A sustainable solid waste-based cementitious system was developed using refining slag, steel slag, desulfurized gypsum, and granulated blast furnace slag (GBFS), and its low-temperature hydration behavior was investigated through a combined experimental and modelling approach. The strength development and microstructural evolution of the quaternary system under different curing temperatures were systematically analyzed. A temperature-dependent hydration kinetics interpretation was introduced to explain the variation in mechanical performance. The hydration characteristics were examined using X-ray diffraction (XRD), thermogravimetric–differential scanning calorimetry (TG–DSC), and scanning electron microscopy (SEM). The results indicate that curing temperature plays a dominant role in governing hydration kinetics and strength evolution. The compressive strength shows a clear positive correlation with temperature, which can be attributed to the accelerated formation of hydration products, mainly ettringite (AFt) and calcium silicate hydrate (C–S–H) gel. Under low-temperature conditions, the hydration process is significantly retarded due to reduced ion mobility and suppressed dissolution of solid waste components. The proposed mechanism suggests that refining slag contributes to the activation of the quaternary system by enhancing early-stage hydration reactions and improving structural densification. From a sustainability perspective, the developed system provides an effective pathway for large-scale utilization of industrial solid wastes while reducing dependence on conventional cement. The findings offer both experimental insights and a modelling-oriented interpretation of low-temperature hydration processes, providing a useful reference for the design and optimization of sustainable cementitious systems in cold-region engineering applications.
Understanding the mechanisms governing mutualistic interactions is essential for maintaining ecological stability and ensuring the sustainable management of natural ecosystems. To capture the nonlinear benefits inherent in such interactions, this study developed a mathematical model incorporating a Holling Type II functional response, which accounted for handling time and saturation effects. We established the ecological feasibility of the model by proving the non-negativity and boundedness of its solutions and conducted a rigorous qualitative analysis to investigate the existence and stability of equilibrium points. Numerical simulations across a range of ecological conditions supported the analytical results, while sensitivity analysis identified key pathways influencing population dynamics. Furthermore, an optimal control framework employing time-dependent control strategies was introduced to promote species coexistence. The model was solved numerically to evaluate the effectiveness of these interventions. Overall, the findings provide valuable insights for ecological planning and highlight the important role of mathematical modeling in advancing sustainable ecosystem management.
Deep excavations constructed in densely built urban environments are frequently supported by prestressed anchor systems, whose performance can significantly influence the stability of adjacent soil and structures. In this study, a finite element model was developed in PLAXIS 2D to investigate the mechanical response of an anchored deep excavation subjected to both static and seismic conditions. The excavation was retained by diaphragm walls and supported by three levels of prestressed anchors, while a five-story building was located at a distance of 10 m from the excavation boundary. Four representative prestress distribution patterns were considered, including uniform, decreasing, increasing, and mid-level maximum distributions. The influence of these prestressing schemes was evaluated through a comprehensive analysis of anchor forces, diaphragm wall lateral displacements, building horizontal displacements, and foundation settlements. The results indicated that the initial prestress distribution exerted a pronounced influence on the system behavior under static conditions. Reductions in wall deformation and building settlement were found to be strongly dependent on the magnitude and distribution of the initial prestressing forces. Among the investigated strategies, the decreasing prestressing scheme provided the most favorable overall performance. In contrast, the mid-level maximum distribution scheme exhibited comparatively lower efficiency in limiting excavation-induced deformations. Under seismic loading, however, the differences among the prestress distribution patterns became negligible. These findings suggest that optimization of anchor prestress distribution is primarily beneficial for controlling excavation-induced deformation under static conditions, whereas its effectiveness becomes considerably less pronounced when seismic effects dominate system behavior. The study provides practical guidance for the design and optimization of prestressed anchoring systems for deep excavations located in seismically active urban areas.
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