Circulating fluidized bed combustion (CFBC) ash, a byproduct typically generated from coal-fired CFBC power plant boilers, contains high content of free lime and anhydrite. Due to its chemical composition, CFBC ash exhibits self-cementing properties; however, its performance is limited. One approach to enhancing the self-cementing properties of CFBC ash is through the incorporation of mineral admixtures such as gypsum. This study investigated the influence of desulfurization gypsum (DG) on the self-cementing behavior of CFBC ash. To this end, paste and mortar specimens were prepared and evaluated for their hydration and mechanical characteristics. The hydration behavior was analyzed using isothermal calorimetry, thermogravimetric analysis (TGA), setting time measurements, and X-ray diffraction (XRD) analysis. Mechanical properties were assessed by measuring the compressive strength at various curing ages. Additionally, changes in microstructure were examined by evaluating the pore size distribution through mercury intrusion porosimetry (MIP). The experimental results indicate that the appropriate incorporation of DG enhances the hydraulic reactivity of CFBC ash and significantly improves the compressive strength.

This study aims to examine the thermomechanical properties of high-volume fly ash (HVFA) concrete for mass concrete applications. To achieve this, compressive strength, elastic modulus, adiabatic temperature rise, and thermal conductivity tests were conducted by varying the fly ash substitution ratio and Blaine fineness, along with the addition of limestone powder. Furthermore, 1200 × 1200 × 1200 mm cube-shaped mock-up members were fabricated to measure the temperature history and analyze the thermal crack index. Finite element analysis (FEA) was also performed to assess the temperature distribution and thermal stresses in HVFA concrete. The experimental results demonstrated that HVFA concrete achieves long-term compressive strength development due to the pozzolanic reaction of fly ash—a process that can be accelerated by utilizing more finely ground fly ash. Additionally, the compressive strength of HVFA concrete exhibited greater sensitivity to variations in curing temperature compared to that of normal concrete. The maximum adiabatic temperature rise of HVFA concrete decreased to 22.3 % of that of normal concrete, with this reduction becoming more significant as the fly ash substitution rate increased. The high fineness of fly ash and the addition of limestone powder increased the adiabatic temperature rise by 31.9 % and 14.9 %, respectively, compared to HVFA concrete with the same substitution rate. The mock-up test revealed that the temperature at the center of the HVFA concrete specimen decreased by 32.9 % relative to that of normal concrete and that resistance to thermal cracking improved with higher fly ash substitution rates. Further FEA validated the experimental results, demonstrating that fly ash substitution helps mitigate the risk of cracking by reducing thermal stresses in mass concrete structures.

Ground granulated blast-furnace slag (GGBS), a waste product generated during steel production, can be added as a substitute for cement in concrete to mitigate the environmental impact of the cement and steel industries. However, the use of GGBS is limited because it decreases the early strength development of cement or concrete. This study evaluated the performance of incorporating synthesized C-S-H nanoparticles to enhance the compressive strength, early hydration, and microstructure of cement composite. The synthesized C-S-H nanoparticles were produced at standard atmospheric pressure and room temperature. Heat of hydration, X-ray diffraction, and thermogravimetric analyses were conducted to investigate the hydration and mechanical properties of the cement containing the C-S-H nanoparticles. Further, mercury intrusion porosimetry was conducted to examine the pore structures. The experimental finding demonstrated that adding C-S-H nanoparticles accelerated the early hydration progress in the cement composites, thereby increasing their initial compressive strength.

High-volume fly ash cement exhibits drawbacks such as delayed hydration and reduced early-age compressive strength due to the replacement of large amounts of cement with fly ash. In recent years, various studies have been conducted to overcome these limitations by incorporating nanomaterials, such as nano-silica, to promote the hydration of cementitious systems. This study aims to investigate the effect of colloidal nano-silica on the hydration behavior of cement. Cement paste specimens were prepared with varying dosages of colloidal nano-silica to evaluate its influence. To examine the hydration characteristics and mechanical performance, compressive strength tests, isothermal calorimetry, and thermo-gravimetric analyses were conducted. Furthermore, the effect of colloidal nano-silica on the hydration of cement blended with fly ash was also examined. The experimental results revealed that the incorporation of colloidal nano-silica accelerated the hydration reactions in both ordinary and fly ash-blended cement pastes and significantly improved early-age compressive strength. In particular, the 7-day compressive strength of fly ash-blended cement mortar improved by 22.2% compared to the control specimen when 2% colloidal nano-silica was incorporated. The use of colloidal nano-silica appears to be a practical approach for enhancing the early strength of high-volume fly ash concrete, and its broader application and target expansion could contribute to the advancement of a low-carbon construction industry.

In contemporary memory semiconductor manufacturing, optimizing recipes has emerged as a crucial strategy to align with RE100 commitments, bolster ESG ratings, and substantially reduce operational costs. The current landscape demands the development of low-power manufacturing recipes that not only curtail energy consumption but also trim operational expenses, thereby augmenting overall profitability. This underscores the critical necessity for meticulous recipe optimization to ensure both sustainability and economic viability in the industry. In response to these challenges, there is an urgent need for a predictive framework capable of accurately forecasting optimal recipes. Such a framework is essential for facilitating the industry’s adaptation to dynamic technological environments and stringent environmental standards. By enabling proactive adjustments to manufacturing processes, this predictive approach ensures companies remain competitive while advancing comprehensive sustainability objectives. To address these needs, this work introduces a predictive framework specifically tailored to forecast recipe steps for plasma processes in semiconductor manufacturing. The framework’s efficacy was empirically validated using measurements from 300mm wafers in semiconductor mass production equipment. Plasma behavior was meticulously modeled, with simulations meticulously aligning with particle-in-cell models and Electron Monte Carlo collision simulations. These validations, conducted across both bulk plasma and sheath regions, confirmed the framework’s reliability and accuracy. Furthermore, the framework integrates a machine learning model to evaluate results under various recipe input conditions. This comprehensive approach not only enhances the understanding of plasma behavior but also facilitates the identification of optimal manufacturing conditions. Through meticulous recipe optimization, the framework minimizes undesirable effects such as backside chucking force and variations in thin film thickness, thereby improving overall manufacturing competitiveness and sustainability. Despite the inherent challenges and limitations, the predictive framework showcased significant potential to revolutionize manufacturing processes in the semiconductor industry. Its high predictive power positions it as a valuable tool for enhancing operational efficiency, driving informed decision-making, and ultimately advancing sustainability goals within the semiconductor manufacturing sector.

• Effect of TiO 2 powder type on the hydration and mechanical properties of cement is investigated. • De-pollution characteristics of cement mortar were evaluated based on NOx degradation. • TiO 2 powder in cement was found to accelerate the initial hydration reactions. • TiO 2 powder enhanced the early strength of the cement through a filler effect. • De-pollution characteristics were significantly influenced by the anatase-to-rutile ratio. This study was aimed at developing novel functional construction materials with NOx removal capabilities using TiO 2 powder. To this end, the effects of the chemical composition of TiO 2 powder on the hydration process and the mechanical properties of cement were investigated. The hydration characteristics of the cement were assessed by analyzing the setting time and heat of hydration, while the mechanical properties were evaluated by measuring compressive strength at different curing ages. Additionally, the NOx degradation performance was examined. The results demonstrate that TiO 2 powder accelerates the hydration of cement, enhancing the compressive strength during the early stages of hydration. Furthermore, the NOx degradation performance of mortar specimens was enhanced with the incorporation of TiO 2 powder. However, the extent of these improvements varied significantly depending on the chemical composition of the TiO 2 powder, with the composition ratio of anatase and rutile being particularly influential. When utilizing TiO 2 powder to enhance the performance of construction materials or impart new functional properties, it is advisable to consider the composition of the TiO 2 powder to ensure alignment with the intended performance improvement objectives.