of concrete. However, most of the studies addressing this issue have been limited to phenomenology, ignoring the mechanism of action at the atomic structure level. Therefore, this study investigates the strengthening mechanism of the interfacial properties of KH-560 coupling agent-reinforced PVA fiber-rubber concrete from the multi-scale analysis of macro-mechanical properties, micro and fine structure, chemical composition and nano-optical level. Based on the results of macro-mechanical tests, it was found that the KH-560 coupling agent could improve the compressive, flexural and shear strength of PVA-rubber concrete, so that the damage morphology also changed from brittle damage to plastic damage, and the compressive strength of concrete was slightly reduced due to the addition of PVA, but the durability and cracking resistance were enhanced. XRD (X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy) and SEM (scanning electron microscopy) tests observed the presence of some gels and polymers that filled the interfacial slits and effectively repaired the interfacial defects. The two-phase interface was simulated by molecular dynamics at the nano level, and it was found that KH560 molecules could be closely connected with C-S-H gel collectively through Si-O-Si chemical bonding, and KH560 molecular bonds were unevenly distributed between the C-S-H and rubber interfaces, while the addition of modifier KH560 and PVA fibers caused more hydrogen and ionic bonds at the interface, which enhanced the interfacial interaction energy. Systematic experiments were conducted on PVA fiber-rubber soil materials before and after SCA modification under macroscopic, microscopic, fine and nano-level multi-scale analyses, which ultimately lead to the design and performance improvement of SCA modification of PVA-rubber cement-based materials in a multi-scale framework. The graphic summary is shown in Figure 1.