Papers by Keyword: Durability

Abstract: This study relates to the development of geopolymer concrete (GPC) and empirical models which can be used to predict strength and durability under different curing temperatures. The binders and alkaline activators used for the GPC production were characterized to determine their physical and chemical properties. The partial and pure geopolymer concrete samples were produced. The partial replacement of Geopolymer concrete (GPC) samples was done with cement at varying percentages of 0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5 and 20% to determine the optimum cement stabilization. Fourier transform infrared spectroscopy (FTIR) results show key absorbance level at the zone between 950.1 and 3250.12 cm⁻¹. It means that enhancement of the laboratory-produced (bespoke) superplasticizer enhanced the performance of GPC by reducing the viscosity and enriching the flow behaviour of the concrete. The optimal geopolymer product showed substantial strength and durability enhancements at 70°C followed by declining values at temperatures above 70°C, indicating material deterioration. A positive correlation between hot-state temperature, strength and durability properties was also established. Furthermore, scrutiny of the model shows that overall dataset points for training and test sets are clustered close to the diagonal line, signifying that the model provides precise estimation of the strength and durability features. .

Abstract: In recent years, flexible strain sensors with high sensitivity and a wide sensing range have been developed for biosensors, wearable sensors, electronic skin, and soft robots. In this study, SR/CNT/SR composite-based sensors were fabricated using the sandwich manufacturing method. The sensors were then analyzed for electro-mechanical properties to test their performance. The flexible strain sensor showed a high sensitivity of 76.60 at 0-80% strain range. In addition, the sensor also showed a high linearity of 0.978 in one linear region. The sensor also constantly changes relative resistance at 10 cycles in the 0-40% range. While in the 45-80% strain range, the relative resistance value fluctuates. This is due to the large crack in the sensor when stretched. This sensor also has a fast response time of about 80 ms and a fast recovery of around 95 ms. This flexible strain sensor is also stable for durability testing at 500 loading and release cycles.

Abstract: Material abrasion is a critical consideration in product design, manufacturing, and maintenance because it has a high impact on several properties. When it comes to the abrasion of polymer yarns, insight into the behaviour of yarns due to constant abrasion is important for ensuring final product quality, performance, and customer satisfaction. For this study, a group of polymer yarns is selected. The yarns differ in raw material, as well as the yarn type. Within the experiment selected yarns in both single condition and within the fabric structure were conducted to different abrasion tests. The study findings reveal that yarn type, raw material composition, and additional treatments significantly influence abrasion resistance. Recycled polyester yarns demonstrate comparable, if not superior, abrasion resistance to conventional ones, making them viable for various applications.

Abstract: Limestone fillers are increasingly recognized as a sustainable alternative to cement and sand in mortar and concrete mixtures, driven by environmental concerns over the excessive use of natural resources and raw materials. This study investigates the potential exploitation of different limestone fillers, waste products of the quarrying industry, in the production of cementitious composites. The investigation includes the physico-mechanical characterization of a number of mixtures with different percentages of limestone fillers used as partial replacement to sand. The results show that increasing the limestone filler content negatively influences the mechanical performance of the hardened end-products, decreases their density and increases their open porosity. At the same time, increased clay particle content in the limestone filler decreases the workability of the fresh mixtures.

Abstract: This paper focuses on the multicriteria software optimization of reinforced concrete floor slabs, especially in terms of environmental impacts and cost. The economic aspect is essential to ensure that the environmentally friendly design option is also cost effective. The durability of the structure is also considered as it significantly affects its overall environmental footprint. Increased durability reduces the frequency of repairs and extends the service life before demolition and reconstruction are required, thereby spreading the environmental impacts of the initial construction over a longer period. The software tool used for optimization was developed in previous work, and this paper extends its application to lightweight floor slabs and prestressed hollow core slabs. This extension aims to enhance the practical usability of the optimization algorithm. Lightweight floor slabs, particularly for large spans, can reduce both environmental burdens and construction cost. This paper describes the extension of an optimization algorithm to identify the most advantageous floor design in terms of environmental impact and cost. It also examines the benefits of floor slab lightweighting and provides general recommendations for optimizing reinforced concrete floor slabs.

Abstract: This paper presents a comprehensive examination of foamed concrete and its use in contemporary building technology. Due to its lightweight and porous properties, foamed concrete provides notable advantages such as improved thermal insulation, soundproofing, and decreased structural load. The assessment documents progress in foamed concrete technology, encompassing enhancements in mix composition, resilience, and environmentally sustainable manufacturing techniques. Notwithstanding its benefits, the presence of problems such as variable quality control, absence of standardized testing, and long-term performance problems is emphasized. The analysis also examines the many uses of the material, ranging from structural elements to non-structural filler, and its contribution to sustainable building methods. The paper suggests future research paths that highlight the need of conducting further study on performance optimization and expanding the range of application scenarios. By effectively tackling these obstacles and capitalizing on continuous technical progress, foamed concrete has the capacity to greatly influence modern building methods, providing a range of environmental and economic advantages.

Abstract: The construction industry is facing increasing pressure to adopt sustainable and eco-friendly practices in response to the growing concerns over environmental degradation and climate change. Among the various innovative materials being explored, geopolymer mud blocks have emerged as a promising alternative to traditional construction materials such as cement and fired clay bricks. These blocks are characterized by their eco-friendly composition, which typically involves the use of industrial by-products like fly ash, metakaolin, and other aluminosilicate materials, activated through an alkaline solution. This process results in a material that not only exhibits superior structural integrity but also significantly reduces the carbon footprint associated with construction.This paper provides a comprehensive review of the material composition of geopolymer mud blocks, detailing the various raw materials used and the chemical reactions that confer strength and durability to the blocks. The review also delves into the structural properties of these blocks, including their compressive strength, thermal insulation capabilities, and resistance to environmental factors such as moisture and temperature fluctuations. Additionally, the paper explores the ecological impacts of geopolymer mud blocks, emphasizing their potential to reduce greenhouse gas emissions, minimize resource depletion, and promote the use of industrial waste, thus contributing to a more circular economy.Finally, the paper looks forward to the future prospects of geopolymer technology in the construction industry, suggesting potential pathways for overcoming the current limitations and further enhancing the sustainability of construction practices. By providing a holistic view of geopolymer mud blocks, this review aims to contribute to the growing body of knowledge on sustainable construction materials and to support the transition towards greener building practices on a global scale.

Abstract: A construction building's structural integrity, material quality, workmanship, and conformity to design specifications were all assessed qualitatively. Potential problems like cracks, corrosion, or subpar construction techniques were found during the examination through visual inspections, material testing, and documentation analysis. Guidelines for upkeep, fixes, or structural improvements were offered to guarantee the building's longevity, security, and adherence to rules. The evaluation sought to improve the building's durability, functionality, and occupant safety while correcting any flaws to preserve structural integrity.

Abstract: Iron tailings are the main component of industrial solid waste. The long-term storage and landfill of iron tailings have caused great pressure on the environment. In this paper, Anshan type high-silicon iron tailings and fly ash were used as the main raw materials to prepare geopolymer. The activity of raw materials was determined by XRD, and geopolymer was prepared by high temperature water culture. The effect of iron tailings content, liquid-solid ratio and curing temperature on geopolymer mechanics was studied. The optimal ratio was determined by regression equation analysis with compressive strength as index. The reaction process of geopolymer was studied through microscopic analysis (XRD, SEM, FTIR), and the changes before and after the reaction of geopolymer were compared to prove the reaction degree of geopolymer, and representative specimens were selected to verify the strength changes under different ratios. The durability of the prepared polymers was tested, and the relevant parameters were determined. The gelling material with good freezing resistance and chemical corrosion resistance was successfully prepared, and the industrial waste was transformed into treasure.

Abstract: The durability of degradable polylactide and its composites is a primary bottleneck for its long-term applications. This work reports the investigation results on the durability of short jute fiber/polylactide (PLA) composite material in indoor conditions performed for over 15 years. The material was fabricated in July 2006, using the film stacking hot pressed method. It was exposed in an indoor environment for a durability test. The appearance and the microstructure of the material were inspected by using a scanning electron microscope. Surface reticular micro-cracks and small pits on the resin-rich region of the composite plate were observed. The thickness of the composite plate did not show visible change. Tensile strength was tested by using a universal tensile test machine. Tensile stress at the break did not show an obvious reduction compared with the initial strength obtained 15 years ago. The results demonstrate that jute fiber/polylactide composite has good durability in moderate environments.