Paola Villoria Sáez

This study evaluates the feasibility of developing sustainable gypsum composites incorporating silica fume waste and fiber reinforcement for construction applications. The experimental program was divided into two phases. First, silica fume was incorporated into the gypsum matrix at addition levels ranging from 10% to 35% by weight of gypsum using water-to-gypsum ratios of 0.7 and 0.8. Dry bulk density, Shore C hardness, flexural strength, and compressive strength were determined according to standards. Subsequently, the most promising formulations were reinforced with polypropylene and glass fibers at dosages of 2% and 4% by weight of gypsum. Selected specimens were also analyzed by scanning electron microscopy (SEM). The results showed that silica fume can be successfully incorporated at levels of up to 35% while complying with the requirements established by UNE-EN 13279. Silica fume addition increased bulk density by up to 9.64% and improved surface hardness. Fiber reinforcement further enhanced mechanical performance, with the best formulation reaching compressive strength values close to 14 MPa, representing an increase of 27.14% compared with the corresponding silica-fume matrix. SEM observations confirmed matrix densification and satisfactory fiber–matrix adhesion. These findings demonstrate that the combined use of silica fume waste and fiber reinforcement is a viable strategy for producing gypsum composites with improved performance while promoting industrial waste valorization.

This study presents a data-driven evaluation of recycled-aggregate gypsum composites by examining the relationships between dry density, mechanical performance, thermal conductivity, and formaldehyde adsorption. Analysis of published experimental data shows that dry density is the primary parameter governing overall material performance. Compressive strength increases with density, whereas lower-density composites provide superior thermal insulation. An optimal multifunctional performance range was identified at 900–1100 kg/m³, where a favorable balance between strength and insulation efficiency is achieved. Aggregate type also influences performance: polymer-based aggregates produce the greatest density reduction, biomass-derived aggregates offer a balanced combination of properties, and mineral-based aggregates generally maintain higher stiffness. Assessment of environmental functionality indicates that conventional gypsum composites possess limited formaldehyde and CO₂ adsorption capacity, although biochar and other bio-based modifications can significantly enhance adsorption performance. These findings provide a practical framework for designing sustainable gypsum composites with balanced structural, thermal, and indoor air quality benefits.

Hospital buildings account for 60–80% of healthcare sector electricity consumption, yet robust causal evidence on the relationship between building energy efficiency and emissions per unit of clinical activity remains scarce. This study applies within–group fixed effects estimation to an unbalanced panel of 12 intermediate–complexity hospitals in Madrid, Spain (2016–2024; N = 107 hospital–year observations), controlling for activity volume and exogenous shocks. Cluster–robust standard errors and Wild Cluster Bootstrap inference address the limited number of cross–sectional units (N = 12). We propose a methodological correction for the artificial 74.6% discontinuity in Spain’s electricity emission factor (2020–2021) caused by regulatory change. The within–hospital building energy use intensity (EUIe) coefficient is β = 0.646 (p < 0.001), remarkably stable across six robustness specifications (range: 0.599–0.648; 8.2% variation). Wild Cluster Bootstrap confirms statistical significance despite 75% larger standard errors. A 20 kWh/m²·year EUIe reduction achievable through Heating, Ventilation and Air Conditioning (HVAC) retrofit in 1980s–era buildings translates into 13 kWh/stay savings, equivalent to 216 tCO₂/year for median–sized facilities (8.2% reduction). Within R² exceeds 0.97 across all specifications. Building envelope and HVAC retrofit constitute the dominant structural intervention for hospital Scope 2 emissions reduction. Facilities with EUIe > 150 kWh/m²·year should be prioritized for energy efficiency interventions using NextGenerationEU funds.

The construction industry significantly contributes to global greenhouse gas emissions, raw material extraction, and waste production. Implementing circular economy (CE) principles in this sector could greatly reduce these impacts. However, adoption within the industry remains slow due to barriers such as limited knowledge and experience. This chapter aims to assess and help overcome these obstacles by providing a comprehensive analysis of circular material usage principles and strategies in construction. It also highlights opportunities and enablers of change, including innovations and emerging technologies in recycling, digitization, robotic systems, new materials, and processing techniques. Four case studies illustrate the application of circular theory through a Bio-Building, Urban Mining and Recycling (UMAR) Experimental Unit, Open-spaced apartment, and an “Escuela Politécnica Superior”. The conclusions emphasize the need for strong regulatory frameworks, awareness initiatives, and international cooperation. Integrating technological advancements like AI, robotics, and blockchain is crucial for optimizing waste management. Additionally, education on circular practices is vital. By fostering global collaboration, standardizing circular construction approaches can lead to a more sustainable and resilient building industry.

This research develops a Waste Management System (WMS), which can be used during the design and construction stages of a building, and provides best practices for CDW prevention and management. For this, a literature review of studies dealing with best practices for CDW prevention and recycling was performed in order to develop the WMS, which is composed by eight procedures. Furthermore, the WMS was implemented in a construction company and individual interviews were conducted in order to know the main benefits and disadvantages of its implementation. The results of this study show that implementing a WMS improves CDW quantification, because the company obtains its own CDW generation ratio. The ratios will help construction agents to develop and write the CDW Management Plans and Reports and also achieve more accurate waste management costs. Finally, the integration of this CDW system with the company’s environmental management system supports the cohesion of the construction process organisation at all stages, establishes responsibilities in the field of CDW, and providing greater control of the entire process.

Many studies have developed technologies intended to automate the process toward improving sustainability and achieving a circular economy in the construction industry. Despite some research works that have been recently conducted to help construction agents in the management of construction and demolition waste (CDW), developing new CDW monitoring and traceability tools—through a collaborative and integrative approach—is still an urgent challenge. This paper developed a hybrid mobile app for the real-time traceability of construction waste generation and management, where agents involved in CDW management can work together and trace the generation and management of waste. For this, a research method was developed following three stages: (1) planning and design, including identification of the information to be incorporated in the app and the output data; (2) development of the app; and (3) app testing by several construction agents, stressing the benefits and limitations. The developed app allows not only estimating but also tracing the amount of CDW generated in a construction project, ensuring the correct management and control of the waste. In addition, it promotes collaborative work, as the agents involved in CDW management, i.e., construction companies, site managers, truck drivers, waste managers, and management plants, can work together and see in real-time the management of the waste.

A novel multifactor algorithm is developed with the aim of estimating GHG emissions in the EU countries and forecasting different future scenarios. This is created starting from (1) GDP, (2) population and (3) renewable energy share (RES). The determination coefficient (R²) of the multiple regression adopted reaches a value of 0.96; thus, only 4% of the GHG variation cannot be explained by the combination of the three variables. Germany is removed from the model after analysing the statistical outliers, as it presents an unusual behaviour within the European context. Also, France, Italy and Ireland are removed in the forecast analysis since they are characterised by corrected weighting values above the threshold value of the algorithm (0.156). The results show that GHG emissions decrease 14% in a low-growth-rate scenario, increase 24% in an average-growth scenario and increase 104% in a high-growth-rate scenario. Countries that improve the most are the ones that are currently underdeveloped in RES and are expected to decrease their population in the future (Croatia, Latvia, Cyprus and Greece). Other countries currently well positioned but with expected population growth (Sweden, Luxemburg and Denmark) or with expected intense GDP growth (Estonia and Malta) may lack decarbonisation levers. Therefore, policy makers should introduce additional subsidy schemes and tax exemptions in both developed and less developed countries to meet EU decarbonisation targets.