Long-term thermal productivity of polystyrene concrete in a new composite wall in a fixed formwork
Authors: Meneylyuk O. I , Bochevar K. I , O.L O. L 
Published: June 2023

Purpose. Determination of the term of long-term thermal productivity of expanded polystyrene concrete in a new composite frame wall in a fixed formwork. Methodology. Methods of analysis and synthesis were used to conduct a patent search and develop a research methodology. The search was conducted using the patent database of Ukrainian Institute of Scientific and Technical Expertise and Information. Experimental studies were carried out in accordance with State Standard of Ukraine B V.2.7-38-95. The essence of the experiment consisted in reproducing the natural conditions of the “freeze-thaw-heat” cycle and measuring the thermal insulation characteristics of the main insulating material – polystyrene concrete – before and after the tests. Based on this, a conclusion was made about the long-term thermal productivity of the expanded polystyrene concrete in a new composite wall in the fixed formwork. The calculation of the dependence of thermal productivity on the number of cycles was carried out by arithmetic means using standard methods and programs such as Microsoft Excel. Findings. New technical solution of a composite wall made of expanded polystyrene concrete in a fixed formwork using light steel thin-walled structures has been created. A methodology for researching the long-term thermal productivity of this composite wall has been developed. An experimental study was conducted to research the influence of cyclic temperature changes (“freeze-thaw-heat”) on the long-term thermal productivity of the main heat-insulating element of the composite wall – expanded polystyrene concrete. An appropriate analytical model of the dependence of long-term thermal productivity of expanded polystyrene concrete samples on the number of “freeze-thaw-heat” cycles was calculated. The possibility of effective operation of the structure was confirmed by checking the normative values of the resource index and the factor of climatic destruction influence of materials during operation on their long-term thermal productivity. Implementation of a new composite wall solution in construction was conducted. Originality. For the first time, the dependence of cyclic temperature effects on the long-term thermal productivity of expanded polystyrene concrete in a new composite wall made in a fixed formwork using light steel thin-walled structures was determined, which made it possible to establish its effective operation life. This scientific result makes it possible to reduce material consumption, ensure economy, increase operational reliability and energy-efficient properties, and increase the service life of the composite wall. Practical value. New solution for installing a composite wall made of expanded polystyrene concrete in a fixed formwork using light steel thin-walled structures was developed and its effective thermal operation within the legally established term was substantiated. The period of effective exploitation of expanded polystyrene concrete as the least durable component of a composite wall is substantiated. Approbation of this design was carried out by installing it on a real construction site, which showed an increase in the manufacturability of construction processes compared to traditional enclosing structures.