Kurpińska Marzena, Karwacki Jarosław, Maurin Artur, Kin Marek
Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Narutowicza 11/12 st., 80-233 Gdansk, Poland.
Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Heat Transfer Department, Fiszera 14 st., 80-231 Gdańsk, Poland.
Materials (Basel). 2021 Mar 11;14(6):1351. doi: 10.3390/ma14061351.
The implementation of low-energy construction includes aspects related to technological and material research regarding thermal insulation. New solutions are sought, firstly, to reduce heat losses and, secondly, to improve the environment conditions in isolated rooms. The effective heat resistance of insulating materials is inversely proportional to temperature and humidity. Cement composites filled with lightweight artificial aggregates may be a suitable material. Selecting a proper method for measuring the thermal conductivity of concrete is important to achieve accurate values for calculating the energy consumption of buildings. The steady state and transient methods are considered the two main thermal conductivity measurement approaches. Steady state is a constant heat transfer, whereby the temperature or heat flow is time independent. In the transient method, temperature changes over time. Most researchers have measured the conductivity of cement-based materials based on transient methods. The availability and cost of equipment, time for experimental measurements and measurement ability for moist specimens may be some of the reasons for using this method. However, considering the accuracy of the measurements, the steady state methods are more reliable, especially for testing dry materials. Four types of composites were investigated that differed in filler: natural aggregate, sintered fly ash filler, sintered clay and granular foam glass aggregate. The method of preparing the samples for testing is especially important for the obtained results. The samples, with a specific surface roughness, will show a lower coefficient of thermal conductivity by 20-30%; therefore, the selection of the type of contact layer between the plate of the measuring device and the sample is of particular importance.
低能耗建筑的实施包括与隔热技术和材料研究相关的方面。首先要寻求新的解决方案来减少热损失，其次要改善隔离房间内的环境条件。隔热材料的有效热阻与温度和湿度成反比。填充轻质人工骨料的水泥复合材料可能是一种合适的材料。选择合适的混凝土导热系数测量方法对于获得准确的建筑能耗计算值很重要。稳态法和瞬态法被认为是两种主要的导热系数测量方法。稳态是一种恒定的热传递，即温度或热流与时间无关。在瞬态法中，温度随时间变化。大多数研究人员基于瞬态法测量水泥基材料的导热系数。设备的可用性和成本、实验测量时间以及对潮湿试样的测量能力可能是使用这种方法的一些原因。然而，考虑到测量的准确性，稳态法更可靠，特别是对于测试干燥材料。研究了四种不同填料的复合材料：天然骨料、烧结粉煤灰填料、烧结粘土和粒状泡沫玻璃骨料。制备测试样品的方法对于获得的结果尤为重要。具有特定表面粗糙度的样品的导热系数将降低20 - 30%；因此，测量装置平板与样品之间接触层类型的选择尤为重要。
