原位纳米SiO2防护剂防水效果试验

Experimental Study on Waterproofing Effect of In-situ Nano-SiO2 Protective Agent

我国北方地区冬季路面养护时大量使用融雪剂,由于路面表层抗渗透性能不足,路面结构耐久性会被破坏。按不同成分比例将正硅酸乙酯(TEOS)、乙醇和水配制成防护液,将其涂刷于试件表面,分析吸水率与防护液配合比的关系,并研究喷涂量、喷涂遍数对试件吸水率的影响,同时结合微观结构进行分析讨论,进一步揭示防护剂的作用机理。研究结果表明:各配合比防护液均能降低试件吸水率,降低率最高可达70%;相比于喷涂量,喷涂遍数对试件吸水率的影响更明显;喷涂完成后密封试件表面6h,试件吸水率降低比例最高。通过电子显微镜扫描以及能谱分析发现,防护剂可以在一定厚度范围内生成硅酸钙胶凝,加强表层结构密实度,有效提高混凝土结构的抗渗性能。

In northern China, snow-melting agent is widely used in winter maintenance of highway. The impermeability of pavement surface is insufficient, which leads to durability damage of pavement structure. In this experiment, protective fluids made of tetraethyl orthosilicate(TEOS), ethanol and water with different mix ratios were applied on the surface of mortar specimens. The relationship between water absorption and the mix ratio of protective fluids was analyzed. The effects of spraying amount and times on water absorption of mortar were studied. At the same time, the mechanism of protective fluids was further revealed by analyzing and discussing the microstructure. The results show that the water absorption of mortar decreases with each proportioning of protective fluid, up to 70%. Compared with the amount of each spraying, the effect of spraying times on the water absorption of mortar is more obvious. After spraying, the water absorption decreases most when the surface of the specimen is sealed for 6 hours. Scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) analysis show that the protective agent can produce cementitious substances and compact structure in a certain thickness range, which can effectively improve the permeability of mortar.