Ban Matea, De Kock Tim, Ott Frédéric, Barone Germana, Rohatsch Andreas, Raneri Simona
Institute of Geotechnics, Research Centre of Engineering Geology, Vienna University of Technology, 1040 Vienna, Austria.
Department of Geology, Ghent University, 9000 Ghent, Belgium.
Nanomaterials (Basel). 2019 Apr 19;9(4):635. doi: 10.3390/nano9040635.
A nano-silica consolidant and nano-titania modified tetraethyl-orthosilicate were applied on two building stones, a carbonate and a silicate, by brush, poultice or capillary absorption. Neutron radiography was used to monitor capillary water absorption, and to analyse changes in physical properties caused by heat treatment of specimens for the purposes of artificially ageing and different treatment applications with stone consolidants. Moreover, ultrasonic pulse velocity and gravimetrically determined water absorption were analysed to cross-validate neutron radiography. The results reveal that reactive systems like tetraethyl-orthosilicates need an unknown period for polymerisation, which makes nano-silica consolidants more favourable for construction follow-up work. While polymerisation is incomplete, hydrophobic behaviour, water trapping and pore clogging are evident. Within the tetraethyl-orthosilicate treatment, poultice and brushing are strongly influenced by the applicant, which results in wide ranging amounts of water absorbed and anomalous water distributions and kinetics. The carbonate lithotype displays polymerisation initiated in the core of the specimen, while the lateral surfaces are still mostly hydrophobic. Reaction time differences can be attributed to the different amounts of consolidants applied, which is a result of the chosen application settings. Artificial ageing of stone specimens is a prerequisite when mechanical strength gain is studied, as demonstrated by sound speed propagation.
通过刷涂、膏剂或毛细吸收的方式，将纳米二氧化硅加固剂和纳米二氧化钛改性原硅酸四乙酯应用于一块碳酸盐石材和一块硅酸盐石材这两种建筑石材上。利用中子射线照相术监测毛细吸水率，并分析对样品进行热处理以实现人工老化和使用石材加固剂进行不同处理应用所引起的物理性能变化。此外，还对超声脉冲速度和重量法测定的吸水率进行了分析，以交叉验证中子射线照相术的结果。结果表明，像原硅酸四乙酯这样的反应体系需要一段未知的聚合时间，这使得纳米二氧化硅加固剂更有利于施工后续工作。在聚合不完全的情况下，疏水行为、水分截留和孔隙堵塞现象明显。在原硅酸四乙酯处理过程中，膏剂和刷涂受施工人员的影响很大，这导致吸水率范围广泛且水分分布和动力学异常。碳酸盐岩类型在样品核心处引发聚合反应，而侧面大多仍保持疏水状态。反应时间差异可归因于所施加加固剂的量不同，这是所选施工设置的结果。如声速传播所示，在研究机械强度增加时，石材样品的人工老化是一个先决条件。
