Mineral carbonation is a technology for capturing and storing COsub.2 in solid minerals. When mineral carbonation is used to produce construction materials, the quantification of the COsub.2 uptake ...of these products is of the utmost importance, as it is used to calculate the COsub.2 footprint of the product and/or carbon offset. The COsub.2 uptake is generally determined by measuring the COsub.2 content of a material before and after accelerated carbonation. This approach, however, does not take hydration and dehydroxylation reactions into account that may occur during carbonation, and it can therefore under- or overestimate the COsub.2 uptake. Thus, a more accurate and practical method to determine COsub.2 uptake, which also accounts for hydration and dehydroxylation reactions, is proposed in this paper. This method is based on analytical methods to determine the dry mass and the COsub.2 content of the solid products before and after carbonation, and on the calculation of the COsub.2 uptake by the following equation: COsub.2 uptake (wt.%) = COsub.2 carbonated (wt.%) × (weight after carbonation (g)/weight before carbonation (g) − COsub.2 initial (wt.%), with COsub.2 carbonated being the COsub.2 content in g/100 g dried carbonated material, and COsub.2 initial being the COsub.2 content in g/100 g dried initial material, i.e., before carbonation. The “weight before carbonation” is the dry weight of the initial material, and the “weight after carbonation” is the product’s dry weight after carbonation. In this paper, we show that up to 44% under- or overestimation of COsub.2 uptake can occur when hydration and dehydroxylation reactions are not taken into account during mineral carbonation.
Fired perforated brick is a common material in modern construction industry. This paper introduced the production technology and equipment of fired perforated brick. Based on the research status of ...domestic and foreign scholars, technical difficulties and corresponding solutions of production process were analyzed and summarized. And the future of fired perforated bricks production equipment was discussed.
Building Procurement Morledge, Roy; Smith, Adrian
2013, 2013-02-19, 2013-01-14
eBook
As an industrial process, construction is unique in that the method of procurement of any built asset (building, infrastructure or process plant) defines many of the subsequent management processes ...that take place during the building phase – a very different situation to the purchase of goods and services in most other industries. The procurement process is therefore central to the success of any construction project and many of the problems which impact construction projects can be traced back to the procurement phase, so a good understanding of the methods of procurement and the influence it has on project success is essential for all those working in the industry.Much has changed in the global construction industry since publication of the first edition of Building Procurement,for example the global liquidity banking crisis and the debt burden of many major economies. This new edition has been rewritten to take account of these significant developments, but at its core it continues to provide a critical examination and review of current procurement practices in the UK, continental Europe (including EU procurement procedures), China and the USA. It retains its original strong emphasis on the need for clients to establish achievable objectives which reflect the project business case and focuses on development of suitable strategies and management structures to meet those objectives in the current construction climate.Building Procurementwill be essential reading for senior undergraduate and postgraduate students of construction management and practitioners working in all areas of construction management.Review of the first edition'...a thorough and comprehensive investigation of building procurement...' Construction Management and Economics
Objectives The construction industry accounted for >20% of all fatal occupational accidents in Europe in 2014. Leadership is an essential antecedent to occupational safety. The aim of the present ...study was to assess the influence of transformational, active transactional, rule-oriented, participative, and laissez-faire leadership on safety climate, safety behavior, and accidents in the Swedish and Danish construction industry. Sweden and Denmark are similar countries but have a large difference in occupational accidents rates. Methods A questionnaire study was conducted among a random sample of construction workers in both countries: 811 construction workers from 85 sites responded, resulting in site and individual response rates of 73% and 64%, respectively. Results The results indicated that transformational, active transactional, rule-oriented and participative leadership predict positive safety outcomes, and laissez-faire leadership predict negative safety outcomes. For example, rule-oriented leadership predicts a superior safety climate (β=0.40, P<0.001), enhanced safety behavior (β=0.15, P<0.001), and fewer accidents odds ratio (OR) 0.78, 95% confidence interval (95% CI) 0.62–0.98. The effect of rule-oriented leadership on workers' safety behavior was moderated by the level of participative leadership (β=0.10, P<0.001), suggesting that when rules and plans are established in a collaborative manner, workers' motivation to comply with safety regulations and participate in proactive safety activities is elevated. The influence of leadership behaviors on safety outcomes were largely similar in Sweden and Denmark. Rule-oriented and participative leadership were more common in the Swedish than Danish construction industry, which may partly explain the difference in occupational accident rates. Conclusions Applying less laissez-faire leadership and more transformational, active transactional, participative and rule-oriented leadership appears to be an effective way for construction site managers to improve occupational safety in the industry.
Construction projects in India are experiencing widespread delays. Due to a dramatic shift in the capacity and volume of the Indian construction sector over the last decade, the need of a systematic ...analysis of the reasons of delays and developing a clear understanding among the industry professionals are highly crucial. Using a selected set of 45 attributes, this research first identified the key factors impacting delay in Indian construction industry and then established the relationship between the critical attributes for developing prediction models for assessing the impacts of these factors on delay. A questionnaire and personal interviews have formed the basis of this research. Factor analysis and regression modelling were used to examine the significance of the delay factors. From the factor analysis, most critical factors of construction delay were identified as (1) lack of commitment; (2) inefficient site management; (3) poor site coordination; (4) improper planning; (5) lack of clarity in project scope; (6) lack of communication; and (7) substandard contract. Regression model indicates slow decision from owner, poor labour productivity, architects' reluctance for change and rework due to mistakes in construction are the reasons that affect the overall delay of the project significantly. These findings are expected to be significant contributions to Indian construction industry in controlling the time overruns in construction contracts.
This paper presents a systematic Structural Equation Modeling (SEM) based approach for Prospective Safety Performance Evaluation (PSPE) on construction sites, with causal relationships and ...interactions between enablers and the goals of PSPE taken into account. According to a sample of 450 valid questionnaire surveys from 30 Chinese construction enterprises, a SEM model with 26 items included for PSPE in the context of Chinese construction industry is established and then verified through the goodness-of-fit test. Three typical types of construction enterprises, namely the state-owned enterprise, private enterprise and Sino-foreign joint venture, are selected as samples to measure the level of safety performance given the enterprise scale, ownership and business strategy are different. Results provide a full understanding of safety performance practice in the construction industry, and indicate that the level of overall safety performance situation on working sites is rated at least a level of III (Fair) or above. This phenomenon can be explained that the construction industry has gradually matured with the norms, and construction enterprises should improve the level of safety performance as not to be eliminated from the government-led construction industry. The differences existing in the safety performance practice regarding different construction enterprise categories are compared and analyzed according to evaluation results. This research provides insights into cause-effect relationships among safety performance factors and goals, which, in turn, can facilitate the improvement of high safety performance in the construction industry.
While sustainable construction practices effectively reduce environmental impact, their exclusive focus on environmental, economic, and social goals limits their ability to actively foster positive ...transformation and ecosystem restoration. Addressing the growing challenges in the built environment necessitates a shift to regenerative practices within the construction industry. Unlike sustainability, regenerative practices go beyond the concept of merely sustaining the status quo; they are geared towards actively enhancing and restoring the built environment over time. However, implementing these practices is less prominent in the construction industry due to the absence of a suitable tool for evaluating their expected performance outcomes. This study bridges this gap by introducing a novel performance evaluation framework for implementing regenerative construction practices, establishing a benchmark for implementation. Through an extensive literature review and data collection from a committee of regenerative outcome leads, we employ the Fuzzy Analytical Hierarchical Process (FAHP) to establish interconnections among key regenerative performance criteria. Results highlight the dominant significance of “Healthy, more resilient, and connected communities,” surpassing other criteria like “Thriving and prosperous natural systems,” “Prosperous and resilient local economies,” and “Net-positive environmental development.” The proposed evaluation framework offers theoretical and practical implications, fostering a new theoretical approach that exceeds sustainability standards and provides tangible guidance for construction decision-makers.
•Shift from sustainability to regeneration ensures more positive transformation.•The framework helps to evaluate the expected performance of regenerative practices.•FAHP-based study reveals key criteria for resilient communities.•“Healthy communities” outweigh other criteria in significance.•The Framework offers theoretical and practical guidance for decision-makers.
This study aims to identify the factors that influence the adoption of smart contracts in the UK construction sector. A deductive questionnaire-based approach informed by the ...technology-organisation-environment (TOE) model is adopted. The framework is comprised of twelve independent variables and one dependent variable of smart contracts use intention. Ten hypotheses are developed to statistically test the causal relationships between the eleven variables of the research model. The study adopts a convenience sampling approach, with the population of interest being primarily drawn from among UK construction practitioners. The results generated from linear regression analysis suggest that the following four factors have a significant influence on the adoption of smart contracts: supply chain pressure, competitive pressure, top management support, and observability. The descriptive statistics obtained also offer a greater understanding of the perceptions and attitudes towards smart contracts across the UK construction sector. The results demonstrate the usefulness of a perception-based model that utilises the TOE framework to assess facets that influence the adoption of smart contracts. The study contributes to innovation diffusion studies in construction project management and supports "early adopters" at the footfall of the technology's diffusion curve.
Once the tide recedes and leaves a significant amount of stranded seaweed on the coast, marine macroalgae pose a serious threat to the surrounding area. Through this work, we considered a large-scale ...application of stranded macroalgae in building construction. For the first time we studied the impact of incorporating Sargassum mitucum seaweed fiber in replacement of flax fiber used for a standard structural cob. Thus, cob specimens were elaborated and analyzed to evaluate their compressive and hygrothermal performances. It was found that the compressive strength and water vapor resistance factors of cob decreased with the algae content. Additionally, the obtained results showed that a cob made with Sargassum muticum algae presented better thermal (insulation and inertia) and hygroscopic properties than those of a cob made with a flax fiber. Indeed, the replacement of flax straw by algae lead to a reduction in the thermal conductivity by 38% when compared to the standard cob with 2.5% of flax straw fiber. Consequently, numerical simulation showed a reduction in the energy needs in buildings made with an algae-based cob when compared to those made with a flax-based cob. This study can contribute to a global environmental and economic issue, i.e., the valorization of brown algae on a large scale. Indeed, the worldwide knows the largest sea of sargassum algae extent measures over 8850 kmsup.2. This huge mass of brownish algae is expanding every year, which now covers an area from Africa to the Caribbean. It weighs more than 20 million tons and extends from the Gulf of Mexico to the west coast of Africa. We show that stranded algae, which are considered as wastes, have the ability to improve the mechanical and hygrothermal performance of cob-based material.
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