Průša David, Šťastník Stanislav, Svobodová Kateřina, Šuhajda Karel, Sochorová Zuzana
Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1665/1, 613 00 Brno, Czech Republic.
Institute of Building Structures, Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00 Brno, Czech Republic.
Gels. 2024 Aug 22;10(8):543. doi: 10.3390/gels10080543.
The present work analyzes the effect of releasing physically bound water from hydrogel, cork, perlite, and ceramsite on materials exposed to microwave radiation and subsequently investigates possible changes in the physical properties of these materials (water absorption and thermal conductivity coefficient). The release of physically bound water from individual materials has potential practical applications in materials engineering, for example, in the internal curing of concrete, where individual aggregates could, under the influence of microwave radiation, release water into the structure of the concrete and thus further cure it. Experimental analysis was carried out with samples of the above-mentioned materials, which were first weighed and then immersed in water for 24 h. Then, they were weighed again and exposed to microwave radiation. After exposure, the samples were weighed again, left immersed in water for 24 h, and weighed again. The focus of the study was on the ability of the aggregates to release water due to microwave radiation and on the changes in the properties (water absorption, thermal conductivity coefficient) of these materials when exposed to microwave radiation. The samples were further monitored by digital microscopy for possible changes in the surface layer of the materials. The hydrogels show the highest water absorption (1000%) and the fastest water release (45 min to complete desiccation). After the release of water due to microwave radiation, their ability to absorb water is maintained. Of interest, however, is that in the case of almost complete removal of water from the soaked hydrogel, the original powdered state of the hydrogel is not obtained, but the outcome has rather a solid structure. In the case of cork, the water absorption depends on the fraction of the material.
本研究分析了从水凝胶、软木、珍珠岩和陶粒中释放物理结合水对暴露于微波辐射的材料的影响，并随后研究了这些材料物理性质（吸水率和导热系数）可能发生的变化。从单个材料中释放物理结合水在材料工程中具有潜在的实际应用，例如在混凝土的内部养护中，在微波辐射的影响下，单个集料可以将水释放到混凝土结构中，从而进一步养护混凝土。对上述材料的样品进行了实验分析，首先对样品称重，然后将其浸泡在水中24小时。然后，再次称重并使其暴露于微波辐射。暴露后，再次对样品称重，使其再次浸泡在水中24小时，然后再次称重。该研究的重点是集料因微波辐射而释放水的能力，以及这些材料在暴露于微波辐射时其性质（吸水率、导热系数）的变化。通过数字显微镜对样品进行进一步监测，以观察材料表层可能发生的变化。水凝胶显示出最高的吸水率（1000%）和最快的水分释放速度（45分钟完全干燥）。由于微波辐射导致水释放后，它们保持了吸水能力。然而，有趣的是，在几乎完全去除浸泡水凝胶中的水的情况下，并未得到水凝胶原来的粉末状态，而是得到了具有相当坚固结构的产物。对于软木，吸水率取决于材料的粒度。
