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试验探讨了聚乙烯醇(PVA)及其掺量对纳米碳黑-水泥砂浆力学性能的影响,结果表明:当PVA掺量为0.2%时,改性水泥砂浆的抗压、抗折强度和黏结弯曲强度分别提高了32.1%,12.2%和18.6%.采用扫描电镜、傅里叶红外光谱、X射线衍射光谱和差示扫描热分析仪观察了PVA改性纳米碳黑-水泥砂浆的物理化学性能,结果表明:当PVA掺量较少时,PVA形成丝状聚合物膜均匀分散于水泥砂浆中,填充孔洞和桥接裂缝,改善了水泥砂浆的微细观结构;但是,当PVA掺量过多时会在水泥浆体内形成大量片状结构,包裹水泥颗粒和水泥水化产物,阻碍水泥的水化速度,导致改性砂浆的力学强度降低.
The effects of polyvinyl alcohol (PVA) and its content on the mechanical properties of nano-carbon black-cement mortar were investigated. The results showed that the compressive strength, flexural strength and adhesion of the modified cement mortar when the content of PVA was 0.2% Flexural strength increased by 32.1%, 12.2% and 18.6% respectively.The physicochemical properties of PVA-modified nano-carbon black-cement mortar were observed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and differential scanning calorimetry The results showed that when the content of PVA was small, PVA formed filamentary polymer membrane dispersed uniformly in cement mortar, filling holes and bridging cracks, improving the microstructure of cement mortar; however, when PVA content was too much The formation of a large number of sheets in the cement slurry structure, wrapped cement particles and cement hydration products, hinder the hydration rate of cement, resulting in reduced mechanical strength of modified mortar.