The development of self-compacting concrete (SCC) has revolutionized modern infrastructure by facilitating the construction of high-strength and intricate structures such as rigid pavements, bridges, tunnels, and skyscrapers since it has superior flowability and capacity for self-consolidation without external vibration. Despite all these advantages, the inherent brittleness and poor energy absorption capacity are significant shortcomings when it is subjected to impact and dynamic loading. The purpose of this investigation is to identify and ascertain the performance of an asphalt emulsion (AE) as a toughening agent on SCC to increase its energy absorption capability without significantly affecting its mechanical properties and fresh characteristics. For this study, five mixes were cast, including a reference mix and four SCC mixes containing 5, 10, 15, and 20% AE content (by weight of cementitious material). Fresh properties were measured using slump flow and J-ring tests, while hardened concrete properties included mechanical behaviour (stress-strain curve, toughness index), microstructure analysis (pore size distribution, XRD), and response surface methodology (RSM)-based modelling. This study shows that AE effectively enhances the postpeak deformation behaviour and the energy dissipation of SCC at the cost of a small reduction in compressive strength. The toughness index of the mixture with 5%, 10%, 15%, and 20% AE was improved by 5.21%, 17.00%, 24.13%, and 39.52% compared with the control, indicating an enhanced ductility and toughness with increasing AE content. In addition, the fresh properties were all within the permissible limits for SCC mixtures, suggesting that the workability of SCC was not negatively influenced by the addition of AE. Two very reliable models for predicting the slump flow, compressive strength, and flexural strength were obtained based on the RSM analysis and demonstrated a strong correlation between laboratory and predicted values. The optimum amount of AE based on both the fresh and hardened state performance of the concrete should be 10%. In addition, a suitable dosage of 10% AE can contribute to a compromise of improved toughness and energy dissipation, sufficient mechanical performance, and workability. The results suggest that AE is a promising, eco-friendly, and low-cost admixture for enhancing the toughness and impact resistance of concrete for durable and resilient transportation and civil infrastructure.
The construction sector accounts for 37% of global greenhouse gas emissions and consumes about 50% of all materials extracted worldwide. In the European Union, construction and demolition waste reach 40% of the total annual waste generated. Buildings often have an actual service life significantly shorter than their intended design life, intensifying environmental and economic impacts. Conventional design models that disregard building adaptability and the possibility of disassembly result in inflexible, short-lived constructions with high environmental impact. Given this context, the present study aims to investigate the uses of Building Information Modeling (BIM) in projects oriented towards Design for Adaptability and Deconstruction (DfAD), through a systematic literature review. The research is based on the principles of the Circular Economy, which proposes strategies to eliminate waste, keeping materials in continuous use, and regenerating natural systems. DfAD emerges in this context as a design approach that promotes flexibility of use, disassemblability, and the reuse of building components, integrating circularity into construction industry practices. BIM, in turn, is examined as a fundamental support strategy for enabling these principles. The systematic review included 65 selected articles, which were analyzed and organized into six main thematic axes: (a) Design; (b) Fabrication, construction, and assembly; (c) Deconstruction, disassembly, and end of life (EOL); (d) Tools and Technologies; (e) Building life cycle analysis; and (f) Materials Passport. To synthesize the analysis, a conceptual scheme of 30 key customized BIMfAD model uses was developed, providing a structured overview of their application across the building life cycle.
The construction industry is a major consumer of natural resources and a generator of waste, resulting in significant environmental impacts. At the same time, the sector faces management challenges, including project inconsistencies, missed deadlines, budget overruns, and environmental degradation. The Circular Economy (CE) has shown promise in addressing inefficient resource use and minimizing negative environmental impacts, while agile project management aims to deliver more successful and efficient projects. This paper explores the synergy between the agile approach and CE in the construction industry through a content analysis of CE practices and agile attributes for construction projects, examining positive and negative interactions. The results show a positive synergy between the two approaches, highlighting the use of digital technologies to promote CE and the design of modular buildings, focusing on the early phase of the life cycle (design), which has the most relationships. Flexibility and transparency were the agile attributes most associated with CE practices, with the "management processes" category highlighted as the most interactive. The study suggests adapting the Scrum agile framework to manage circular innovation projects in parallel with construction to promote the transition from a linear to a CE model in the construction industry.
The construction sector faces pressing environmental challenges driven by high resource consumption, elevated waste generation, and significant greenhouse gas emissions. The circular economy (CE) has emerged as a restorative and regenerative alternative to traditional linear models, promoting resource efficiency, material recirculation, and long-term sustainability. Effective integration of CE principles into the built environment, however, depends on the availability of assessment methods capable of measuring circularity, evaluating material flows, and identifying regeneration opportunities. This paper presents a theoretical analysis of existing sustainability assessment methods, including BREEAM, LEED, and DGNB, and evaluates their capacity to operationalise circularity in the construction sector. Results show that while current tools incorporate aspects of sustainability, they lack specific metrics to measure circularity indicators, such as material loops, design for disassembly, resource recovery potential, and system regeneration. A conceptual framework and an expanded set of indicators are proposed to enhance the assessment of circularity and support transitions toward circular construction practices. The paper contributes to the theoretical foundations needed to guide policy development, industry adoption, and collaborative strategies in circular built-environment systems.
The transition toward a Circular Economy (CE) in the construction sector is essential for addressing escalating pressures related to resource scarcity, climate change, and environmental degradation. This study investigates the development and monitoring of circular policies within the built environment by examining international initiatives and evaluating policy instruments through a multi-level governance perspective. A systematic literature review was conducted to identify regulatory frameworks, strategies, and evaluation tools implemented across different regions. The findings reveal that CE policies remain predominantly focused on end-of-life waste management, while upstream strategies-such as design for disassembly, modularity, material traceability, and digital integration-are still underutilized. Most initiatives lack comprehensive monitoring indicators and rarely integrate micro (local), meso (regional), and macro (national) levels in a cohesive feedback loop. The analysis demonstrates that effective CE implementation requires synergistic policy packages supported by robust data, digital technologies, and multi-stakeholder collaboration. The study concludes that advancing circularity in the built environment depends on the development of adaptive, evidence-based policies capable of aligning national agendas with local realities and ensuring continuous evaluation across the construction life cycle.
Improving the energy performance of existing buildings while preserving their architectural value represents a major challenge in achieving European Union climate targets and advancing circular economy (CE) principles in the construction sector. This challenge is particularly pronounced in culturally protected buildings, where conventional insulation systems may compromise authenticity and material integrity. This study investigates the potential of aerogel-based thermal insulation materials, with a focus on silica aerogel plaster, as a non-invasive solution for sustainable renovation of heritage buildings. A comparative evaluation of commercially available nanomaterial-based insulation systems was conducted based on thermal conductivity, environmental impact, required thickness, and compatibility with conservation criteria. Silica aerogel thermal plaster was identified as the most suitable solution for façade applications in protected structures. Its performance was assessed through dynamic energy simulation of the Macedonian Academy of Sciences and Arts building in Skopje, a representative example of post-earthquake modernist heritage architecture. Two scenarios were analyzed: the existing condition and an improved model incorporating aerogel façade insulation and upgraded envelope elements. Simulation results indicate a 48.3% reduction in annual heating energy demand, a 10% reduction in cooling energy consumption, and a 15% decrease in overall electricity use. Total annual CO₂ emissions were reduced by 35%, accompanied by significant operational cost savings. The findings demonstrate that aerogel-based plaster enables substantial energy and environmental improvements while maintaining architectural authenticity and reversibility, thereby supporting both energy efficiency goals and circular economy principles in heritage renovation.
Construction and demolition waste represents one of the largest waste streams worldwide and plays a central role in achieving circular economy objectives in the built environment. This study aims to systematize and synthesize recent knowledge on the potential for reuse and recycling of key construction materials - steel, timber, concrete, and bricks and blocks - at the end of their service life. The research is structured in two papers: Part 1 focuses on regulatory frameworks, recycling rates, and reuse and recycling practices for steel and timber, while Part 2 addresses concrete and bricks and blocks. The objective was to identify opportunities for reuse and higher-value recycling as more effective circular solutions. The results indicate that, although the European regulatory framework for C&DW is well developed and aligned with circular economy principles, significant gaps remain, particularly the lack of harmonized end-of-waste criteria and quality standards for most material fractions. Consequently, high reported recovery rates often conceal downcycling practices and limited material circularity. Steel exhibits consistently high recycling rates, driven by strong market demand and established regulatory criteria, while direct reuse remains marginal. In contrast, timber recovery is dominated by energy recovery, with material recycling and reuse constrained by heterogeneous material quality, limited classification systems, and insufficient policy support.
The construction industry is responsible for approximately one-third of greenhouse gas emissions and over 50% of natural resource consumption. In this context, the Circular Economy (CE) emerges as a strategy to promote economic development while reducing dependency on natural resources. Tools such as the Materials Passport (MP) are crucial in facilitating this transition. The MP is a digital solution that collects data on materials, aiming to facilitate their recovery and reuse. In Brazil, it is still underutilized. Therefore, understanding the perceptions of Brazilian professionals regarding this tool is crucial for its broader implementation in the sector. This study analyzes the views of four professionals on the concept and process of modeling an MP, based on interviews. The interviews consist of a validation method defined as a functional test, which examines the desired parameters from the user's perspective without requiring the user to understand the system's internal structure. The results highlight two main obstacles. First, modeling processes and information management still need to evolve to achieve market applicability. Second, tools applicable to CE in construction, such as the MP, must be accompanied by greater awareness of CE, MP, and sustainability concepts within the sector.
Polyethylene terephthalate (PET) straps cannot be mechanically recycled in certain regions where the required technology is unavailable or where the scale of operations is insufficient to ensure economic viability. They tend to be accumulated in the recycling chain, from industrial generators, to waste separation plants and even recycling plants and landfills. However, PET straps could be used in construction as aggregates for concrete paving blocks or in panels with epoxy resin binder. This study evaluates two open-loop alternatives for recycling discarded PET straps into construction products considering Political, Economic, Social, Technological, Environmental, and Legal factors of the PESTEL framework. The political, social, and legal conditions were comparable for both alternatives, whereas the economic and environmental assessments favoured the panel-based solution. However, the technological analysis indicated that panel production remains at an early stage of development, introducing uncertainty and potentially delaying its large-scale implementation. In contrast, the manufacturing process for paving blocks is based on established and readily available technology, allowing for immediate implementation under current conditions.
The increasing demand for sustainable and efficient construction practices has accelerated the adoption of advanced digital technologies across the sector. This paper presents a conceptual framework based on a systematic theoretical review of the combined potential of Artificial Intelligence (AI), Virtual Reality (VR), and Augmented Reality (AR) to transform construction workflows and support the transition to circular, resource-efficient building practices. VR enhances design comprehension and stakeholder communication through immersive visualization, while AR enables real-time onsite guidance and augmented inspections, improving accuracy and reducing execution errors. Complementing these capabilities, AI introduces predictive analytics, automated defect detection, and data-driven optimisation of materials, labour, and lifecycle performance. By integrating these technologies into a unified digital ecosystem, construction projects can significantly reduce waste, improve quality, and strengthen decision-making throughout the project lifecycle. The proposed conceptual framework illustrates how immersive environments and intelligent analysis can operate in synergy to support sustainability objectives, including lifecycle extension, improved resource efficiency, and alignment with circular economy principles. No empirical component is included; empirical validation of the framework in real construction projects is identified as a primary direction for future research. This study contributes to the ongoing digital transformation of the construction industry by articulating a holistic, lifecycle-spanning perspective on integrating VR, AR, and AI, providing a replicable foundation for future research and practical implementation.
Prefabricated reinforced concrete (RC) systems are efficient in terms of construction, but their durability is highly dependent on the behaviour of joint regions with several material interfaces. This research examines the chloride-induced corrosion performance of prefabricated beam-column joints connected by grouted sleeves, as compared with traditional cast-in-situ counterparts. The study employed an experimental-analytical method with wetting-drying cycles in a 3.5% NaCl solution to represent severe environmental exposure. The findings show that prefabricated joints demonstrate faster corrosion, with corrosion initiation 40-60% earlier than in cast-in-situ joints. The rate of corrosion was about 2.8 times faster, and the chloride diffusion coefficient increased by 2.5 times, confirming increased transport via the interfacial regions. Damage was concentrated at the sleeve interfaces, with a Damage Localisation Index (DLI) of about 0.62, and led to wider cracks than observed in traditional structures (more than twice the width). This study shows that the corrosion behaviour of prefabricated joints is largely controlled by the interface rather than the bulk properties. Targeted application of duplex stainless steel (Grade 2205) in key areas was effective in delaying the onset of corrosion and in diminishing its impact, showing the benefit of using this material in critical areas. The research provides evidence of interface-controlled corrosion and highlights the need for interface engineering and material design to enhance the sustainability of prefabricated concrete structures.
This study investigates the feasibility of employing municipal solid waste incineration bottom ash (WBA) as the sole precursor for producing alkali-activated binders (AA-WBA), with the aim of developing low-carbon mortars and concretes for non-structural urban applications within a circular-economy framework. The precursor, originally in the 8-30 mm particle-size fraction reported in previous studies, was milled to obtain material below 125 µm. A series of activation conditions was examined by varying the NaOH concentration, the NaOH-to-sodium-silicate ratio, and the liquid-to-solid ratio, together with three precursor particle-size ranges (≤63 µm, 90-100 µm, and 100-125 µm). The optimal formulation (1:4/0.6/4 M; 90-100 µm) achieved satisfactory mechanical performance in paste form and developed a dense microstructure characterised by the formation of C-(A)-S-H/N-A-S-H gels, as evidenced by TGA, FT-IR, and SEM analyses. As a proof of concept, this binder was used to manufacture a full-scale concrete pedestrian paving element, which exhibited adequate mechanical performance for outdoor pedestrian use at 28 days. Leaching and ecotoxicity tests indicated low metal release and no significant toxic effects, thereby demonstrating the environmental safety of the material and its potential contribution to more sustainable construction systems.
In this study, the vertical displacement at the midspan of a beam is monitored using a VL6180X laser distance sensor within an experimental-theoretical framework. The proposed measurement system is simple and well suited for the acquisition of both static and dynamic structural responses. The measured data are recorded as a continuous digital signal and processed in the Arduino environment. The time-domain signals are then exported to MS Excel for further analysis using the Fast Fourier Transform (FFT). The Discrete Fourier Transform (DFT) and its inverse (iDFT) are implemented in order to validate the measured response in both the time and frequency domains. The comparison between the DFTand FFT-based analyses indicates only negligible differences in the evaluated midspan displacement for the same vertical signal.
This study investigates the structural performance and design considerations of various connection types used in curtain wall and balustrade systems. Emphasis is placed on horizontal-to-vertical and vertical-to-beam/floor connections, which are critical for transferring loads and maintaining fa & ccedil;ade integrity. The paper evaluates different connector configurations, ranging from shear-only to combined shear-moment. It examines the use of extruded steel brackets, including fin plates and shoe brackets, in detailed applications. Thermal loading is addressed through the incorporation of slotted holes and expansion provisions, ensuring serviceability under fluctuating temperature conditions. The study also explores the use of custom-fabricated brackets, kicker supports, and steel inserts in areas with spatial constraints. Additionally, anchorage design is analyzed, with attention to edge distances, embedment depths, and concrete strength to prevent brittle failures, particularly in glass-supported systems. Finite Element Analysis (FEA) is used to validate connection performance under service and ultimate loading conditions. The findings offer practical insights for engineers and designers aiming to ensure robust, compliant, and efficient curtain wall connections.
Prefabricated concrete elements are widely used for pavement surfaces on urban and local roads. This paper presents an analysis and comparison of pavement structures composed of these elements, focusing on displacements under continuous driving loads and braking forces, to analyze the behavior of prefabricated concrete elements and overall pavement structures under different load actions. The study emphasizes the importance of accounting for braking forces in pavement design, as they significantly influence surface displacements and overall performance. The behavior of the pavement is simulated using five structural configurations, two joint widths, two subbase types, and four subgrade types via the finite element method. Results indicate that elements with 3 mm joints exhibit smaller displacements than those with 5 mm joints and that the geometry of the interlocking significantly influences the deformation under braking-type loading. Furthermore, crushed stone subbases perform better in controlling vertical movements, while natural sand-gravel subbases provide improved horizontal movement behavior.
A numerical analysis was performed to investigate the bearing capacity and settlement behaviour of shallow foundations on overconsolidated clays. Finite element analyses were conducted in PLAXIS 2D using two constitutive soil models: the Modified Cam Clay and the Hardening State Parameter (HASP) model. The HASP model, implemented as a user-defined constitutive formulation, introduces state-dependent hardening within the critical state framework to represent the stress-strain behaviour of overconsolidated clays. The study reproduced field load tests on two shallow footings (A and B) at the Bothkennar research site, supported by comprehensive measurements of settlements and pore-water pressures. All soil parameters were adopted directly from published laboratory data, without further calibration. The analyses focused on the load-displacement response, time-dependent settlements under sustained loading, and the development and dissipation of excess pore-water pressures. The HASP model provided a realistic prediction of the measured field behaviour, showing good agreement with observations and demonstrating its capability to capture the coupled hydro-mechanical response of overconsolidated clays.
Graphic statics is a method for analyzing and designing structures based on the geometric representation of equilibrium conditions, where both forces and structural forms are depicted through reciprocal diagrams. This paper presents a comprehensive review of the development, application, and current state of graphic statics, with particular emphasis on its computational and three-dimensional extensions. Although the fundamentals of graphic statics date back to the 18th century, there has been a resurgence in interest in the field throughout the last three decades, primarily due to improvements in digital modeling and visualization tools. The review is structured into three main sections: the historical evolution of graphic statics and its entry into computational domains; an overview of form-finding methods and their integration into design workflows; and the role of graphic statics as a form-finding method in generating spatial, three-dimensional funicular forms. The paper concludes by identifying key research gaps and arguing for further development of graphic statics as a powerful tool for both architectural exploration and structural optimization.
Curtain wall systems play a key role in the aesthetic of modern buildings, serving as a bridge between architectural look and engineering requirements. This study presents a comparative engineering evaluation of steel and aluminum curtain wall systems using a novel Performance Index (PI) framework. The study integrates qualitative SWOT analysis and parametric analysis to support context-specific material selection for projects with seismic, fire-rated, or sustainability priorities. The PI model quantifies compromise across key criteria such as strength, fire resistance, environmental impact, aesthetics, and cost. Results show that steel excels in structurally demanding and fire-critical applications, while aluminum offers superior corrosion resistance, aesthetic flexibility, and environmental advantages. The extended PI model further demonstrates that aluminum becomes competitive in visually expressive and sustainability-driven designs. Ultimately, this framework empowers engineers and architects to make smarter, context-sensitive decisions when selecting curtain wall materials, balancing safety, sustainability, and design intent.
Mortar has been widely applied as a coating for various purposes on building infrastructures, including basements, water tanks, retaining walls, dams and building exteriors, where resistance to moisture and water is highly required. Various chemicals have been added to mortar to reduce its water permeability. However, they raise environmental problems, therefore, environmentally friendly additives are indispensable. The purpose of this study was to enhance the water resistance, compressive strength, and crack recovery ability of mortar with the addition of hydrochar from biomass. Hydrochar was prepared from the hydrothermal carbonization of coconut coir fiber at 150°C for 4 hours. The hydrochar was added to the mortar at different particle sizes and ratios to cement. Mortars were made by mixing cement, sand, water, superplasticizer, and hydrochar; and they were tested after 28 days. The results showed that the addition of 1 wt% hydrochar with a particle size of 150-250 µm reduced the water permeability of mortar, as evidenced by a 36.45% decrease in secondary water absorption and a 14.94% reduction in percentage of void. In addition, the compressive strength increased by 10.29% compared to the control mixture. Hydrochar can absorb water bubbles in the mortar mixture; however, excessive hydrochar causes the mortar to be more porous. The addition of hydrochar in mortar demonstrated superior crack recovery abilities because it functions as a connection medium to accelerate the recovery.
