Abstract Efflorescence is widely regarded as a serious problem in cement-based exterior wall. This phenomenon can affect the appearance and long-term stability of the building. Based on the efflorescence mechanism, one of the causes of efflorescence is the existence of free water to dissolve soluble salts. Therefore, we propose a method for synthesizing hydrophobic cement mortar. The main challenge of the super-hydrophobic coating is its robust durability. To synthesize durable hydrophobic cement mortar, we use PVA as an adhesive to enhance the durability of the coating, and use siloxane material as a hydrophobic agent, through high-speed mixing, to obtain a PVA-coated siloxane material hydrophobic coating. Optical microscope and scanning electron microscope (SEM) and FT-IR spectroscopy were utilized to characterize the emulsions and coatings. Appearance analysis of the coatings was performed using a colorimeter and UV Spectrophotometer, and the durability of the coating was evaluated by abrasion resistance and water resistance. The measured water contact angles (CA) are between 120° to 140°, and the water absorption after 24 h and 48 h can be reduced by about 10 % and 15 % compared with the reference sample, including the water absorption coefficient is approximately lower than the untreated group 1.7–4 times. Finally, accelerated efflorescence test, image acquisition and analysis with Matlab software, determination of calcium ion leaching rate and TG-DSC analysis were performed. The results show that the cement mortar treated with hydrophobic emulsion has excellent water resistance and improved efflorescence resistance, and can be widely used in cement-based buildings.

中文翻译：

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疏水水泥砂浆PVA-硅氧烷混合乳液涂料的研究

摘要 白化是水泥基外墙的一个严重问题。这种现象会影响建筑物的外观和长期稳定性。根据风化机理，风化的原因之一是存在溶解可溶性盐的游离水。因此，我们提出了一种合成疏水水泥砂浆的方法。超疏水涂层的主要挑战是其强大的耐用性。合成耐用疏水水泥砂浆，我们以PVA为粘合剂，增强涂层的耐久性，以硅氧烷材料为疏水剂，通过高速混合，得到PVA包覆硅氧烷材料的疏水涂层。利用光学显微镜和扫描电子显微镜 (SEM) 以及 FT-IR 光谱来表征乳液和涂层。使用色度计和紫外分光光度计对涂层进行外观分析，并通过耐磨性和耐水性来评估涂层的耐久性。测得的水接触角（CA）在120°至140°之间，24小时和48小时后的吸水率与参考样品相比可降低约10%和15%，其中吸水系数约更低比未治疗组高 1.7-4 倍。最后进行了加速风化试验、图像采集与Matlab软件分析、钙离子浸出率测定和TG-DSC分析。结果表明，经疏水乳液处理的水泥砂浆具有优异的耐水性和抗风化性能，可广泛应用于水泥基建筑。