Kalina Lukáš, Bílek Vlastimil, Sedlačík Martin, Cába Vladislav, Smilek Jiří, Švec Jiří, Bartoníčková Eva, Rovnaník Pavel, Fládr Josef
Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech Republic.
Faculty of Civil Engineering, Brno University of Technology, 612 00 Brno, Czech Republic.
Materials (Basel). 2023 Mar 8;16(6):2173. doi: 10.3390/ma16062173.
Protection of concrete against aggressive influences from the surrounding environment becomes an important step to increase its durability. Today, alkali silicate solutions are advantageously used as pore-blocking treatments that increase the hardness and impermeability of the concrete's surface layer. Among these chemical substances, known as concrete densifiers, lithium silicate solutions are growing in popularity. In the present study, the chemical composition of the lithium silicate densifiers is put into context with the properties of the newly created insoluble inorganic gel responsible for the micro-filling effect. Fourier-transform infrared spectroscopy was used as a key method to describe the structure of the formed gel. In this context, the gelation process was studied through the evolution of viscoelastic properties over time using oscillatory measurements. It was found that the gelation process is fundamentally controlled by the molar ratio of SiO and LiO in the densifier. The low SiO to LiO ratio promotes the gelling process, resulting in a rapidly formed gel structure that affects macro characteristics, such as water permeability, directly related to the durability of treated concretes.
保护混凝土免受周围环境的侵蚀性影响成为提高其耐久性的重要一步。如今，碱金属硅酸盐溶液作为一种孔隙封堵处理剂被广泛应用，它能提高混凝土表层的硬度和抗渗性。在这些被称为混凝土致密剂的化学物质中，硅酸锂溶液越来越受欢迎。在本研究中，将硅酸锂致密剂的化学成分与负责微填充效应的新生成的不溶性无机凝胶的性质联系起来。傅里叶变换红外光谱法被用作描述所形成凝胶结构的关键方法。在此背景下，通过使用振荡测量随时间监测粘弹性性能的变化来研究凝胶化过程。结果发现，凝胶化过程从根本上受致密剂中SiO与LiO的摩尔比控制。低SiO/LiO比促进凝胶化过程，导致快速形成凝胶结构，这直接影响与处理后混凝土耐久性相关的宏观特性，如水渗透性。
