This article addresses the technical, aesthetic, and strategic problem of the limited attention paid to design and selection of materials in photovoltaic system (PSS) support structures despite their direct impact on the efficiency, durability and economic viability of these systems. As the costs of modules and electronic components continues to decrease, the structural elements acquire greater weight in the total cost and long-term performance. Our research comprehensively analyzes the mechanical, environmental, and regulatory factors influencing material selection and structural design in PV mounting systems. The PRISMA methodology was used to perform a systematic review of 122 articles published between 2018 and 2025, which were classified along two axes: materials (mild steel, galvanized steel, aluminum, polymers, and composites) and structural design (angle, orientation, loads, support typology, and adaptation to the environment). The results show that an adequate match between design and climatic conditions improves system stability, efficiency, and service life. With the support of digital modeling and advanced simulations, we identify trends towards modular, lightweight, and adaptive solutions, particularly in architectural applications (BIPV). This work provides a robust and contextualized technical framework that facilitates informed decision-making in solar energy projects, with direct implications for the sustainability, structural resilience, and competitiveness of the PSS sector in different geographical regions.

Developing sustainable ceramic formulations that integrate industrial by-products addresses the high energy and raw material demands of refractory manufacturing while advancing circular economy goals. This study investigates the recycling of chamotte waste from rejected fired electrical porcelain as a partial substitute (5 and 10 wt.%) for flint clay in aluminosilicate refractory castables. Samples were fired at 110, 815, 1050, and 1400 °C and evaluated for bulk density, apparent porosity, cold crushing strength, and flexural strength. Microstructural and mineralogical changes were analyzed by SEM and XRD. Incorporating 10 wt.% chamotte waste fostered an in situ mullite-reinforced microstructure, enhancing mechanical strength (58 MPa—CCS, 18.8 MPa—MOR) and lowering porosity (24.4%), demonstrating chamotte’s dual role as recycled raw material and reinforcement phase for densification and durability. These properties matched or surpassed those of the conventional formulation, with strength improvements of up to 44%. The findings demonstrate that high-temperature industrial waste can be effectively valorized in advanced refractories, reducing reliance on virgin raw materials, diverting waste from landfills, and promoting industrial symbiosis within the ceramics and metallurgical sectors.

Magnesia-dolomite refractories have emerged as sustainable alternatives to traditional carbon- or chromium-containing linings in steelmaking and cement industries. Their outstanding thermochemical stability, high refractoriness, and strong basic slag compatibility make them suitable for converters, electric arc furnaces (EAF), and argon–oxygen decarburization (AOD) units. However, their practical application has long been constrained by hydration and thermal shock sensitivity associated with free CaO and open porosity. Recent advances, including optimized raw material purity, fused co-clinker synthesis, nano-additive incorporation (TiO₂, MgAl₂O₄ spinel, FeAl₂O₄), and improved sintering strategies, have significantly enhanced density, mechanical strength, and hydration resistance. Emerging technologies such as co-sintered magnesia–dolomite composites and additive-assisted microstructural tailoring have enabled superior corrosion resistance and extended service life. This review provides a comprehensive analysis of physicochemical mechanisms, processing routes, and industrial performance of magnesia–dolomite refractories, with special emphasis on their contribution to technological innovation, decarbonization, and circular economy strategies in high-temperature industries.

The global reliance on coal-fired power generation continues to produce vast quantities of fly ash, exceeding 500 million tons annually, with limited recycling rates. Given its high silica (SiO₂) and alumina (Al₂O₃) contents, fly ash represents a promising alternative raw material for sustainable refractory production. In this study, four aluminosilicate refractory castables were formulated using bauxite, calcined flint clay, kyanite, calcium aluminate cement, and microsilica, in which the fine fraction of flint clay was partially replaced by 0, 5, 10, and 15 wt.% fly ash. The specimens were dried at 120 °C and sintered at 850, 1050, and 1400 °C for 4 h. Their physical and mechanical properties were systematically evaluated, while phase evolution and microstructural development were analyzed through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results revealed that the incorporation of 10 wt.% fly ash (10FAC) provided the optimal balance between densification and strength, achieving compressive strengths of 45.0 MPa and 65.3 MPa after sintering at 1050 °C and 1400 °C, respectively. This improvement is attributed to the formation of a SiO₂-rich liquid phase derived from fly ash impurities, which promoted the in-situ crystallization of acicular secondary mullite and enhanced interparticle bonding among corundum grains. The 10FAC castable also exhibited only a slight increase in apparent porosity (26.39%) compared with the reference (25.74%), indicating effective sintering without excessive vitrification. Overall, the study demonstrates the technical viability of using fly ash as a sustainable substitute for flint clay in refractory castables. The findings contribute to advancing circular economy principles by promoting industrial waste valorization and resource conservation, offering a low-carbon pathway for the development of high-performance refractory materials for structural and thermal applications in energy-intensive industries.

Grounding Systems (GS) play a critical role in electrical safety, lightning protection, and the reliable operation of power and renewable energy infrastructures, particularly in high-resistivity soils. In this context, Ground Enhancement Materials (GEM) are widely used to reduce soil resistivity and improve grounding performance. This systematic review analyzes and synthesizes recent advances (2018–2025) in GEM applied to GS, with emphasis on their electrical performance, durability, and environmental sustainability. The review covers conventional GEM, industrial waste-derived materials, and hybrid formulations, evaluating their effectiveness under different soil types and moisture conditions. Comparative analysis of the literature indicates that GEM derived from industrial byproducts and hybrid composites often exhibit superior long-term resistivity reduction due to enhanced moisture retention and material-soil interactions, especially in clay-rich and heterogeneous soils. Sustainability considerations such as environmental impact, material availability, and long-term stability are increasingly influencing GEM selection and design. Overall, this review provides a structured framework for understanding the factors governing GEM performance while highlighting current trends, challenges, and future research directions in the development of sustainable grounding solutions.

This study addresses a key unresolved question in alkali-activated materials: how externally supplied calcium from limestone influences calcium-induced hybrid gel formation under NaOH-only activation in precursor systems with different initial calcium availability. Unlike previous studies focusing mainly on strength development or using combined alkaline activators, this work establishes a composition-dependent mechanistic framework linking calcium availability, reaction kinetics, microstructural evolution, and engineering performance. Limestone additions (5–10 wt.%) were incorporated into fly ash (FA0) and slag–fly ash (FAS0) binders activated with 8 M NaOH and cured at 65 °C. In the low-calcium fly ash system, compressive strength increased from 29 to 38 MPa (≈30%), with nearly 90% of the ultimate strength achieved within the first 24 h. In contrast, slag-containing binders exhibited strength variations below 5%, indicating limited additional benefit once sufficient calcium was intrinsically available. Integrated characterization (SEM/EDS, XRD, FTIR, isothermal calorimetry, and TGA–DSC) consistently supports the progressive transformation from predominantly N–A–S–H gel toward hybrid calcium-containing binding environments. The combined evidence suggests that localized calcium availability associated with limestone accelerates hybrid gel formation and microstructural densification rather than acting solely as an inert carbonate filler. These findings provide practical guidelines for designing low-carbon hybrid alkali-activated binders with tailored reaction kinetics, optimized engineering performance, and improved material efficiency.