The article presents the possibility of designing and industrial production of concrete for bridge construction. The examples of specific features designed for bridge concretes, which the acquisition is based on technologies less popular in Poland, better known from foreign experience is also shown. The implementation of modern concretes (lightweight aggregate, liquid concrete, concrete with silica fume) to bridge structures is discussed. The examples of concrete bridge structures are designed based on the PN EN standards.
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More eco-friendly and green concretes are needed to lower the climatic and environmental impacts of the growing demand for concrete. Despite the growing interest in using natural zeolite (NZ) in cement-based materials as an eco-friendly alternative for ordinary Portland cement (OPC), there is limited knowledge regarding the post-fire mechanical properties of natural zeolitic concrete (NZC). Hence, the development of a global model is desired to better explore the strength behavior of NZC after exposure to elevated temperatures. This study focused on the post-fire behavior of low-to-high-strength NZC specimens using a novel evolutionary method. Therefore, a widespread experimental program was designed to perfectly investigate the post-fire compressive strength of NZC. The experimental results were then used to develop an evolutionary-based machine learning (ML) model. To do so, the multivariate adaptive regression splines (MARS) method was hybridized with a new metaheuristic algorithm, the Horse herd Optimization Algorithm (HOA). Besides, the results of five different ML models, namely standalone MARS, M5P model tree (M5P), extreme learning machine (ELM), Gaussian process regression (GPR), and gene expression programming (GEP) were employed for comparison with the performance of metaheuristic-based MARS (Meta-MARS) model. Further external validation was conducted to show the superior performance of the Meta-MARS model. Also, a parametric study was conducted to demonstrate the robustness of the developed model. Moreover, an uncertainty analysis inspired by the Monte Carlo simulation (MCS) method was applied to the prediction results. Results of the modeling provided new insight into the post-fire behavior of NZC and agreed well with the experimental results. The satisfactory post-fire performance of NZC is promising and shows the climatic, environmental, and economic advantages of utilizing natural pozzolans.
W artykule omówiono zagadnienia dotyczące technologii prasoodpowietrzania mieszanek betonowych o matrycy cementowej – jej właściwości oraz projektowanie. Przedstawiono również technologię Pras-Bet, polegającą na połączeniu prasowania gorącej mieszanki betonowej z jednoczesnym jej próżniowaniem.
EN
The article discusses issues concerning the technology of pressurizing concrete mixtures with a cement matrix – its properties and design. The Pras-Bet technology, which combines the pressing of a hot concrete mixture with its simultaneous vacuuming, has been also presented.
Dynamiczny wzrost wykorzystania technologii tunelowania w obszarze budownictwa komunikacyjnego stawia przed technologami odpowiedzialnymi za projektowanie składu mieszanek betonowych oraz przed inżynierami odpowiedzialnymi za ich wbudowanie niespotykane w budownictwie kubaturowym i inżynierskim wymagania.
EN
A dynamic increase in using tunnelling technologies in the field of transport infrastructure engineering places on technologists responsible for concrete mix design and on engineers responsible for their laying demands that are unheard of in construction engineering.
Technologie tunelowania rozwijają się coraz dynamiczniej – liczba budowanych tuneli rośnie z roku na rok. Wykorzystywane w nich mieszanki betonowe muszą być specjalnie przygotowane do tego zadania. Artykuł stanowi drugą część rozważań w tym temacie – pierwsza została opublikowana w magazynie ,,Mosty" w nr. 6/19, s. 70-74.
EN
A dynamic increase in using tunnelling technologies in the field of transport infrastructure engineering places on technologists responsible for concrete mix design and on engineers responsible for their laying demands that are unheard of in construction engineering.
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