Low-carbon Construction Research Articles

Evolutionary Analysis of Prefabrication Implementation in Construction Projects under Low-Carbon Policies.

In the context of carbon peak and carbon neutral policies, low-carbon construction has been the focus of most countries worldwide. As one of the most effective ways to achieve green construction, many countries have launched low-carbon policies to promote the development of prefabrication. However, the effectiveness and influencing factors of low-carbon policies on prefabrication need to be further verified under the dynamic game between the government and the construction enterprise. Therefore, this study considered subsidy and carbon tax policies and developed an evolutionary game model to promote the development of the prefabricated construction market. The evolutionary stable strategy of the government and construction enterprise under different scenarios was obtained. Subsequently, a numerical analysis was conducted to further investigate the impact of the key factors on the stable strategy. The results showed that an appropriate hybrid policy of subsidies and taxes could positively promote the prefabrication implementation of the construction enterprise. The government should adopt an appropriate policy intensity according to the maturity of the market. This study can provide effective guidance and practical enlightenment for the government to achieve low-carbon, green, and sustainable construction.

Study on Low-Carbon Construction System of Desakota Village-and-Town Communities: Take Zhejiang Province as an Example

In the context of urbanization, desakota villages and towns, which feature mixed land utilization, a diversified industrial structure, and “half-city and half-town”, have gradually come into being and play a big part in impacting the development of towns and villages. As the top-down policy guidance and control play a minor role, and the bottom-up construction runs out of control, various human settlement problems, such as the waste of land resources, low energy efficiency, high carbonization, and disappearing ecological livability, stand out. The core problems confronting China in the next phase concern the rational utilization of village resources and the guidance for and control over the low-carbon development of villages and towns in the future. Based on the demand for the low-carbon development of the human settlements in desakota villages and towns, the analyzed points in this article include the correlation between the carbon emission intensity and the spatial form characteristics and other related elements in Zhejiang Province. The low-carbon construction of the desakota village-and-town communities is transformed into the spatial form structure in order to gain a better understanding of the low-carbon control elements. A correlation evaluation model is established to provide the basis for the optimization and improvement of a low-carbon construction system from multiple dimensions and perspectives, thus providing a theoretical basis and practical guidance for the future low-carbon construction of desakota villages and towns.

FutureBuilt Zero - A simplified dynamic LCA method with requirements for low carbon emissions from buildings

FutureBuilt is a voluntary program for ambitious low-carbon construction projects. To incentivize measures that lead to the lowest climate change impact from all aspects of buildings and according to national Paris agreement pledges, FutureBuilt Zero introduces an ambition level and a novel calculation methodology for net climate change impacts over the life of a building. The ambition level is tightened over time to help Norway achieve its climate goals. A comprehensive simplified calculation method is introduced, which considers how the timing of emissions during the building life affects the contribution to global warming. Both direct and indirect emissions throughout the lifetime are included; energy use in operation and at the construction site, material production and transport of materials to the construction site, and waste management (incineration). In addition, the climate-positive effects of biogenic carbon uptake, carbonation of cement, potential for future reusability, and exported energy are included. This paper presents the criteria, describes the method and the scientific basis as well as the principles and logic behind the choices made.

The Importance of Low-Carbon Landscape Design in Rural Tourism Landscape

Abstract The paper aims to study the importance of low-carbon landscape design based on rural tourism landscape. First of all, after sorting out and researching the relevant reviews of low-carbon landscapes, taking rural landscapes as the research object, a rural landscape planning and design framework based on the perspective of low-carbon construction is proposed. Then, Xiwuli Village is used as an example to carry out the application practice of specific strategies and the carbon emissions before and after the planning and design are calculated and compared. After the low-carbon planning and design of the rural landscape, the net carbon footprint and the total carbon footprint were significantly reduced, confirming the low-carbon effect of the planning and design strategy. Finally, according to the actual situation of the scenic spot, it points out the principles and policy suggestions that must be followed in the development of low-carbon rural tourism. Experiments show that: the net carbon footprint and total carbon footprint are significantly reduced, which proves the actual effect of low-carbon design and the effect of low-carbon planning and design strategy.

Synthesis and Processing Parameter Optimization of Nano-Belite via One-Step Combustion Method

This paper proposes a new chemical combustion method for the synthesis of nano-low-carbon belite cement via a simple one-step process without using any oxidizers, and related mechanisms are briefly introduced. The starting materials used, including micro-silica (silica fume) as a byproduct of the metallurgic industry and CaCO3 powders, are of great abundance, and the processing parameters involved were optimized using a series of systematic experiments based on X-ray diffraction (XRD) and the Rietveld fitting method. Besides, the properties of the synthesized belite cement were characterized by the Brunauer–Emmett–Teller (BET) technique and scanning electron microscopy (SEM). Experimental results revealed that the optimized fuel agent was urea with a dosage of 4.902 times that of the starting materials by mass, and the corresponding holding temperature and time were 1150 °C and 2 h, respectively. In addition, the CaO/(SiO2 + CaO) for the starting materials should be set at 62.5% by mass ratio. BET and SEM results showed that the obtained belite cement had a specific surface area of 11.17 m2/g and a size of around 500 nm or even smaller in spherical shapes, suggesting that this method was successfully implemented. Thus, it can be a promising approach for the synthesis of nano-belite particles as a low-carbon construction material, which could be used more in the near future, such as for low-carbon concrete productions.

Mechanics, hydration phase and pore development of embodied energy and carbon composites based on ultrahigh-volume low-carbon cement with limestone calcined clay

Engineered cement-based composites exhibit excellent deformability, mechanical behavior, fresh performance and durability. However, the traditional cement-based composites incorporating high volume ordinary Portland cement would lead to high carbon footprint. In this study, a new and eco-efficient engineered cement-based composites was designed by incorporating Polypropylene fibers (PPF) and eco-friendly cement with limestone calcined clay (LC3-ECCs). The LC3-ECCs were analyzed and discussed in terms of mechanical properties, microscopic morphology, hydration products and porosity. The study found that the 28-days compressive behavior was above 44.2 MPa, and the flexural strength remained above 4.8 MPa. Because of the formation and gathering of highly polymerized compound products (C-S-H gel, C-A-S-H gel) in the matrix and plenty of ettringite, the bonding effect between PPF and LC3 cementitious matrix is better. Additionally, the LC3-ECCs with 1.5 % volume content of PP fiber showed less porosity beneficial to the mechanical behavior. This study suggests that low-carbon LC3 has the potential to be successfully utilized as the alternative to OPC and is suitable to design sustainable ECCs, and this low-carbon construction product can be also generally applied into some area with the abundant clay sources.

A New Approach to the Viable Ranking of Zero-Carbon Construction Materials with Generalized Fuzzy Information

This paper aims to put forward an integrated decision approach, with generalized fuzzy information for the viable selection of zero- and low-carbon materials for construction. In countries such as India, the construction sector accounts for high pollution levels and high carbon emissions. To restore sustainability and eco-friendliness, the adoption of low-carbon materials for construction is essential and, owing to the multiple attributes associated with the selection, the problem is viewed as a multi-criteria decision-making problem. Earlier studies on material selection have faced certain issues, such as the following: (i) the modeling of uncertainty is an ordeal task; (ii) the flexibility given to experts during preference elicitation is lacking; (iii) the interactions among the criteria are not well captured; and (iv) a consideration of the criteria type is crucial for ranking. To alleviate these issues, the primary objective of this paper was to develop an integrated framework, with decision approaches for material selection in the construction sector that promote sustainability. To this end, generalized fuzzy information (GFI) was adopted as the preference style as it is both flexible and has the ability to model uncertainty from the following three dimensions: membership, non-membership, and hesitancy grades. Furthermore, the CRITIC approach was extended to the GFI context for calculating criteria weights objectively, by effectively capturing criteria interactions. Furthermore, the COPRAS technique was put forward with the GFI rating for ranking zero- and low-carbon construction materials, based on diverse attributes. The usefulness of the framework was demonstrated via a case example from India and the results showed that the design cost, the financial risk, safety, water pollution, and land contamination were the top five criteria, with blended cement, mud bricks, and bamboo as the top three material alternatives for zero- and low-carbon construction. Finally, a sensitivity analysis and a comparison with other methods revealed the theoretical positives of this framework’s robustness and consistency–but it also revealed some limitations of the proposed framework.

Digital Transformation and Rule of Law Based on Peak CO2 Emissions and Carbon Neutrality

The promotion and implementation of carbon neutrality against peaking carbon dioxide emissions urgently need the support of science and technology and the backing provided by a guarantee of rule of law. The proposition, logic, and progression of digital responses to peaking carbon dioxide levels in the search for carbon neutrality are clearly reflected in the current era, employing big data to address the problems of inadequate central–local coordination and interaction, the inadequate application of the rule of law, campaign-style “carbon reduction” promotion, and scientific and technological support in the promotion and implementation of peak carbon dioxide emissions and carbon neutrality. We need to pay attention to the coordination of digital technology, the rule of law response, and the protection of people’s rights. First, in the process of digital carbon dioxide peaking and carbon neutrality, it is necessary to improve the credibility of carbon dioxide peaking and carbon neutrality through the “whole-process trace” and storage mechanism techniques that are made possible by blockchain technology. Second, it is necessary to refine the management of peak carbon dioxide emissions and carbon neutrality through “decentralization” and consensus mechanisms. Third, it is necessary to improve the effectiveness of governance in the management of peak carbon dioxide emissions and carbon neutrality through “non-falsifiability” and collaboration mechanisms. Fourth and finally, the conclusions of this paper are offered. First, from the aspect of smart city construction, it is necessary to promote the coordinated construction of a low-carbon city and smart city and explore the legal ramifications of low-carbon development in urban governance. Second, in corporate governance, we need to build a low-carbon-development digital platform to promote the integration of digital technology and corporate compliance. Third, in terms of global governance, we need to promote the rule of law in cyberspace to address global climate change, the low-carbon development of digital technology, and the low-carbon construction of a cyber society. Fourth, we need to emphasize the rights and obligations of different parties in the implementation mechanism of the rule of law on digital carbon peaks and carbon neutrality.

Study of Shrinkage Compensation and Feasibility of Engineering Applications of Geopolymer Concrete

In recent years, there has been unprecedented development of marine engineering construction in China. One such development has been the introduction of geopolymer (GP) concrete, which differs from portland cement in terms of durability and corrosion resistance in marine environments, and is also a low-carbon construction material. This study developed a low-shrinkage modified GP (MGP) concrete and researched its potential engineering applications . The research prototype was the Xigang seawall in the Guangdong Province of China. The effects of working performance, compressive strength, temperature rise, and strain of the concrete on the construction were assessed. The results showed that the autogenous shrinkage, chemical shrinkage, and drying shrinkage of the MGP paste were significantly lower than those of conventional GP concrete. The mechanism of shrinkage compensation of the MGP paste was discussed from the viewpoint of mesostructure and thermodynamics. The MGP concrete demonstrated smaller temperature rise and less difference between the internal and external temperatures than did portland cement concrete. Therefore, it featured a lower risk of cracking and was found to be more suitable than portland cement concrete for the rapid construction of seawalls.

Carbon emission evaluation model and carbon reduction strategies for newly urbanized areas

China is the world's largest energy consumer and carbon emitter. Cities account for 85% of China's total carbon emissions, making them key areas for implementing carbon reduction policies. In recent years, the construction of newly urbanized areas in China has been increasing. Thus, conducting research on carbon emission evaluation and carbon reduction strategies for these areas is important to help cities deal with climate change. This study sorted carbon emission sources and sinks according to the management of the government as well as formulated an inventory and evaluation model of the carbon emissions of newly urbanized areas. Three cases located in cities of different scales were taken as examples and their emissions were calculated under the current planning mode. The key factors of emissions at each stage of urban development were analyzed. Accordingly, corresponding carbon reduction strategies were proposed for the planning and operation stages and the short-term and long-term targets for the implementation of carbon reduction strategies were formulated. The carbon reduction effect of various strategies was quantified by comparing the emissions before and after the implementation of strategies. The results of this study can support low-carbon construction policies and green ecological development of newly urbanized areas and cities.

Experimental research on mechanical and impact properties of lightweight aggregate fiber shotcrete

Shotcrete is formed by the construction method of spraying and pouring fine stone concrete under a pressure spray gun. With the development of urban green and low-carbon construction, Lightweight Aggregate Fiber Shotcrete (LAFS) has been widely used in roadway mining and railway tunnels. In order to explore the effects of ceramsite, pottery sand, polypropylene fiber and basalt fiber on the static and dynamic mechanical properties of LAFS, the compressive strength, splitting tensile strength, flexural strength, thermal conductivity, water seepage height test under four dosage levels of LAFS were carried out. The grey relational analysis method was used to determine the proportioning range that satisfied the good static performance of LAFS. The macro-mechanisms and micro-mechanisms of the impact resistance of LAFS were revealed through the split Hopkinson pressure bar test and SEM scanning electron microscope test. The results show that the content of ceramsite is the most important factor affecting the proportion of the range of each evaluation index of LAFS. The proportion of the range of LAFS's compression resistance, splitting tensile strength, flexural strength, thermal conductivity, and water penetration height range are 38.77%, 43.50%, 51.55%, 44.31%, and 59.04%, respectively. The basalt fiber and polypropylene fiber with different physical properties show good rigidity and ductility during the impact test. While the peak stress of the hybrid fiber LAFS is increases, the impact plasticity becomes obvious.

Effect of Austenite Grain Size on the Bainitic Transformation in a 690 MPa Grade High-Strength Multi-Functional Construction Steel

A high-strength low-carbon construction structural steel was investigated in the laboratory. The various austenite grain sizes were obtained by austenitizing the steel at different temperatures. The effect of austenite grain size on bainite transformation was studied by the dilatometer. The results show that the microstructure of high-strength low-carbon structural steels mainly includes granular bainite, lath-like bainite and martensite-austenite (M-A). The microstructure changes from granular bainite to lath-like bainite with the increase in austenitizing temperature or austenite grain size. When the samples were heated at the lower temperature of 860 °C, the bainite starting temperature was relatively high, which was mainly attributed to the promotion of the granular bainitic nucleation and the formation of the solute-depleted regions in the austenite. Compared to 860 and 1260 °C, the bainite transformation rate in the specimen austenitized at 1000 °C is the highest because of the small prior austenite grain size and larger transformation driving force.

Decoupling analysis of carbon emissions in China's power industry-based on ARDL model.

Electric power industry, as one of the main industries leading to the increase of China's carbon emissions, accounts for about 40% of the total carbon emissions. It is of great practical significance to study the influencing factors of carbon emission decoupling index in power industry and put forward relevant policy suggestions. Based on the decoupling index of China's electric power industry from 1995 to 2018, this paper explores the influence of each index on the decoupling index through the autoregressive- distributed lag model. It turns out that the policy will significantly change the rate of change of carbon emissions and the rate of economic growth, but the impact of the policy is extremely short-lived; power generation structure, environmental regulations, and total lighting value at night play a positive role in promoting the decoupling index, while thermal power fuel efficiency and power generation conversion ratio play a negative role in inhibiting the decoupling index. In addition, the influence of power generation structure, environmental regulations, and the total value of night light on decoupling index also has a lagging and cumulative effect. Therefore, we propose targeted policy recommendations for policy formulation, green development, and low carbon construction in China's power industry from different perspectives based on the findings of the study.

A framework for specifying low-carbon construction materials in government procurement: A case study for concrete in a new building investment

There are numerous strategies that can be used to reduce the embodied carbon footprint of real property investments, many of which can be accomplished for no additional cost and with minimal performance impacts. This study aims to propose the incorporation of the life cycle carbon quantification into the government procurement of real property process in order to reach out to low-carbon durable and sustainable structures as a theoretical contribution. As a practical contribution, an integrated embodied carbon measurement application is developed in a building information model (BIM) environment to act as a decision making tool in a government office building as a case study. It supports updating procurement policies and procedures to request construction materials with lower embodied carbon in construction. Analysis of concrete assembly groups in the case study along with determination of volume of concrete in each assembly is conducted to devise a reasonable list of elements to be considered for low-carbon concrete compliancy based on an industry average benchmarking approach. Considering the numerous concrete vendors that supply concrete products to a given region, a novel concrete embodied carbon measurement approach is proposed where cradle-to-construction impacts were accounted for. The outcome of the proposed integrated tool showed the procurement of concrete mix design from one specific nearby facility resulted in more efficient GHG reductions and the results showed especially the significance of considering transportation impacts of delivering ready-mixed concrete elements to the project site.

Strategies and way forward of low carbon construction in Malaysia

ABSTRACT The need for a paradigm shift to achieve low carbon construction is becoming increasingly apparent. Nonetheless, most existing publications have focused on lowering emissions during the operational phase of buildings, emphasizing the need for improved emissions management during construction. Thus, this study aims to investigate industry behaviours and practices and recommend strategies to improve low carbon in construction. The triangulation of information in this study was supported by observations of eight construction sites, expert interviews and responses from 79 respondents involved in construction projects. The findings suggest that limited investment and budget, resistance to change, lack of knowledge and experience on low-carbon technologies are the key impediments to effective carbon reduction strategies. The main determinants of behavioural change and industrial commitment to low carbon practices are boosting financial and economic value, strengthening institutional capacity development, establishing credible policy, promoting awareness, and expanding resources and skills. The findings of this paper may benefit construction stakeholders in identifying specific hurdles to low-carbon implementation and developing appropriate strategies to promote low-carbon development in Malaysia. This research contributes to the current knowledge about the industry’s behaviour and practice in emissions management and the significant challenges and drivers connected with low-carbon growth in developing countries.

Research Progress in Corrosion Mechanism of Reinforced Alkali-Activated Concrete Structures

In this paper, the recent research progress on the corrosion of reinforced alkali-activated materials (AAMs) concrete structures is reviewed. The corrosion mechanisms induced by carbonation and chloride ingress in AAMs concrete are discussed, from the perspectives of composition, microstructure and pore solution chemistry, in comparison to ordinary Portland cement (OPC) concrete. The steel–alkali-activated concrete interface is a key to investigating corrosion initiation and propagation, which has different physical and chemical characteristics of the steel–concrete interface in OPC concrete. Moreover, the electrochemical process testing methods including half-cell potential and linear polarization resistance are critically discussed with a focus on what could be inherited from the OPC concrete and what criteria are no longer suitable for AAMs concrete due to underestimation in most cases. New data and theories are urgently needed for using AAMs in concrete structures to replace OPC. At the end of this paper, the research gaps and future research needs are summarised for the sake of widespread application of AAMs in concrete structures for sustainable and low-carbon construction.

Sustainability Transition through Dynamics of Circular Construction Projects

The aim of this paper is to better understand the dynamics of circular construction projects and how these interorganizational projects contribute to the transition towards a circular economy. It is essential that the construction sector develops and adopts interorganizational initiatives to support the transition to a circular and low-carbon construction economy. A benefit of being involved in such initiatives is that organizations reflect on the emergence and acceptance of new practices related to changing organizational roles and responsibilities. In this paper, we study eight circular construction projects within the context of an interorganizational initiative to stimulate the transition towards a circular economy by exploring insights from evaluations thereof. We build upon literature from Sustainability Transitions Research (STR), circular construction research, and interorganizational project studies. Our findings show three clusters of dynamics that are relevant in the realization of circular ambitions in interorganizational construction projects: (1) prerequisites, (2) temporal dynamics in interorganizational projects, and (3) contextual influences. These insights highlight factors that enable the realization of circular ambitions in construction projects and contribute to our understanding of the dynamics of interorganizational construction projects and their role in the context of STR.

The Framework of Technical Evaluation Indicators for Constructing Low-Carbon Communities in China

In recent years, in order to promote the construction of low-carbon communities (LCCs) in China, many scholars have proposed an evaluation indicator system of LCC. The existing indicator systems are mostly established from the macro perspective of environmental impact and resource conservation, but few are from the micro technical perspective. Thus, the aim of this study is to construct a micro technical evaluation indicator system for LCCs. Firstly, the index system was divided into three categories: low-carbon building, low-carbon transportation, and low-carbon environment. Then, the technical indicators were selected through empirical analysis. The indicator weights were assigned by the improved analytic hierarchy process (AHP) and the multi-level fuzzy comprehensive evaluation method was used as the evaluation method of the indicators. Finally, in order to examine the practicality of the indicator system, two typical communities in Tianjin and Shanghai were selected as case studies. The results showed that the indicator system gave a reasonable low-carbon level for the two communities, which was in line with the actual low-carbon construction status of each community. In addition, the evaluation results pointed out that the low-carbon community (LCC) in Tianjin needs to further strengthen the construction of the low-carbon environment, including community compactness, rainwater collection and utilization, and waste recycling. For the LCC in Shanghai, it was pointed out that the construction of the low-carbon building and low-carbon transportation needs to be strengthened. The indicator system can be used as a tool for urban planning and construction personnel to evaluate the construction progress and low-carbon degree of LCC.

Developing carbon-neutral construction materials using wastes as carbon sink

Developing ecofriendly and low-carbon construction materials is essential to meet the ambitious target of global net zero emission by 2050. The concept of using wastes as carbon sink is taking advantage of alkaline solid wastes, which are rich in calcium or magnesium as a medium for absorbing carbon dioxide (CO2), and allowing manufacturing thermodynamically stable carbonate minerals for construction applications. Today, the major practical and successful applications of CO2 in the construction industry are through accelerated carbonation of granulated aggregates and precast concrete blocks manufactured with different proportions of calcium-rich waste materials. CO2 is also used as an activator in speciality nonhydraulic carbonate-binders or directly injected (in a liquid form) into fresh ready-mix concrete to produce a construction material with higher strength and lower carbon footprint. In addition, accelerated carbonation has become a promising approach to improve the quality of crushed concrete waste, and can be reused in new concrete to attain a sustainable concrete life cycle. In this paper, the progress in academic research of using CO2 in wastes and cement-based products as well as the key advantages and limitations related to the large scale application in the construction industry have been discussed in detail.

Reducing the carbon footprint of buildings to improve sustainable development mechanisms of the construction complex

The construction industry’s impact on the environment is overwhelming. Construction and industrial activities account for about 40 % of the global energy consumption that translates into about one third of global greenhouse gas emissions. The rapid growth of property development and attention to global climate change make the reduction of greenhouse gas emissions a promising area of research. The importance of the carbon impact assessment throughout the life cycle of buildings implies the improvement of emission reduction methods associated with the production and transportation of building materials, selection of optimal design solutions. Evaluation becomes key to the economic modeling of green low-carbon construction. The article addresses the current methods of the eco-economic assessment of the carbon impact of residential buildings at early stages of construction projects. Key construction resources, critically affecting the eco-performance of buildings, are identified. The comparative analysis of functionally equivalent design solutions for mid-rise residential apartment buildings, designed and constructed in the Belgorod region, is carried out. The study shows that the introduction of low-carbon principles into the design of residential buildings should and can be supported by the improved eco-economic evaluation of the construction project efficiency. This allows to capitalize the carbon impact of residential buildings and stimulate the use of effective green low-carbon motivation tools in the building market.