Consideration of Critical Parameters for Improving the Efficiency of Concrete Structures Reinforced with FRP

Funding Information: This research was supported by the Polish National Agency for Academic Exchange no.: PPN/IWA/2019/1/00155/U/00001 (Iwanowska programme). Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Fibre-reinforced polymer materials (FRP) are increasingly used to reinforce structural elements. Due to this, it is possible to increase the load-bearing capacity of polymer, wooden, concrete, and metal structures. In this article, the authors collected all the crucial aspects that influence the behaviour of concrete elements reinforced with FRP. The main types of FRP, their characterization, and their impact on the load-carrying capacity of a composite structure are discussed. The most significant aspects, such as type, number of FRP layers including fibre orientation, type of matrix, reinforcement of concrete columns, preparation of a concrete surface, fire-resistance aspects, recommended conditions for the lamination process, FRP laying methods, and design aspects were considered. Attention and special emphasis were focused on the description of the current research results related to various types of concrete reinforced with FRP composites. To understand which aspects should be taken into account when designing concrete reinforcement with composite materials, the main guidelines are presented in tabular form.publishersversionpublishe

Large Panel System Technology in the Second Half of the Twentieth Century—Literature Review, Recycling Possibilities and Research Gaps

Large panel system (LPS) buildings, during the 1950s–1990s, were the most widespread among precast systems and are still a huge part of some national housing stocks. Disadvantages in characteristics, poor quality of all construction stages, sudden disasters and poor retrofit and repair techniques can result in demolishing some LPS buildings and thus the creation of huge amounts of waste. There is urgent need of evaluating the possibility of reusing the elements of LPS buildings. The novelty of the article is based on the formulation of research gaps in terms of recycling these buildings and the justification of such need. The authors reviewed the current state of knowledge regarding characteristics of LPS buildings, directions of retrofitting, durability and their locations within cities. The possibility of recycling elements of LPS buildings was analysed. The findings are that concrete load bearing panels, proved to be in satisfactory conditions in terms of strength and durability, have the possibility to be recycled into recycled coarse aggregate (RCA), so such waste could be beneficial for concrete. However, there are research gaps of such an application highlighted in the text. The authors suggest that conducting comprehensive basic research in this area could have significant benefits for the next generation of researchers and engineers

Large Panel System Technology in the Second Half of the Twentieth Century—Literature Review, Recycling Possibilities and Research Gaps

Large panel system (LPS) buildings, during the 1950s–1990s, were the most widespread among precast systems and are still a huge part of some national housing stocks. Disadvantages in characteristics, poor quality of all construction stages, sudden disasters and poor retrofit and repair techniques can result in demolishing some LPS buildings and thus the creation of huge amounts of waste. There is urgent need of evaluating the possibility of reusing the elements of LPS buildings. The novelty of the article is based on the formulation of research gaps in terms of recycling these buildings and the justification of such need. The authors reviewed the current state of knowledge regarding characteristics of LPS buildings, directions of retrofitting, durability and their locations within cities. The possibility of recycling elements of LPS buildings was analysed. The findings are that concrete load bearing panels, proved to be in satisfactory conditions in terms of strength and durability, have the possibility to be recycled into recycled coarse aggregate (RCA), so such waste could be beneficial for concrete. However, there are research gaps of such an application highlighted in the text. The authors suggest that conducting comprehensive basic research in this area could have significant benefits for the next generation of researchers and engineers

Consideration of Critical Parameters for Improving the Efficiency of Concrete Structures Reinforced with FRP

Fibre-reinforced polymer materials (FRP) are increasingly used to reinforce structural elements. Due to this, it is possible to increase the load-bearing capacity of polymer, wooden, concrete, and metal structures. In this article, the authors collected all the crucial aspects that influence the behaviour of concrete elements reinforced with FRP. The main types of FRP, their characterization, and their impact on the load-carrying capacity of a composite structure are discussed. The most significant aspects, such as type, number of FRP layers including fibre orientation, type of matrix, reinforcement of concrete columns, preparation of a concrete surface, fire-resistance aspects, recommended conditions for the lamination process, FRP laying methods, and design aspects were considered. Attention and special emphasis were focused on the description of the current research results related to various types of concrete reinforced with FRP composites. To understand which aspects should be taken into account when designing concrete reinforcement with composite materials, the main guidelines are presented in tabular form

Simulation of Depth of Wear of Eco-Friendly Concrete Using Machine Learning Based Computational Approaches

To avoid time-consuming, costly, and laborious experimental tests that require skilled personnel, an effort has been made to formulate the depth of wear of fly-ash concrete using a comparative study of machine learning techniques, namely random forest regression (RFR) and gene expression programming (GEP). A widespread database comprising 216 experimental records was constructed from available research. The database includes depth of wear as a response parameter and nine different explanatory variables, i.e., cement content, fly ash, water content, fine and coarse aggregate, plasticizer, air-entraining agent, age of concrete, and time of testing. The performance of the models was judged via statistical metrics. The GEP model gives better performance with R2 and ρ equals 0.9667 and 0.0501 respectively and meet with the external validation criterion suggested in the previous literature. The k-fold cross-validation also verifies the accurateness of the model by evaluating R2, RSE, MAE, and RMSE. The sensitivity analysis of GEP equation indicated that the time of testing is the influential parameter. The results of this research can help the designers, practitioners, and researchers to quickly estimate the depth of wear of fly-ash concrete thus shortening its ecological susceptibilities that push to sustainable and faster construction from the viewpoint of environmentally friendly waste management