Kaczmarek Anna, Wesołowska Maria
Faculty of Civil and Environmental Engineering and Architecture, Bydgoszcz University of Science and Technology, 85-796 Bydgoszcz, Poland.
Materials (Basel). 2022 Aug 17;15(16):5653. doi: 10.3390/ma15165653.
This paper takes into consideration the performance of traditional bricks as part of a building exterior wall finish. Exterior wall materials change their properties when exposed to external environment. This process is extended over time and its intensity is closely related to microstructure, moisture and freeze-thaw cycles. Two methods of freeze-thaw durability tests were used in this study: standard and defined by the authors. The authors' method incorporated the actual conditions of masonry unit function in exterior wall finish, i.e., cyclical effects of precipitation water, changes in temperature and air humidity. The laboratory test study included 50 freeze-thaw cycles. Three characteristic ranges of pore dimensions were indicated in the analysis: below 0.1 µm, between 0.1 and 3.0 µm and above 3 µm. Based on the method of freeze-thaw durability testing, the areas of microstructure changes were determined. The obtained results were related to the absorption of ceramic building materials. The authors' method confirms the usage of traditional ceramic building materials designed for use in protected walls against water penetration in unprotected exterior wall finish. The critical water saturation method of masonry units (standard) based on extreme environmental conditions generates significant changes in porosity distribution that do not reflect real, i.e., moderate, conditions. This method is appropriate for masonry units operating in severe conditions, i.e., F2. The aim of this study is to suggest a methodology for durability tests of traditional ceramic masonry units to cyclic freezing and thawing, which are only exposed to F1 (moderate) conditions during operation. Changes in the microstructure of the ceramic building materials were used as the primary evaluation criterion. In order to determine the effect of cyclic temperature changes, the freeze-thaw durability test was performed according to generally accepted standard procedures and in-house methodology. The purpose of the study is to point out the individual approach for the analysis of the material-environment system. At the same time, it should inspire researchers to innovative methods which use external conditions in a laboratory environment.
本文考虑了传统砖作为建筑外墙饰面一部分的性能。外墙材料在暴露于外部环境时会改变其性能。这个过程会随着时间延长，其强度与微观结构、水分和冻融循环密切相关。本研究采用了两种冻融耐久性测试方法：标准方法和作者定义的方法。作者的方法纳入了砌体单元在外墙饰面中的实际使用条件，即降水、温度变化和空气湿度的循环影响。实验室测试研究包括50次冻融循环。分析中指出了三个特征孔隙尺寸范围：低于0.1微米、介于0.1和3.0微米之间以及高于3微米。基于冻融耐久性测试方法，确定了微观结构变化的区域。所得结果与陶瓷建筑材料的吸水率相关。作者的方法证实了设计用于保护墙体以防渗水的传统陶瓷建筑材料可用于无保护的外墙饰面。基于极端环境条件的砌体单元临界水饱和度方法（标准方法）会导致孔隙率分布发生显著变化，而这并不能反映实际的（即适度的）条件。这种方法适用于在恶劣条件下（即F2）运行的砌体单元。本研究的目的是提出一种针对传统陶瓷砌体单元进行循环冻融耐久性测试的方法，这些砌体单元在运行期间仅暴露于F1（适度）条件下。将陶瓷建筑材料微观结构的变化用作主要评估标准。为了确定循环温度变化的影响，按照普遍接受的标准程序和内部方法进行了冻融耐久性测试。该研究的目的是指出对材料 - 环境系统进行分析的独特方法。同时，它应激励研究人员采用在实验室环境中利用外部条件的创新方法。
