几种有机硅材料在南京城砖防护上的应用研究

南京将建成首家六朝博物馆,因此需要原址保护当时的城墙遗址.为隔断地下水,采取了帷幕注浆等止水措施.由于长期浸泡于水中加剧了城墙表面风化现象,因此为验证化学材料保护城砖的可能性,首先取样进行实验室研究,其中选择了氟硅类(S130)、聚硅氧烷类(派力克)和短链烷基硅氧烷类(甲基三甲氧基硅烷)三种有机硅材料作为城墙保护试验对象.试验项目包括对比样品整体浸泡渗透前后外观状态、接触角、吸水、透气性能、耐久性能的变化以及样品局部浸泡渗透前后外观状态与质量的变化.结果表明,经派力克和甲基三甲氧基硅烷保护后的样品各项性能相对较好,而亲水/憎水界面对试块影响程度与试块自身特性有关.这两种材料可尝试作为城墙的化学防风化保护材料,但还必须经过现场试验进行验证.

Application of organic silicone materials on the city wall of Nanjing

The first museum to exhibits Six Dynasties relics will be built in Nanjing, so the ruin of City Wall of that period needs on-site conservation. Curtain grouting was adopted to block groundwater. Because the wall has been immersed in water for a long time, the effloresce of wall's surfaces has accelerated. Organic silicone materials such as fluorinesilicone (S130), polysiloxane (pelicoat) and shortchain siloxane (methyltrimethoxysilicane) were tested to see if they are suitable conservation materials. These silicone materials were first applied on the samples in the laboratory. Results are evaluated based on appearance changes, contact angle, water absorption, water permeability,durability in complete immersion tests, appearance and quality changes in partially immersed tests. The results show that specimens after pelicoat and methyltrimethoxysilicane treatment are relatively good. Meanwhile, the hydrophilic nature of bricks and the waterresistance of organic conservation films have an effect on the test samples depending on the physical and chemical properties of the test samples. These two organic silicones may be useful as chemical conservation materials for treating the city wall. However, their applicability should be judged only after onsite experiments.