Influence of stone conservation actions on the long-term weathering behaviour of natural stones

天然石材的腐烂程度取决于矿物含量、粘结性能、孔隙条件以及应力类型和风化类型。通过使用保鲜剂，可以影响甚至减少石头的腐烂。本研究项目主要研究石材保存后随时间推移的腐烂情况。为了评估在自然风化条件下的石材保护行动的长期效果，德国伯格鲍姆博物馆为这项研究提案提供了一项关于25年前风化的天然石材的免费暴露研究。这些样品未经处理，并用防水剂处理，或者更确切地说，与石材增强剂结合使用。为分析保存石的腐烂过程和开发基于单边核磁共振技术的无损检测系统提供了独特的物质基础。石材随时间风化和活性物质通过非破坏性测试方法降解之间的深度相关性很少被研究。本研究项目旨在发展核磁共振技术，以验证石材保护剂的长期效果。这项提议的目的是建立一个经过科学验证的数据库的最终概念，以生成与时间相关的石块腐烂的风化模型。这一目标的主要数据基础包括自由暴露研究中分析的天然石块的测量结果。结果是由破坏性和非破坏性实验室调查确定的。这些值将被合并到一个地理信息系统辅助的数据库中，并在开放访问的网络-地理信息系统界面上可视化，以便未来的用户可以参考生成的知识状态。基于该数据库的预测模型将能够模拟天然石材随参数变化的风化潜力。该研究项目提供了无损检测方法的技术开发以及修复措施的长期结构化性能测试。

The decay of natural stone depends on the mineral content, the binding behaviour, the pore space conditions as well as the type of stress and type of weathering. By the use of preserving agents, stone decay can be influenced or even reduced. This research project focuses on the stone decay after stone conservation over time. To evaluate the long-term effect of a stone conservation action under natural weathering conditions, the Deutsche Bergbaumuseum provides for this research proposal about 25-year-old weathered natural stones of a free exposure study. These samples are untreated as well as treated with water repellent agents or rather in combination with stone strengthener. They provide a unique material basis to analyse the stone decay of conserved stones and to develop a non-destructive testing measuring system based on unilateral NMR-technique. The depth-dependent correlation between stone weathering over time and degradation of active substances by the use of non-destructive testing methods is rarely examined. This research project aims to develop the NMR-technique in order to validate the long-term effect of stone protective substances. Aim of this proposal is the final conception of a scientifically proven database to generate weathering models for time-dependent stone decay. The main data basis for this aim consists of the measurement results of the analysed natural stones of the free exposure study. The results were determined by destructive as well as non-destructive laboratory investigations. These values will be merged in a GIS-assisted database and visualised on a web-GIS interface with open-access, so that future users can refer to the generated state of knowledge. Forecast models based on this database will enable the simulation of the parameter-dependent weathering potential of natural stones. This research project provides a technological development of a non-destructive testing method as well as a long-term structured performance test for repair measures.