Life Cycle Performance Research Articles

Bio-Concrete and Its Self-Healing Capacity to Next-generation Sustainable Architecture: A Comprehensive Review

Concrete is commonly used as a foundation material in the construction sector. It's been around for over two centuries, and it looks like it'll keep being the material of choice for construction for the foreseeable future. Structural materials, long-term degradation creates microcracks which increases permeability and eventually lead to failure. Moreover, the identification and remediation of these fissures provide a formidable challenge, as they jeopardize the integrity and longevity of concrete buildings, particularly those subject to rigorous sealing criteria. Cement manufacturing and widespread usage both contribute to climate imbalance, with the former responsible for 5–7% of global carbon dioxide emissions. Biotechnology provides a viable alternative by allowing the culture of bacteria to produce calcium carbonate, a key ingredient in cement. Biomineralization and crystallization processes play a crucial role in the synthesis and transportation of concrete-compatible chemicals, enabling their delivery to fissure within concrete structures. This review paper discusses a methodology for advancing sustainable architecture in the future, utilizing the adaptable metabolic processes of microorganisms as a foundation. This involves integrating microbial technologies and materials created by microorganisms into the field of built environment design and construction. Currently, there is a growing presence in the market of innovative materials such as Bio-cement, which exhibit lower levels of embodied carbon compared to traditional materials. Furthermore, it discusses advancements in the synthesis and optimization of bio-concrete to address challenges in energy efficiency, structural integrity, and lifecycle performance. By bridging sustainability goals with cutting-edge technology, bio-concrete emerges as a cornerstone for resilient and eco-friendly infrastructure, laying the foundation for innovative architectural paradigms.

Influence of different temperatures and diets on the life cycle of invasive species Conogethes punctiferalis.

Understanding the interactive effects of temperature and diet on insect life cycles is crucial for effective pest management. Here, the influence of different temperatures and diets on the life cycle of Conogethes punctiferalis was investigated using the age-stage, two-sex life table analysis. The results support the hypothesis that temperature and diets (maize, apple, and artificial diet) significantly influence the entire life cycle performance of C. punctiferalis. The duration of larval development was significantly prolonged, whereas adult lifespan was shortened and showed lower reproductive capacity on apple and artificial diet than maize. The total pre-oviposition period was longer on apples than on maize and artificial diet at both temperatures (20, 26°C). The highest r (0.113 d-1), λ (1.128 d-1), R0 (57.213) , and GRR (75.54) of C. punctiferalis were found on maize at 26°C, while the highest T (45.062) was found on apples. Similar results were obtained in the age-specific survival curves (sxj), fecundity (mx), maternity (lxmx), and reproductive value (vxj) of YPM on different host plants when exposed to 20°C. These findings highlight the need for further research into the complex interactions between temperature, diet, and insect life history traits to develop effective pest management strategies and enhance our understanding of insect ecology in agroecosystems.

High Energy Density Batteries for All-Electric Aircraft: Challenges and Technological Innovations

The development of all-electric aircraft has gained significant momentum in the global effort to achieve sustainable aviation. However, a major obstacle remains the challenge of creating high-energy-density batteries capable of meeting the stringent requirements of aviation. As the primary power source, the battery's performance is crucial to the aircraft's range, payload capacity, and overall safety. This paper focuses on the potential impact of various high-energy density battery technologies, such as lithium-ion batteries, nanobatteries, and solid-state batteries, on electric aviation. This work analyzes the advantages and limitations of each technology, highlighting key technical challenges, including thermal management, material efficiency, and lifecycle performance. In addition, the paper examines design considerations specific to aviation, such as weight, energy output, and safety regulations, with insights drawn from recent electric aircraft projects. By reviewing both successes and obstacles in the field, this study aims to offer a roadmap for the future of electric aviation and provide strategic guidance for overcoming the current technological barriers to high-performance batteries in aerospace applications.

The Buckling Behavior and Reliability Evaluation of a Cable-Stayed Bridge with Unique-Shaped Towers.

Buckling is a significant concern for cable-stayed bridges that incorporate a large number of steel components, particularly those featuring unique-shaped towers that require further examination due to the intricate internal force and stress distribution. This paper investigates the buckling behavior of a cable-stayed bridge with inverted V-shaped towers. The cable tower is characterized by its unique design that consists of diagonal bracings and columns in a compression-bending state. A finite element model is established for the nonlinear buckling analysis of the bridge, revealing that the buckling failure mode of the bridge mainly concerns the tower columns that bear large bending moments and axial compressions. The buckling safety factors are analyzed under different loading conditions and design parameters, including the stiffening rib thickness, the width-to-thickness ratio, and the initial cable forces. It indicates that the design optimization can be achieved by using smaller and thinner ribs while maintaining the buckling safety factor above the required level in design specifications. Furthermore, the reliability evaluation of buckling safety is considered using Monte Carlo simulations, which incorporates the long-term effects of corrosion on steel components. Based on the identified buckling failure modes and safety factors, it suggests that the buckling resistance of the bridge is sufficient, though it can be further enhanced by using high-strength weathering steel on critical parts. Additionally, maintenance interventions are shown to be highly beneficial in improving the life-cycle performance of the structure.

Synthesis, and structural characterization of FeMoO4/r-GO nanocomposite as an electrode material for energy storage application

Improving the energy density of electrochemical supercapacitors requires the urgent development of novel electroactive materials. Metal molybdate-based nanostructures are promising candidates as effective electrode materials for the next generation of energy storage solutions. In the present work, a FeMoO4/r-GO nanocomposite was synthesized via the hydrothermal method and used as anode material for supercapacitor application. The structural, and topographical properties were investigated by XRD, FE-SEM, and TEM analysis. Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission electron microscope (TEM) images of FeMoO4/reduced graphene oxide (r-GO) composites show an irregular, rod-like structure coated with r-GO sheets. The FeMoO4/r-GO nanocomposite electrode material exhibited a remarkable specific capacitance of 240 F/g at the current density of 1 A/g, which is significantly higher than the 167 F/g capacitance of pure FeMoO4. The continued charge–discharge (GCD) (5,000) life cycle performance of FeMoO4/r-GO was the retention and coulombic efficiency of 90 % to 86 % after 10 A/g.

Synthesis and characterization of sheets like ZnO/MWCNT nanocomposites as a positive electrode material for asymmetric supercapacitor application

One practical approach to addressing the disparity between global energy needs and availability is through the advancement of effective energy storage systems, such as batteries and supercapacitors. These devices can store excess power and release it when demand surpasses supply, ensuring a stable energy flow. In the present work, the sheet-like ZnO/multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared by a simple hydrothermal method and used as positive electrode materials for supercapacitors. This investigation aims to design an effective electrode material for supercapacitors by harnessing the combined benefits of ZnO nanostructures and MWCNTs. The synergistic interaction between these materials is expected to significantly boost the electrode’s capabilities. The formation, crystal structural, morphological, elemental composition, and energy storage properties of prepared ZnO/MWCNTs electrodes were studied by various analytical methods (XRD, FTIR, TEM, XPS, CV, GCD, and EIS). The electrochemical performances of ZnO/MWCNTs electrode demonstrated specific capacitance (Cs) of 162.2 F/g at the current density of 2 A/g. The life cycle performances of prepared ZnO/MWCNTs electrode exhibited a 94 % after 2000 GCD cycles at 10A/g. The constructed ZnO/MWCNT//AC device attains a peak energy density of 19.50 W h/kg with a corresponding power density of 1280 W/kg.

Sustainability assessment of granite cutting waste incorporated cement sand rendering mortar: Technical, environmental, cost, and social parameters

The literature statistics unmistakably highlight the critical need to enhance the construction industry's sustainability to lower environmental damage and conserve natural resources. This study aims to evaluate the life cycle performance of mortar by assessing its ecological impacts, economic performance, and social feasibility, alongside a thorough technical performance evaluation. The technical performance evaluation performed through physio-mechanical performance revealed that 20% natural sand replaced by granite cutting waste (GCW) is best suitable for rendering application. The compatibility of GCW as natural sand is advocated by SEM and FTIR analysis. The three pillars of sustainability are evaluated as life cycle environmental impacts assessment (LCIA), life cycle cost analysis (LCCA) and social feasibility assessment (SLCA). For LCIA purposes, nine environmental impact (EI) categories have been studied. For LCCA, raw material procurement, transportation, repair, and maintenance have been utilized to obtain the life cycle costing. Social LCA (SLCA) was performed qualitatively through a five-point Likert scale-based questionnaire survey, and responses from 125 stakeholders were analysed using mean item score (MIS). The finding revealed that for GP20 mortar, all the nine EI categories had shown 10–13% lower environmental impacts and 7.2% lower cost than the GP0 mortar mix. The SLCA, comprising five subcategories, i.e., access to material resources, social acceptance, employment creations, safe and healthy living conditions, and community engagement, has positively impacted society when 20% GCW is utilized in rendering mortar as sand. The consolidated index calculation with higher ECM values for the GP20 mortar mix strongly endorsed a sustainable and viable alternative.

Subgrade performance assessment for rigid runway using long-term pavement performance database

Maintaining desired subgrade performance is an effective way to reduce runway pavement deterioration. Due to lack of extensive field test data, life-cycle performance of runway subgrade has not been fully understood. In order to quantitatively estimate subgrade condition, a novel method of evaluating subgrade performance was developed and validated using the 726 sets of Heavy Weight Deflectometer (HWD) test data of ten runway sections. Statistical analysis demonstrates that the structural behaviour of rigid runway subgrade follows normal distribution in different service stages and can be efficiently evaluated by the subgrade performance index (ψ). The results of factor analysis show that Accumulated Air Traffic Volume (ATV) during service life is the major cause of spatial variations in subgrade condition. In the designed service period of runway, it validates that sea-reclaimed subgrade results in faster degradation in the initial stage of service life while thicker pavement exhibits better capability in protecting the subgrade soil in long-term view. Besides, the differences in applied loads and pavement thickness give rise to the subgrade performance variation in longitudinal direction. Meanwhile, the comparison between the main and the less trafficked test lines in transversal direction reveals that the aircraft impacts play a positive role in resisting the natural fatigue process. By the suggested method, subgrade performance of HWD test points can be categorized into 4 levels from “Excellent”, “Good”, “Fair” to “Poor” based on ψ value. It is helpful for airport agency to make scientific decisions on Maintenance and Rehabilitation (M&R) treatment by calculating the effective area of envelope (β) using the ratio of subgrade performance (η).

Comparative Study of Life-Cycle Environmental and Cost Performance of Aluminium Alloy–Concrete Composite Columns

As is widely known, the construction industry is one of the sectors with a large contribution to global carbon emissions. Despite numerous efforts in the construction industry to develop low-carbon materials, there is a limited number of studies quantifying and presenting the overall environmental impact when these materials are applied in a construction project as structural members. To address this gap, this study focuses on assessing the life-cycle performance of novel structural aluminium alloy–concrete composite columns. In this paper, the environmental impacts and economic aspects of a concrete-filled aluminium alloy tubular (CFAT) column and a concrete-filled double-skin aluminium alloy tubular (CFDSAT) column were assessed using life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) approaches, respectively. The cradle-to-grave system boundary is considered for these analyses to cover the entire life-cycle. A concrete-filled steel tubular (CFST) column is also assessed for reference. All columns are designed to have the same load-carrying capacity and, thus, are compared on a level-playing basis. A comparison is also made of the self-weight of these columns. In particular, the self-weight of the CFST column is reduced by around 17% when the steel tube is replaced by an aluminium alloy tube, and decreased by 47% when the double-skin technique is adopted in CFDSAT columns. The LCA results indicate that the CO2 emission of CFST and CFAT is almost the same, which is 21% less than the CFDSAT columns due to the use of high aluminium in the latter. The LCCA results show that the total life-cycle cost of CFAT and CFDSAT columns is around 29% and 14% lower, respectively, than that of the CFST column. Finally, a sensitivity analysis was carried out to evaluate the effects of data and assumptions on the life-cycle performance of the examined columns.

Optimizing plastic waste inclusion in paver blocks: Balancing performance, environmental impact, and cost through LCA and economic analysis

Rising waste plastic and cement used in construction raises environmental concerns. Substituting cement with recycled plastic waste (PW) in paver blocks offers an eco-friendly solution. However, a comprehensive life cycle assessment (LCA) economic and performance analysis is lacking. This study addresses this gap by evaluating the compressive strength and durability properties of PSPB while also conducting LCA and economic evaluations to identify the most optimal solutions for enhanced performance. Compressive strength tests determined that a 30% PW replacement yielded optimal results. The durability tests showed that PW paver blocks have significantly lower water absorption compared to conventional blocks, and they maintained a compressive strength of 20 MPa, which is acceptable for light traffic applications, even at elevated temperatures. LCA highlights that cement usage accounts for over 80% of climate change emissions for conventional blocks. Sensitivity analysis shows shipping distance, truck capacity, and energy use greatly affect environmental outcomes. Complete replacement of cement with PW is considered more environmentally friendly. Economic analysis indicates plastic pavers are 52% more cost-effective than cement-based ones. This research offers vital insights into the practicality, environmental impact, and financial sustainability of integrating PW into paver blocks.

Life-Cycle Performance Modeling for Sustainable and Resilient Structures under Structural Degradation: A Systematic Review

The performance of structures degrades during their service life due to deterioration and extreme events, compromising the social development and economic growth of structure and infrastructure systems. Buildings and bridges play a vital role in the socioeconomic development of the built environment. Hence, it is essential to understand existing tools and methodologies to efficiently model the performance of these structures during their life cycle. In this context, this paper aims to explore the existing literature on the life-cycle performance modeling, assessment, enhancement, and decision making of buildings and bridge infrastructure systems under deterioration and extreme events for a sustainable and resilient built environment. The main objectives are to (1) systematically review the existing literature on life-cycle performance modeling of buildings and bridges based on the PRISMA methodology, (2) provide a bibliometric analysis of the systematically assessed journal articles, (3) perform an analysis of the included articles based on the identified components of life-cycle performance modeling, and (4) provide a discussion on the utilized tools, techniques, methodologies, and frameworks for buildings and bridge infrastructure systems in the life-cycle context. The provided systematic literature review and subsequent discussions could provide an overview to the reader regarding the individual components and existing methodologies of life-cycle performance management under deterioration and extreme events.

A novel life-cycle analysis approach using pavement performance curves with cost and performance considerations

ABSTRACT The life-cycle duration (TLC) is typically assumed constant in pavement life-cycle analysis. The added scientific value of this paper is that (TLC) is considered a variable parameter to be estimated from the performance curve using a variable terminal condition rating. A variable (TLC) requires using the equivalent annual value (EAV) instead of the net present value for cost estimation. The life-cycle performance (LCP) curve is constructed using two routine maintenance cycles separated by one major rehabilitation action. The time parameters associated with LCP curve are estimated from the inverse performance function based on the initial, present and terminal condition ratings. The equivalent annual cost and performance associated with a particular LCP curve are used to compute cost/performance (C/P) ratio for optimal maintenance and rehabilitation (M&R) plan selection. The EAV represents the costs of two routine maintenance cycles and one major rehabilitation action. Sample results obtained from three case studies have indicated the reliability of the proposed LCA approach in yielding optimal M&R plans. At the project-level, the optimal M&R plan associated with 7 m/km terminal IRI value resulted in (0.949) minimal (C/P) value. However, the optimal M&R plan with 3.25 terminal PSI yielded (1.50) minimal (C/P) value.

Optimal design of building envelope towards life cycle performance: Impact of considering dynamic grid emission factors

Building-related carbon emissions in the construction and operation stages account for more than one-third of global energy-related emissions. Optimizing during the early design stage is an effective way to reduce building carbon emissions. However, current studies adopt a constant grid emission factor (GEF) to assess the environmental impacts of buildings while ignoring the dynamic changes of the future electricity mix. This will overestimate the operational carbon emissions of the building in the context of the increasing share of renewable energy in power generation. In this study, a dynamic life cycle assessment model based on dynamic GEF is constructed to evaluate the life cycle environmental impacts of buildings. On this basis, a building optimization design framework considering dynamic GEF is proposed, and the impact of considering future variations of GEF on the optimal design of the building envelope is explored. The study is conducted in three steps. First, dynamically changing GEFs are predicted under the future electricity mix based on scenario analysis. Second, a multi-objective optimization framework is established to minimize the life cycle carbon emissions (LCCE) of the building while optimizing its life cycle costs (LCC) and indoor discomfort hours (IDH). Finally, the proposed optimization framework is applied to a prototype office building in Shanghai, and a comparative analysis is conducted for the optimal schemes between a static and two dynamic scenarios. The result reveals that ignoring future variations will lead to overestimating the operational carbon emissions by 49.0%-64.8%, which in turn will result in an over-insulated design of the envelope (i.e., additional material consumption). In addition, compared to the static scenario, consideration of dynamic GEF results in a 38.7%-51.6% reduction in LCCE, a 5.2%-6.1% reduction in LCC, and a 5.3%-9.5% increase in IDH for the optimal solutions. This research illustrates the importance of considering dynamic GEF in identifying the optimal design parameters and can help decision-makers reasonably choose the optimal schemes during early-stage design.

Assessing the sustainability of modified biosand filters using life cycle assessment, cost and performance factors

Assessing the sustainability of modified biosand filters using life cycle assessment, cost and performance factors

Investigating intrinsic factors in pavement skid resistance deterioration using an integrated tribology model

To investigate the effect of different texture wavelength deterioration on pavement skid resistance, a tire-pavement tribology model was developed through theoretical derivation and numerical simulation, and five asphalt mixture specimens were used for full life-cycle performance analysis. The results show that simulation model can efficiently calculate stress contribution of each asperity on 3D texture, resulting in simulation outcomes closely matched those of the laboratory tests. Two-dimensional (2D) pavement profile and 2D-PSD show apparent consistency in initial and subsequent stages, it correlates with the asphalt film shedding and aggregate crushing during polishing. Intrinsic factors mainly determine skid resistance durability, which is closely related to the percentage of different particle size aggregates and skeletal structure of the asphalt mixture.

Balancing Emerging Risks Considering the Life-Cycle Perspectives of Submerged Floating Tunnels for a Resilient Future Infrastructure

Infrastructure expansion considerably contributes to greenhouse gas emissions causing the critical global issue of climate change. In recent years, submerged floating tunnels (SFTs) have thus been developed as a sustainable and efficient solution for crossing large water bodies instead of resource-demanding superstructures (e.g., cable stayed bridges). This research delves into a comparative analysis of two SFT design alternatives: SFTs with pontoons and SFTs with tethers centered on environmental sustainability and long-term viability. By incorporating life-cycle assessments and quantitative risk analysis methodologies, our study aims to ascertain the optimal SFT design for real-world application. Our study embarks on detailed investigations into SFTs and then gathers data on material quantities and LCA studies, identifying potential hazards and comparing life cycle performance. Our new findings highlight the significant advantage of the SFT with a tethered design, which has a lower dependency on materials, particularly steels, resulting in lower CO2 emissions. Additionally, in terms of risk, the SFT with tethers has a lower risk profile in general, especially in situations, including environmental elements, like rising water levels, potential tsunamis, and storms. This design is a promising solution for sustainable and resilient infrastructure development, coinciding with global objectives to cut down carbon emissions and enrich potential benefits in the face of increasing climatic uncertainties. Not only does this study scrutinize the risk and environmental aspects of both SFT designs, but it also opens the path for future infrastructure projects that emphasize engineering robustness and environmental sustainability.

Life-cycle assessment of hydrogen produced through chemical looping dry reforming of biogas

Chemical looping dry reforming of methane (CLDRM) using perovskites as a catalyst is considered a promising option for producing hydrogen from biogas. In this work, the life-cycle performance of a system compiling a CLDRM unit paired with a water gas shift unit, a pressure swing adsorption unit, and a combined cycle scheme to provide steam and electricity was assessed. The main data needed to reflect the behavior of the reforming reaction was obtained experimentally and implemented in an Aspen Plus® simulation. Inventory data was obtained through process simulation and used to assess the environmental performance of the process in terms of carbon footprint, acidification, freshwater eutrophication, ozone depletion, photochemical ozone formation, and depletion of minerals and metals. Overall, the environmental viability of the production of green hydrogen from biogas was found to be heavily dependent on the biogas leakage in anaerobic digestion plants. The CLDRM system was benchmarked against a conventional DRM implementation for the same feedstock. While the conventional DRM plant environmentally outperformed the perovskite-based CLDRM, the latter might present advantages from an implementation point of view.

Life-cycle performance prediction and interpretation for coastal and marine RC structures: An ensemble learning framework

Long-term exposure to coastal and marine environments accelerates the aging of reinforced concrete (RC) structures, impacting their structural safety and society impact. Traditional assessments of long-term performance deterioration in RC structures involve complex, nonlinear, and time-intensive studies of physical mechanisms. While existing machine learning (ML) methods can assess the lifetime of these structures, they often prioritize data regression over mechanistic interpretation. To enhance the efficiency and interpretability of predicting the life-cycle performance of RC structures, this study introduces a generic framework based on interpretable ensemble learning (EL) methods. The framework predicts life-cycle performance efficiently and accurately, with optimal hyperparameters automatically tuned through Bayesian optimization. Interpretability algorithms clarify the influence of environmental, durability, and mechanical parameters on structural durability and mechanical predictions. Validation employs real-world cases of RC hollow beams in the coastal area of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). The comprehensive model for RC structures integrates actual data on temperature, humidity, and surface chloride content in the GBA, considering diffusion, convection, and binding effects of chloride ions, corrosion non-uniformity, and crack impact on durability estimation. Comparative analysis with existing ML methods underscores the effectiveness of the framework. The findings highlight the dynamic evolution of feature importance rankings throughout the service life, shedding light on the continuous changes in the significance of different factors when predicting mechanical resistance.

Investigation on optimization strategy of IoT operation mode based on blockchain

Under the call of the national scientific and technological power, the research in the field of sensor technology has made rapid progress. Many smart devices integrating various technical heights have entered the homes of ordinary people. Making these smart devices increasingly intelligent has greatly improved people’s lifestyles and even changed their lives. With the development of blockchain technology and the development of 5G communication equipment and applications, the industrial model of Blockchain and the Internet of Things can also become an important guide for the development of the Internet of Things. Therefore, this paper studies the optimization strategy of the IoT operation mode based on Blockchain. The research results have shown that the IoT operation mode based on Blockchain is superior to the traditional IoT operation mode in terms of node energy consumption, life cycle, and flux performance. Under the IoT operation mode of the Blockchain, the node energy consumption is reduced by about 1.19J on average, and the flux performance is increased by about 21 on average. This showed that the IoT operation model based on Blockchain is feasible.

Destabilizing high-capacity high entropy hydrides via earth abundant substitutions: From predictions to experimental validation

The vast chemical space of high entropy alloys (HEAs) makes trial-and-error experimental approaches for materials discovery intractable and often necessitates data-driven and/or first principles computational insights to successfully target materials with desired properties. In the context of materials discovery for hydrogen storage applications, a theoretical prediction-experimental validation approach can vastly accelerate the search for substitution strategies to destabilize high-capacity hydrides based on benchmark HEAs, e.g. TiVNbCr alloys. Here, machine learning predictions, corroborated by density functional theory calculations, predict substantial hydride destabilization with increasing substitution of earth-abundant Fe content in the (TiVNb)75Cr25-xFex system. The as-prepared alloys crystallize in a single-phase bcc lattice for limited Fe content x < 7, while larger Fe content favors the formation of a secondary C14 Laves phase intermetallic. Short range order for alloys with x < 7 can be well described by a random distribution of atoms within the bcc lattice without lattice distortion. Hydrogen absorption experiments performed on selected alloys validate the predicted thermodynamic destabilization of the corresponding fcc hydrides and demonstrate promising lifecycle performance through reversible absorption/desorption. This demonstrates the potential of computationally expedited hydride discovery and points to further opportunities for optimizing bcc alloy ↔ fcc hydrides for practical hydrogen storage applications.