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The fragmented nature of construction operations makes it challenging to implement carbon-reduction strategies. However, attaining a holistic construction sector decarbonisation hinges upon ensuring all aspects of a construction project's lifecycle are decarbonised, including the construction process stage. Therefore, to mitigate the implementation challenge of reducing the levels of carbon involved in construction processes, this study attempts to synthesise and categorise carbon-reduction strategies that could be employed to decrease the carbon footprint during a construction projects' delivery. To achieve the aim of this study, a systematic literature review approach was adopted. Based on this technique, a total of 26 relevant articles within the built environment research area were eligible for the study, and their analysis revealed 56 carbon minimisation measures, which were summarised into nine distinct categories to ease their application and overcome the construction operations' complexities. The nine categories include material transport, waste transport, materials and equipment, waste, materials, on-site office, on-site lighting, on-site transportation of material and equipment, and construction methods. The findings of this study provide contractors with a suite of measures that can be deployed to reduce the carbon impact of construction project delivery. [ABSTRACT FROM AUTHOR]

With the development of the engineering construction industry, knowledge became an important strategic resource for construction enterprises, and knowledge graphs are an effective method for knowledge management. In the context of peak carbon dioxide emissions and carbon neutrality, low carbon emission became one of the important indicators for the selection of construction schemes, and knowledge management research related to low carbon construction must be performed. This study investigated a method of incorporating low-carbon construction knowledge into the bridge construction scheme knowledge graph construction process and proposed a bridge construction scheme recommendation method that considers carbon emission constraints based on the knowledge graph and similarity calculation. First, to solve the problem of the poor fitting effect of model parameters caused by less annotation of the corpus in the bridge construction field, an improved entity recognition model was proposed for low-resource conditions with limited data. A knowledge graph of low carbon construction schemes for bridges was constructed using a small sample dataset. Then, based on the construction of this knowledge graph, the entities and relationships related to construction schemes were obtained, and the comprehensive similarity of bridge construction schemes was calculated by combining the similarity calculation principle to realize the recommendation of bridge construction schemes under different constraints. Experiments on the constructed bridge low carbon construction scheme dataset showed that the proposed model achieved good accuracy with named entity recognition tasks. The comparative analysis with the construction scheme of the project verified the validity of the proposed construction scheme considering carbon emission constraints, which can provide support for the decision of the low-carbon construction scheme of bridges. [ABSTRACT FROM AUTHOR]

During the last decades, rammed earth technology has been explored worldwide because of a growing concern for sustainable constructions. A relevant, contemporary technical culture of rammed earth developed in the south-west of Western Australia (WA) from the 1970 s. Several examples of residential, educational, commercial and community buildings in the region were built in rammed earth during the last 40 years. An active group of professionals involved in rammed earth construction operates in the region. This study assesses the state of the art of rammed earth construction practice in the south-west of WA based upon a qualitative and quantitative questionnaire to the professionals involved in the local rammed earth construction industry. The questionnaire collects data on five major technical areas: (i) strengths and weaknesses of rammed earth technology; (ii) opportunities and deterrents to employ rammed earth in the south-west of WA; (iii) rammed earth materials and on-site equipment and construction process; (iv) aesthetic and design qualities of rammed earth buildings; and (v) thermal performance of rammed earth buildings. The study's objective is to analyse the potential of the rammed earth technology within the local construction sector, engaging the local industry to identify the paths for further development of the current guidelines.

The fragmented nature of construction operations makes it challenging to implement carbon-reduction strategies. However, attaining a holistic construction sector decarbonisation hinges upon ensuring all aspects of a construction project’s lifecycle are decarbonised, including the construction process stage. Therefore, to mitigate the implementation challenge of reducing the levels of carbon involved in construction processes, this study attempts to synthesise and categorise carbon-reduction strategies that could be employed to decrease the carbon footprint during a construction projects’ delivery. To achieve the aim of this study, a systematic literature review approach was adopted. Based on this technique, a total of 26 relevant articles within the built environment research area were eligible for the study, and their analysis revealed 56 carbon minimisation measures, which were summarised into nine distinct categories to ease their application and overcome the construction operations’ complexities. The nine categories include material transport, waste transport, materials and equipment, waste, materials, on-site office, on-site lighting, on-site transportation of material and equipment, and construction methods. The findings of this study provide contractors with a suite of measures that can be deployed to reduce the carbon impact of construction project delivery.

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. [ABSTRACT FROM AUTHOR]

With the development of the engineering construction industry, knowledge became an important strategic resource for construction enterprises, and knowledge graphs are an effective method for knowledge management. In the context of peak carbon dioxide emissions and carbon neutrality, low carbon emission became one of the important indicators for the selection of construction schemes, and knowledge management research related to low carbon construction must be performed. This study investigated a method of incorporating low-carbon construction knowledge into the bridge construction scheme knowledge graph construction process and proposed a bridge construction scheme recommendation method that considers carbon emission constraints based on the knowledge graph and similarity calculation. First, to solve the problem of the poor fitting effect of model parameters caused by less annotation of the corpus in the bridge construction field, an improved entity recognition model was proposed for low-resource conditions with limited data. A knowledge graph of low carbon construction schemes for bridges was constructed using a small sample dataset. Then, based on the construction of this knowledge graph, the entities and relationships related to construction schemes were obtained, and the comprehensive similarity of bridge construction schemes was calculated by combining the similarity calculation principle to realize the recommendation of bridge construction schemes under different constraints. Experiments on the constructed bridge low carbon construction scheme dataset showed that the proposed model achieved good accuracy with named entity recognition tasks. The comparative analysis with the construction scheme of the project verified the validity of the proposed construction scheme considering carbon emission constraints, which can provide support for the decision of the low-carbon construction scheme of bridges.

Low carbon construction has recently become an international issue as construction companies, governments, and communities have witnessed an increasing concern about the degradation of natural resources and pollution in the environment. Although literature abounds with studies investigating the positive impact of low carbon construction on decreasing the emission of carbon in the construction industry, following a low carbon practice might come into conflict with job satisfaction amongst construction site managers, which in turn can negatively affect companies' performances. This study examines the mediating effect of job stress to investigate the indirect effects of low carbon waste practices on job satisfaction. Data from a survey of 110 site managers of construction companies in Malaysia were examined through the application of the partial least squares technique. The results of the study advocates that unlike the reduce waste management practices, the two other low carbon waste practices, recycle and reuse management practices, positively and directly affected job stress. It was also revealed that only recycle waste management practices negatively and indirectly affected construction site managers' job satisfaction via job stress. The findings of the research presents an extent of caution for the managers of those construction companies which execute low carbon waste practices regarding the potential impact of low carbon practices on job stress and job satisfaction. From the job stress and job satisfaction points of view, the construction companies should give priority to waste reduction practices amongst low carbon waste practices. [ABSTRACT FROM AUTHOR]

The extensive use of traditional binders (cement/lime) has caused serious resource consumption, environmental degradation, and carbon emission issues. Recycling industrial waste as a novel waste-based binder is a promising alternative. This paper purports to effectively stimulate the activity of steel slag (SS) and develop a novel eco-friendly pavement base mixture (NEPBM). A series tests of microscopic characterization, unconfined compressive strength (UCS), splitting strength (STS), freeze-thaw cycles, shrinkage, and field application were conducted to evaluate the performance of recycled concrete aggregate (RCA) pavement bases stabilized with alkali-activated SS based material (denoted as ACM). The results show that the potential activity of waste SS is strongly activated by alkaline activators, and the depolymerization-diffusion-polymerization reaction occurs to generate abundant additional gel products, thus the strength of ACM at 28-day reaches to 45.24 MPa. The mixtures with 50% ACM substitution rate is close to the control group in performances of UCS, STS, and resistance freeze-thaw cycle. The decrease (12.1 ×10−6) of dry shrinkage coefficient is far higher than the increase (1.11 ×10−6·℃−1) of temperature shrinkage coefficient, which effectively reduces the risk of early cracking. The field application indicates that the UCS of NEPBM at 7-day reaches to 4.26 MPa, which meets the technical requirements for heavy traffic of classⅠhighways in China, the construction cost of NEPBM reduces to 15.72 USD/m3, and the CO 2 emissions reduces to 31.335 kg/m3. The results show that using NEPBM as a pavement base is a viable solution, which will be conducive to promoting the development of transportation infrastructure with excellent shrinkage performance and lower carbon footprint emissions. • An alkali-activated steel slag base cementitious material (ACM) was developed as alternative pavement binder. • The ACM was strongly activated by alkaline activators of SF-CaO-Na 2 SO 4. • Mechanism model of alkali-activated reaction was constructed. • The developed NEPBM achieved considerable comprehensive performance when the substitution rate of ACM was 50%. • Compared with TCSM, the NEPBM of construction cost and CO 2 emission were reduced by 15.72 USD/m3 and 31.335 kg/m3. [ABSTRACT FROM AUTHOR]

Purpose -- The purpose of this paper is to evaluate the risks of building defects associated with rapid advancement of "green" construction technologies. It identifies the methods adopted by the sector for the determination of pre-construction defects that are framed within the context of, traditional; scientific; and professional design approaches. These are critically evaluated and utilised in attempts to mitigate defects arising from diffusing low carbon construction innovations. Design/methodology/approach -- The paper takes the form of an evaluative literature review. Polemic in orientation, the paper critically compares two periods of time associated with rapid advancement of innovation. The first, the post-Second World War housing boom is synonymous with a legacy of substandard buildings that in many cases rapidly deteriorated, requiring refurbishment or demolition shortly after construction. The second, is today's "green" technology "shift" with its inherent uncertainty and increased risk of latent building defects and potential failure to deliver meaningful long-term performance. Central to this is an exploration of the drivers for innovation, and subsequent response, precautionary measures initiated, and the limitations of institutionalised systems to identify and mitigate defects. Similarities and differences between these historical periods frame a discussion around the theoretical approaches to defects and how these may be limited in contemporary low carbon construction. A conceptual framework is presented with the aim of enhancing the understanding for obviation of defects. Findings -- Sufficient commonality exists between the periods to initiate a heightened vigilance in the identification, evaluation and ideally the obviation of defects. Design evaluation is not expressly or sufficiently defect focused. It appears that limited real change in the ability to identify defects has occurred since the post-war period and the ability to predict the performance of innovative systems and materials is therefore questionable. Attempts to appraise defects are still embedded in the three principle approaches: traditional; scientific; and professional design. Each of these systems have positive characteristics and address defect mitigation within constrains imposed by their very nature. However, they all fail to address the full spectrum of conditions and design and constructional complexities that lead to defects. The positive characteristics of each system need to be recognised and brought together in an holistic system that offers tangible advantages. Additionally, independent design professionals insufficiently emphasise the importance of defect identification and holistic evaluation of problems in design failure are influenced by their professional training and education. A silo-based mentality with fragmentation of professional responsibility debases the efficacy of defect identification, and failure to work in a meaningful, collaborative cross professional manner hinders the defect eradication process. Research limitations/implications -- Whilst forming a meaningful contribution to stimulate debate, further investigation is required to tangibly establish integrated approaches to identify and obviate defects. Practical implications -- The structured discussion and conclusions highlight areas of concern for industry practitioners, policy makers, regulators, industry researchers and academic researchers alike in addressing and realising a low carbon construction future. The lessons learned are not limited to a UK context and they have relevance internationally, particularly where rapid and significant growth is coupled with a need for carbon reduction and sustainable development such as the emerging economies in China, Brazil and India. Social implications -- The carbon cost associated with addressing the consequences of emerging defects over time significantly jeopardises attempts to meet legally binding sustainability targets. This is a relatively new dimension and compounds the traditional economic and societal impacts of building failure. Clearly, blindly accepting this as "the cost of innovation without development" cannot be countenanced. Originality/value -- Much research has been undertaken to evaluate post-construction defects. The protocols and inherent complexities associated with the determination of pre-construction defects have to date been largely neglected. This work attempts to rectify this situation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The layer coefficients of CACSM from field test locations ranged from 0.22 to 0.24. By contrast, for granular and cement-treated bases, these values were between 0.07 and 0.14 and between 0.17 and 0.20. • The mechanical property test verified the self-healing ability of CACSM; coal ash appeared to considerably influence the secondary curing of the specimens. • The use of 100% CACSM as a pavement base is a viable solution that can contribute to the development of transportation infrastructure with enhanced concrete durability and reduced carbon footprint emissions. Coal fly ash (CFA) and coal bottom ash (CBA) are coal combustion's primary solid waste products. This solid waste management is a substantial challenge for power plants and local authorities. In order to apply coal ash as a pavement base material, the relationship of the mixture's mechanical properties with structural design parameters for pavement design and analysis must be explored. No study has investigated the mechanical behavior of the 100% coal ash cement stabilized material (CACSM) as a pavement base layer. Therefore, this study aimed to investigate the structural layer coefficient of CACSM used in the American Association of State Highway and Transportation Officials (AASHTO) 1993 pavement design guide. The study consisted of laboratory material characterization and field evaluation. The mechanical property test revealed that CACSM has a self-healing ability; coal ash appeared to influence the secondary curing of the specimens significantly. Strength towards the ends of stage I and stage II showed the influence of high pozzolanic on the CACSM, which resulted in improved long-term performance. The layer coefficients of the locations in the field test ranged from 0.22 to 0.24. By contrast, for the granular base and cement-treated base, these values were 0.07 to 0.14 and 0.17–0.20, respectively. The study findings show that CACSM as a pavement base is a viable solution that can help develop transportation infrastructure with enhanced concrete durability and lower carbon footprint emissions. [ABSTRACT FROM AUTHOR]

Abstract: Low-carbon prefabricated modular construction systems, using prefabricated engineered solid wood panel construction systems, such as load-bearing cross-laminated timber panels, and ‘design for disassembly’ principles will offer significant opportunities for greenhouse gas emission reduction and waste avoidance, among other benefits. However, introducing such innovative and sustainable construction systems to the Australian construction industries and housing markets has its challenges. This paper explores the opportunities offered by an innovative low carbon construction system using cross-laminated timber (CLT, also known as cross-lam) panels to improve the design and delivery of urban infill housing of the Australian construction market. CLT construction has been developed around 1996 in Europe, mainly in Austria and Germany: thick layers of timber boards are glued crosswise in different directions to increase loadbearing capacity. This article describes a multi-disciplinary research project into engineered timber panels which aims to transform the Australian construction and development industry, involving a range of key partners. This project aims to introduce CLT panels as a way to build with a lightweight prefabricated low-carbon construction system that is advantageous for urban infill and residential buildings in the range of 4–10 stories height. The challenges, research questions and advantages of this new engineered timber system are explained, and a research methodology for further research is presented. [Copyright &y& Elsevier]