Key Engineering Materials Vol. 997

Abstract: The determination of drying period, compressive strength, and air-dry density represent crucial parameters for assessing the quality and performance of earthen construction materials. This paper explores the possibilities of using the ultrasonic method as a non-destructive testing technique applied to earthen materials (specimens, elements, or structures) to determine these properties. The method relies on the measurement of ultrasonic pulse velocity (UPV), which is influenced by factors such as density, elasticity, and curing process. By analyzing the propagation of ultrasonic waves through earthen samples, valuable insights can be gained regarding their drying period, compressive strength, and density. The drying period of earthen samples can be determined using the ultrasonic method by monitoring the changes in pulse velocity over time. As the moisture content decreases during the drying process, the velocity of ultrasonic waves increases due to the reduced presence of water. This allows for the estimation of the drying period without the need for time-consuming and destructive testing methods. Compressive strength is also a critical parameter in assessing the structural integrity of earthen materials. The UPV method offers a non-destructive approach to determine the compressive strength of earthen samples. This provides a valuable tool for quality control and assessment of earthen construction materials. Density is another important property that influences their performance and the UPV method can be used to determine the density of earthen materials by measuring the ultrasonic pulse velocity and analyzing its relationship with density. This non-destructive approach allows for quick and efficient estimation of the compactness and quality of earthen mixes. Overall, the ultrasonic method offers a non-destructive and efficient approach in determining the drying period, compressive strength, and density of various soil compositions. By measuring the pulse velocity and analyzing its relationship with these properties, valuable insights can be gained regarding the quality and performance of earthen construction materials. This method has the potential to significantly improve the assessment and quality control processes in earthen construction, leading to more sustainable and reliable structures associated with the earthen techniques.

Abstract: The purpose of research is to justify a calculation method for a stay rope of composite fiber structure with a breakage in fiber continuity. Research methodology is in constructing and solving a deformation model of a composite fiber stay rope with continuity breakage of one of its fibers. The calculation method of a stress-strain state of a stay rope of composite fiber structure considering the breakage of one of its fibers is established. The scientific novelty of research is in determining that the length of manifestation of a local disturbance of a stress-strain state of composite stay rope is proportional to a square root of a ratio of tensile modulus of a reinforcing element material and shear modulus of an elastic material that connects them. The practical value of the research is in that the calculation method allows reasonable prediction of a tractive capacity loss of a stay rope as a result of breakage of any of its reinforcing elements. The known value of residual tractive capacity allows reasonable selection of a safety margin for a stay rope, which ensures a sufficient level of reliability of a cable-stayed bridge.

Abstract: The current paper intends to present the directory lines and paths for the development and implementing construction eco-products, with advanced functionality (materials, elements and structures, models and technologies), considering the efficient and customized valorization of by-products and generated waste of local industries, in the context of National Strategy for Research, Innovation and Smart Specialization 2022-2027 regarding the transition to Circular Economy (EC). This represents one of the two main axes of the research project Nucleu Programme of the National Research Development and Innovation Plan 2022-2027, supported by MCID, "ECODIGICONS" project no. PN 23 35 04 01: “Fundamental-applied research into the sustainable development of construction products (materials, elements, and structures, as well as methods and technologies) that utilizes current national resources to enhance the eco-innovative and durable aspects of Romania's civil and transport infrastructure”, financed by the Romanian Government starting with the beginning of 2023. One of the novelties of the proposed approach of the project is considering the entrepreneurial environment of construction industry or complementary branches as essential stakeholders for the future results of the current scientific research. This dramatically changes the dynamic of the project, in terms of specific objectives, namely their focus on solving the current wastes’ problem by innovatively integrating them into competitive construction products with fast applicability and in accordance with support market requests. By the use of strategic management specific methods (e.g., External Environment (EE) and Internal Environment (IE) evaluation, SWOT analysis and derived specific strategies, etc.), four research directions have been identified for the valorization, at regional or even national level, of mineral additions (inert/hydraulically latent/pozzolanic, etc., derived from waste and industrial by-products (metallurgy, processing industry, construction/demolition, etc.)) by development of eco-smart materials and products for construction. The three directions are related to the considered mineral additions: Power plant ashes (fly ash and/or bottom ash), Steel slag and Garnet type residue Hence, the paper is willing to present the identification and the preliminary analyses of the specified research axes, plotted as necessary steps for achieving an intelligent and sustainable transition of the Romanian construction infrastructure. This approach implicitly ensures in the short and medium term, the increase of the degree of implementation of the principles of the Circular Economy (EC) in Romania, in the existing context which includes relevant factors like: geo-political, industrial and economic, urban and demographic, scientific, socio-cultural and environmental, in accordance with the imperatives of National, European and World Sustainable Development strategies.