A bi-level optimization approach for sustainable development and carbon emissions reduction towards construction materials industry: a case study from China

The construction and building environment is one of the largest contributors to climate change, greenhouse gas emissions, depletion of natural resources and damage to ecological integrity. Therefore, the use of more sustainable materials in construction is currently of great interest. Structural wood is considered as a versatile renewable material, having an optimal strength-to-weight ratio, insulating properties, low carbon emissions in the operational life cycle and a great abundance in nature. Furthermore, unlike other materials, wood is the only one that stores carbon in its production. The purpose of this project is to evaluate, through the Life Cycle Analysis methodology, the environmental impact of the construction of buildings made of timber compared to reinforced concrete buildings, understanding the environmental benefits and disadvantages of each technology. The results obtained from the comparison of a timber building with its concrete counterpart confirm the feasible benefit of wood in the reduction of carbon emissions and non-renewable energy consumption, as well as other positive aspects such as the reduction of other emissions. By highlighting the benefits and opportunities of wood it is intended to promote the material in construction and the development of more efficient buildings.

The aim of this article is to identify and estimate different inventories of emissions during construction activities. A unique approach for simulating construction materials and their stochastic embodied greenhouse gas (GHG) emissions is proposed. The % of carbon released by various equipment and materials with respect to construction activities was also measured to assess emissions inventory supported by construction project case example. Finding shows that the gross carbon emissions from construction materials was 5419.576 ton of CO2 whereas carbon emissions from sustainable construction materials was 752.383 ton of CO2. The findings of the study, which revealed a significant potential for an 86.19% reduction in carbon emissions by utilizing substitute substances in construction materials compared to conventional materials, have led to the proposal of important measures. These measures are crucial for identifying the primary sources of carbon emissions in construction activity and play a pivotal role in promoting sustainable construction practices and achieving green ratings for construction projects. The research will help sustainable construction & will pave the way for achieving an effective green rating for construction projects.

Aggregates are the second-most consumed product in the world after water. This geological resource is used as building and construction material, and its production in quarries and delivery to customers generates several environmental problems. Their transport from quarries to consumption points, almost entirely done by truck, also generates impacts such as an increase in traffic and noise and the emission of greenhouse gases and other pollutants. Transportation and storage of goods account for 15% of greenhouse gas emissions in Europe and will increase significantly by 2050. To mitigate this, the European Union suggested shifting 30% of long-distance road freight to cleaner alternatives, such as rail or waterborne transport. This approach neglects the enormous volume of short-distance freight movement and its impact on achieving the goal of reducing greenhouse gas emissions. In this study, the hypothesis to test is whether the use of an intermodal rail/road transport mode, instead of just roads, for the transport of some products can help reduce global CO2 emissions even for short distances. To test this, this study investigates the carbon emissions (and transport cost reduction) generated by rail/road intermodal aggregate transport for short distances in the Madrid region (Spain), rather than the currently used direct truck transport. An analysis of variables, such as aggregate supply, demand locations and amounts, and road and rail networks, using a geographical information system provides the associated carbon emissions of the different transport alternatives. To obtain a reduction in CO2 emissions, this study proposes the establishment of intermodal transfer facilities near consumption centers, where materials are primarily transported by rail, with road transport limited to the final delivery to consumption areas. The results anticipate a notable decrease in carbon emissions in aggregate transport and allow the establishment of more efficient and environmentally friendly rail/road intermodal transport that would help to meet the goals of reducing climate change while making the use of aggregates more environmentally friendly.

Transportation is an important source of carbon emissions in China. Reduction in carbon emissions in the transportation sector plays a key role in the success of China’s energy conservation and emissions reduction. This paper, for the first time, analyzes the drivers of carbon emissions in China’s transportation sector from 2000 to 2015 using the Generalized Divisia Index Method (GDIM). Based on this analysis, we use the improved Tapio model to estimate the decoupling elasticity between the development of China’s transportation industry and carbon emissions. The results show that: (1) the added value of transportation, energy consumption and per capita carbon emissions in transportation have always been major contributors to China’s carbon emissions from transportation. Energy carbon emission intensity is a key factor in reducing carbon emissions in transportation. The carbon intensity of the added value and the energy intensity have a continuous effect on carbon emissions in transportation; (2) compared with the increasing factors, the decreasing factors have a limited effect on inhibiting the increase in carbon emissions in China’s transportation industry; (3) compared with the total carbon emissions decoupling state, the per capita decoupling state can more accurately reflect the relationship between transportation and carbon emissions in China. The state of decoupling between the development of the transportation industry and carbon emissions in China is relatively poor, with a worsening trend after a short period of improvement; (4) the decoupling of transportation and carbon emissions has made energy-saving elasticity more important than the per capita emissions reduction elasticity effect. Based on the conclusions of this study, this paper puts forward some policy suggestions for reducing carbon emissions in the transportation industry.

Transportation carbon emission reduction potential and mitigation strategy in China

The construction industry, a major player in economic development, is facing increased pressure to address sustainability concerns amidst rapid population growth and urbanization. With global projections indicating a significant rise in building demand by 2050, sustainability has emerged as a crucial focus area and paradigm shift to enhance environmental friendliness, quality, and project outcomes. The UAE, renowned for its vibrant construction industry, offers a unique context for examining the integration of sustainable practices. The use of sustainable construction practices is growing in the UAE, where the built environment plays a key role in economic growth and environmental stewardship. The United Arab Emirates (UAE) aims to foster long-term sustainability while enhancing the standard of living for current and future generations by integrating social, environmental, and economic aspects within construction projects, while also reevaluating conventional sustainable development frameworks and embracing a triple bottom line approach. This research was conducted to explore sustainable construction material usage and evaluation in the United Arab Emirates. The literature was reviewed for sustainable building construction materials across the UAE in the SCOPUS index from 2014 to 2024, as well as the regional regulations concerning the subject. This study evaluated the increasing trend of sustainable construction material research works, as well as the sound regional parameters of sustainable construction materials implemented across the country. Through an exploration of the significance of sustainable construction materials, this research underscores the multifaceted benefits of locally sourced, recyclable, and renewable materials in reducing environmental impacts, fostering economic and social well-being, and improving overall project performance and project management practices. The construction sector’s role in economic development and its substantial environmental impact are discussed in alignment with sustainable construction materials, sustainable construction practices, and the need to enhance environmental sustainability and create healthier built environments. In the realm of sustainable construction materials, project management knowledge areas encompass a range of factors. These include the properties of materials sourced regionally; the incorporation of recycled content; considerations for indoor air quality, energy, and water efficiency parameters; and how these properties relate to project scopes, scheduling constraints, and challenges. Additionally, the availability of resources and competency levels, quality control standards, specifications, communication strategies, and stakeholder involvement play crucial roles. It is important to assess both the positive and negative risks associated with these elements across construction projects.

<sec><title>Objective</title> The world is still in a phase of rapid industrialization and urbanization. Excessive carbon emissions has become the primary root cause of various urban or even global environmental problems, further impacting human physiological and psychological health. Cities are the largest sources of carbon emissions and are crucial regions for achieving carbon neutrality goals. Urban blue-green infrastructure (UBGI), comprising natural, semi-natural, or artificial green and blue spaces within cities, is considered as the most important carbon sink space in urban areas and has increasingly attracted widespread attention from researchers. However, there are still many unresolved issues regarding the effectiveness of UBGI in carbon sink enhancement and emission reduction: 1) How is the energy efficiency of carbon sink enhancement and emission reduction measured, and what factors influence it? 2) What are the mechanisms and pathways through which UBGI enhances carbon sink and reduces carbon emission? 3) How can UBGI be regulated to better enhance its effectiveness in carbon sink enhancement and emission reduction? 4) What are the limitations and potential directions for future research? This research aims to address these issues and propose scientifically sound planning strategies for UBGI construction to achieve urban carbon neutrality goals. </sec><sec><title>Methods</title> Through literature synthesis and deduction, this research organizes and analyzes the multi-scale measurement methods for UBGI’s efficiency in carbon sink enhancement and emission reduction, identifies corresponding influencing factors at each scale, and constructs multi-scale planning strategies for UBGI based on the logical framework of “measurement methods–influencing factors – planning strategies”. </sec><sec><title>Results</title> The research proposes UBGI planning strategies across three spatial scales (site, community and urban area), covering three key aspects: Carbon sequestration and sink enhancement, carbon reduction based on temperature reduction (or preservation), and travel-related carbon reduction. Based on current research gaps and planning needs, five major research topics are further identified. This research provides a detailed analysis of the measurement methods and influencing factors of UBGI’s efficiency in carbon sink enhancement and emission reduction from three perspectives: Carbon sequestration and sink enhancement, carbon reduction based on temperature reduction (or preservation), and travel-related carbon reduction. The research finds significant differences in the measurement methods for UBGI’s efficiency in carbon sink enhancement and emission reduction efficiency across different scales. Contradictory results may occur at different scales, and large-scale research often lacks characterization of internal features, leading to unclear mechanisms of influencing factors and obstructing practical planning. Based on the interpretation of UBGI’s mechanisms for carbon sink enhancement and emission reduction at different scales, this research formulates UBGI planning strategies across three spatial scales (site, community, and urban area). These strategies include: 1) At the site scale, for carbon sequestration and sink enhancement – carbon sink at the source, land balance, and ecological design; for emission reduction – symbiosis with buildings and integration into daily life. 2) At the community scale, for carbon sequestration – overall balance of revenue and expenditure, precise positioning, and proper interconnection of the carbon chain; for emission reduction – incorporation of cool islands and co-construction. 3) At the urban area scale, for carbon sequestration – enhancement of ecological space management and establishment of a carbon-safe pattern; for emission reduction – demand-based layout and organic dispersion. Finally, the research proposes five major research topics for the planning of UBGI’s carbon sink enhancement and emission reduction: How to construct unified measurement methods for UBGI’s efficiency in carbon sink enhancement and emission reduction across scales? How to measure UBGI’s efficiency in carbon reduction based on temperature reduction (or preservation) at the site scale? How to integrate the pathways of carbon sink enhancement and emission reduction for a life cycle assessment of UBGI? How to balance UBGI’s carbon sink enhancement and emission reduction with other functions to achieve the optimal layout for comprehensive benefits? How to achieve urban “carbon justice” through UBGI? </sec><sec><title>Conclusion</title> The carbon sink pathway of the strategy framework requires “carbon sink at the source – precise positioning – safe pattern”, and the emission reduction pathway requires “symbiotic integration – co-construction and sharing – organic dispersion”. The key trade-offs between these two pathways at three spatial scales may provide theoretical support and practical guidance for UBGI construction and management. The five major research topics mentioned above may offer valuable assistance for UBGI construction and future research. </sec>

Carbon peaking in the transportation sector has become an important step toward achieving the double carbon goals. Based on the causal relationship among the elements of the transportation carbon emission system, a system dynamics model was constructed from four aspects: economy, population, transportation, and carbon emission. In addition, baseline, single, low-carbon, and enhanced low-carbon scenarios were set up to analyze the change trend of transportation carbon emissions in China and the transportation carbon emission reduction potential from 2021 to 2035, and corresponding suggestions were presented. The results showed that: ① Under the baseline scenario, transportation carbon emissions increased rapidly, reaching 1.388 billion tons in 2035, with an average annual growth rate of 2.32%, and the peak of transportation carbon was not achieved. ② Under the single scenario, the enhanced freight- and industrial-structure scenarios had the best emission reduction effect, with the carbon emission reduction rate in 2035 reaching 124 and 67 million tons, respectively, and the emission reduction rate reached 8.93% and 4.85%, respectively. ③ Under the low-carbon scenario, the average annual growth rate of transportation carbon emissions from 2021 to 2030 was 1.77%, and the growth rate was expected to gradually slow down after 2030, with emission reduction measures beginning to show effects. By 2035, transportation carbon emissions were projected to reach 1.196 billion tons, but the peak in transportation carbon was still not reached. ④ Under the enhanced low-carbon scenario, through more powerful emission reduction measures such as optimizing the transportation structure and industrial structure and improving the level of transportation technology, transportation carbon emissions were projected to peak in 2033, with a peak value of 1.130 billion tons. By 2035, the emission reduction rate could reach 18.94%, among which the road carbon emission reduction rate would be 26.48% under the enhanced low-carbon scenario. This is an important breakthrough for transportation carbon emission reduction. Therefore, suggestions were presented to optimize the transportation structure, improve the transportation infrastructure, promote the upgrading of industrial structure, and strengthen the research and development of transportation equipment technology.

ABSTRACTThis study investigates the viability and benefits of utilizing compressed earth blocks (CEBs) as a sustainable construction material under varying climatic conditions, focusing on two cities in Saudi Arabia: Riyadh, representing a hot desert climate, and Abha, representing a cooler, high‐altitude climate. A comprehensive simulation‐based methodology was employed, which included energy performance modeling and optimization using EnergyPlus software, climate data analysis, environmental impact assessment, and cost analysis. To further verify the results, the EnergyPlus simulations were validated using a machine learning model, specifically the gradient boosting regressor (GBR), to ensure accuracy and reliability. The simulations demonstrate that CEBs provide substantial benefits in terms of structural performance, energy efficiency, and sustainability. For instance, CEB buildings showed reduced cooling loads by 35% in Riyadh and 25% in Abha, while also maintaining high indoor air quality and thermal comfort, leading to 80‐85% occupant satisfaction. The use of CEBs contributed to significant reductions in carbon emissions, with 90% renewable materials, and proved to be cost‐effective over the long term. The GBR validation confirmed less than 2% variation from the EnergyPlus simulations, further ensuring the reliability of the results. Environmental impact assessments revealed substantial reductions in carbon emissions, resource consumption, and waste generation through the adoption of CEBs. Although the initial cost of CEBs may be slightly higher than traditional materials, the long‐term energy savings and reduced maintenance costs make them an economically viable option, particularly in regions with extreme climates. This study underscores the potential of CEBs as a versatile, efficient, and sustainable building material, offering significant benefits in energy efficiency, environmental impact reduction, cost‐effectiveness, and occupant comfort—all based on robust simulation and modeling results.

The Hu-Bao-O-Yu urban agglomeration is an important energy exporting and high-end chemical base in China, and is an important source of carbon emissions in China. The early achievement of peak carbon emissions in this region is particularly crucial to achieving the national carbon emission reduction targets. However, there is a lack of multi-factor system dynamics analysis of resource-dependent urban agglomerations in Northwest China, as most studies have focused on single or static aspects of developed urban agglomerations. This paper analyses the relationship between carbon emissions and their influencing factors, constructs a carbon emission system dynamics model for the Hu-Bao-O-Yu urban agglomeration, and sets up different single regulation and comprehensive regulation scenarios to simulate and predict the carbon peak time, peak value, and emission reduction potential of each city and urban agglomeration under different scenarios. The results show that: (1) Hohhot and Baotou are expected to reach peak carbon by 2033 and 2031 respectively, under the baseline scenario, while other regions and the urban agglomeration will not be able to reach peak carbon by 2035. (2) Under single regulation scenarios, the effect of factors other than the energy consumption varies across cities, but the energy consumption and environmental protection input are the main factors affecting carbon emissions in the urban agglomeration. (3) A combination of the economic growth, industrial structure, energy policy, environmental protection, and technology investment is the best measure to achieve carbon peaking and enhance the carbon emission reduction in each region as soon as possible. In the future, we need to coordinate the economic development, energy structure optimisation and transformation, low-carbon transformation of industry, strengthen research on carbon sequestration technology, and further increase the investment in environmental protection to make the Hu-Bao-O-Yu urban agglomeration a resource-saving urban agglomeration with an optimal emission reduction.

Regional transportation emissions reduction is the key to realizing deep emission reduction and the neutralization of transportation. Transportation development is accompanied by technological progress, and inter-regional transportation technological progress and carbon emission spillover effects are issues worthy of study. Based on the 2011–2020 provincial data of 30 provinces and cities in China, a spatial Durbin model was constructed to explore the impact of technological progress on regional spillovers of carbon emissions and the driving effect of emissions reduction. The conclusions show that the “community effect” causes direct interactions between transportation carbon emissions reduction practices in various provinces; the “acquired effect” and “leakage effect” drive technological progress between regions and cause indirect interactions between transportation carbon emissions reduction practices; transportation technology progress is more likely to occur between regions with similar transportation development. Finally, some suggestions are put forward in terms of establishing a mechanism for the coordinated reduction of regional carbon emissions, strengthening the interactions and economic connections between inter-regional transportation technologies, optimizing the spatial layout of transportation infrastructure, and building a low-carbon transportation system, so as to lay a solid foundation for the coordinated reduction of regional transportation carbon emissions.

bamboo is a construction material with excellent mechanical and thermal properties. It also has excellent carbon storage capacity and is already widely recognized as a sustainable construction material. This study quantifies the bamboo’s potential for energy efficiency and carbon emission reduction throughout the building life cycle in the cold and severe cold regions of China. A six-storey residential building is applied as a case study for a comparison between reinforced concrete (RC) and laminated bamboo lumber (LBL) construction in five representative cities. The comparison considers the inventory analysis of the materialization, operation, and end-of-life (EoL) stage, energy consumption as simulated by the commercial software IES-VE, and carbon emissions assessed by a process-based method. The results for the five cities show that the use of bamboo instead of the conventional reinforced concrete structure would reduce energy consumption by 3%∼5% and reduce CO2 emissions by 7%∼20%. The analyse of results demonstrates that bamboo residential buildings are more carbon-efficient in cold climates. Furthermore, this study clarifies the applicability and sustainability of bamboo construction materials and contributes to suggesting alternatives for the life cycle carbon reduction for residential buildings.

Fiber-reinforced mycelium (FRM) composites offer an innovative and sustainable approach to construction materials for architectural structures. Mycelium, the root structure of fungi, can be combined with various natural fibers (NF) to create a strong and lightweight material with environmental benefits. Incorporating NF like hemp, jute, or bamboo into the mycelium matrix enhances mechanical properties. This combination results in a composite that boasts enhanced strength, flexibility, and durability. Natural FRM composites offer sustainability through the utilization of agricultural waste, reducing the carbon footprint compared to conventional construction materials. Additionally, the lightweight yet strong nature of the resulting material makes it versatile for various construction applications, while its inherent insulation properties contribute to improved energy efficiency in buildings. Developing and adopting natural FRM composites showcases a promising step towards sustainable and eco-friendly construction materials. Ongoing research and collaboration between scientists, engineers, and the construction industry will likely lead to further improvements and expanded applications. This article provides a comprehensive analysis of the current research and applications of natural FRM composites for innovative and sustainable construction materials. Additionally, the paper reviews the mechanical properties and potential impacts of these natural FRM composites in the context of sustainable architectural construction practices. Recently, the applicability of mycelium-based materials has extended beyond their original domains of biology and mycology to architecture.

Faced with increasingly strict carbon emission control, high-emission enterprises need scientific and rational management systems and methods to strengthen carbon emission reduction management. Among the many management systems and methods, the carbon budget has become an effective emission reduction management tool, allowing the planning of carbon emissions and emission reduction activities and rational arrangement of economic inputs. However, judging from the research status and business practices in China and abroad, there is no general carbon budget system to guide the development of carbon emission and emission reduction activities. Based on this background, this paper first attempts to construct an enterprise carbon budget system comprising four sub-budgets: carbon emission, carbon emission reduction and cost, carbon emission rights trading, and carbon emission reduction net profit/loss. It draws on the idea of interactive control to consider the impact of changes in carbon prices, energy prices, and policy guidelines on carbon emission reductions and losses. A carbon budget management system based on interactive control is then constructed and applied to China National Aviation Holding Air China Group (AC Aviation). The research results show that the carbon budget system based on interactive control can dynamically adjust carbon emission reduction behavior based on changes in carbon and energy prices to make carbon budgeting a more viable carbon reduction tool and institutional arrangement.

The carbon emissions of the beer industry have always been a concern. To reduce environmental pollution, this paper systematically calculates the carbon emissions of the beer supply chain and studies the optimization of carbon emissions reduction through scenario simulation. In this study, the boundary of the beer supply chain carbon emissions system is constructed. The scenario simulation and simulation analysis are carried out based on five factors: water recycling utilization rate, power generation mode, weight-volume ratio, recovery ratio, and transportation mode. To obtain the optimal scheme of economic cost and emissions reduction, the cost of the beer supply chain is analyzed under the condition of carbon trading. The results show that the proportion of carbon emissions in each link of the beer supply chain is production, packaging, transportation, and storage, which are 59.58%, 22.27%, 17.67%, and 0.5%, respectively. The improvement of the water recycling utilization rate of manufacturing enterprises can reduce the overall carbon emissions of the supply chain, and the effect is obvious. The highest proportion of carbon emissions in the packaging link is the bottle consumption stage (22.43%). Raw materials transportation accounts for the highest proportion of total carbon emissions in transportation (63.73%). The waterway/railway ratio will be increased to 0.6/0.4, and the carbon emissions in the supply chain will be reduced by 5.7%. In the context of carbon trading, when the carbon trading price is higher than 49.16 yuan/ton, enterprises can achieve a win-win situation in reducing emissions and maintaining positive economic growth by the measures given in the paper.