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Worldwide, an increasingly huge number of end-of-life tires (ELTs) are disposed of in landfills, illegally dumped, or otherwise unaccounted for, which causes significant environmental and socioeconomic issues. Finding sustainable engineering solutions to recycle and reuse ELTs, which transform them from unwanted waste into useful resources, has become a priority. In geotechnical engineering, researchers have performed laboratory and field tests to determine the mechanical properties of innovative geomaterials that consist of soil–rubber mixtures (SRMs) [i.e., gravel–rubber mixtures (GRMs)] that are obtained using recycled ELT-derived granulated rubber aggregates. Suitable engineering properties and low installation cost encourage the use of GRMs and SRMs in many applications, such as in free-draining energy-adsorption backfill material for retaining walls, underground layers for liquefaction mitigation and geotechnical seismic isolation systems for structures and infrastructures. However, due to the heterogeneity of SRMs, their ultimate adoption as geomaterials must be supported by constitutive relationships that can accurately describe their mechanical behavior under typical field loading conditions. The aim of the paper is to evaluate the effectiveness and limits of the hardening soil model with small strain stiffness (HS-small), which is present in many finite-element (FE) codes, to model the behavior of GRMs in geotechnical engineering applications. An extensive finite-element method simulation of drained triaxial tests was performed. [ABSTRACT FROM AUTHOR]

Green architecture, engineering, and construction (AEC) projects are deemed more complicated compared with their traditional counterparts. They have been reported to have relatively more frequent delays and higher cost growth. The AEC literature has repeatedly highlighted the importance of leadership for sustainable design and construction and the need for team integration for optimal outcomes. However, studies exploring leadership in the context of green AEC projects are limited. Transformational leadership is a highly regarded theory that is known for its potential to effectively facilitate team integration. This empirical study tests the role of shared transformational leadership received by team members in improving team performance through team integration for green AEC project teams. We collected data from 103 individuals working in nine Leadership in Energy and Environmental Design (LEED) projects in the US. We analyzed the data using structural equation modeling (SEM). Our findings suggest that transformational leadership received by team members is positively related with perceived team performance, and this relationship is mediated through perceived team integration. The study is a pioneer in examining leadership for sustainability and mediation effects of team integration in the AEC literature. The outcomes urge for a change in green AEC project teams to think beyond project delivery systems and practices and incorporate transformational leadership across organizational and communicational tiers of project teams through team procurement, project management, and skill development and training. [ABSTRACT FROM AUTHOR]

As an important ecofriendly material in pavement engineering, bioasphalt has received more and more attention recently. However, the negative high-temperature behavior of bioasphalt limits its extensive application. With the purpose of enhancing the bioasphalt high-temperature behavior, polyphosphoric acid (PPA) was used to modify bioasphalt. The PPA/bio-oil composite–modified asphalt's high-temperature behavior was investigated by the dynamic shear rheometer (DSR) test. The low-temperature behavior was evaluated by using the bending beam rheometer (BBR) test. Finally, the modification mechanism of modified asphalt was analyzed by carrying out a Fourier-transform infrared reflection (FTIR) test. The results indicated that compared with the neat asphalt, the rutting index of PPA/bio-oil composite–modified asphalt was significantly improved. Also, it had excellent low-temperature crack resistance. As the bio-oil and PPA contents in respect to the weight of neat asphalt were 15% and 5%, respectively, PPA/bio-oil composite–modified asphalt performance was optimal. Shear time and shear rate did not have a remarkable effect on PPA/bio-oil composite–modified asphalt performance. Moreover, bio-oil did not affect the chemical structure of the neat asphalt. But, PPA generated new chemical functional groups with neat asphalt and produced chemical modification. This research makes pavement engineering greener, more economical, and environmentally friendly. [ABSTRACT FROM AUTHOR]

The effective reduction of cement content in pavement concrete without compromising its fresh, mechanical, and durability properties can lead to more economical and sustainable pavement engineering. Because a reduction in cement content in concrete can be achieved by improving the particle packing of aggregates, this study attempted to improve a practical mix design procedure based on both theoretical and experimental particle packing methods. In this study, optimum aggregate blends were first identified using the Modified Toufar Model, which indicated good correlation with the experimental packing results based on a combined void content test. The Modified Box Test was then used to evaluate the fresh concrete performance and to justify the effectiveness of cement reduction. The results indicated that cement content could be reduced by up to 56 kg/m3 from the reference mix with the optimum aggregate gradation. The results from hardened concrete tests, such as compressive strength, flexural strength, and resistivity, confirmed that concrete properties were not compromised by the reduced cement content. Freeze-thaw resistance was improved with up to an 11% increase in the relative dynamic modulus at 300 freeze-thaw cycles. The optimum mixes also demonstrated reduced shrinkages, with a 12%–20% reduced strain at 180 days of free shrinkage and a delayed cracking age based on the restrained shrinkage test. Based on the laboratory test results, an improved mixture design procedure aided by the particle packing degree and the minimum excess paste-to-aggregates volume ratio is presented. [ABSTRACT FROM AUTHOR]

The comparative performance between steel slag (S) and limestone (L) as aggregates in dense-graded asphalt concretes were investigated in this research. The performance tests for fatigue cracking were undertaken using indirect tensile strength (ITS) tests, indirect tensile fatigue life (ITFL) tests, and indirect tensile resilient modulus (MR) tests. Dynamic creep tests and wheel tracking tests were also performed to assess the rutting behavior of these pavement materials. A heavy metal leaching test was also carried out to ensure that asphalt concrete with the usage of S, as a sustainable aggregate, was safe for the environment. The results indicated that asphalt concretes with S had better Marshall's stability than the asphalt concretes with L, even though they had slightly less ITS values. The ITFL and MR of S asphalt concretes were higher than those of L asphalt concretes, indicating higher fatigue cracking resistance. The MR of S asphalt concretes were found to be higher than the required 3,100 MPa value recommended by AASHTO, while L asphalt concretes did not meet this requirement. In addition, the dynamic creep and wheel tracking test results showed that the S asphalt concretes had superior resistance to permanent deformation as compared to the L asphalt concretes. The usage of medium-sized S aggregate in developing asphalt concrete was evidently more sustainable in terms of engineering and economic perspectives than the usage of large-sized S aggregate. The research results indicated that the sustainable usage of S in asphalt concrete was suitable for the development of heavy traffic volume roads. [ABSTRACT FROM AUTHOR]

The University of Texas at Austin's (UT-Austin) Civil, Architectural, and Environmental Engineering (CAEE) department has taken several steps toward improving the preparation of architectural engineering students with respect to modern engineering tools, including the computing tools commonly used in engineering practice. This is most evident in the integration of building information modeling (BIM) throughout the architectural engineering (ARE) undergraduate program curriculum, from early design (building envelope design/massing), to integrated engineering systems design (structural and mechanical integrated with architectural design), and analyses beyond design, such as scheduling and cost estimating. BIM was identified as a unifying aspect of the ARE curriculum. Starting in fall 2008, the ARE faculty began to introduce BIM into the ARE curriculum one year at a time, starting with the freshman year. By fall 2011, it had been introduced into our capstone course, ARE 465. In 2013, an entire course entitled ARE 376, Building Information Modeling for Capital Projects, was added to the curriculum as a technical elective. The introduction of BIM into the ARE program is intended to improve the preparation of students with respect to design, including the computing tools commonly used in engineering design. This paper describes experiences of UT-Austin's CAEE department in implementing BIM across the ARE undergraduate curriculum, carried out over a period of 10 years. Implementation steps, courses affected, and lessons learned to date are documented. [ABSTRACT FROM AUTHOR]

To increase the long-term sustainability of architecture and engineering decisions, this research combined theory from behavioral science and civil infrastructure design to examine whether redesigning sustainability decision-making tools can alleviate potential status quo bias in planning and design decisions. Using case studies to simulate real-world decision environments, we empirically tested the combined effect of two modifications to the Envision Rating System for Sustainable Infrastructure. One modification provided engineers with sustainability points corresponding to the highest level of achievement, with any change to a lower level leading to a loss of points. The second modification showed engineers an exemplary project to serve as a feasibility example. The combined modifications produced significant gains in sustainability using predefined metrics. One concern is that these modifications work because decision makers are unaware of their effects. To assess this, we disclosed the modifications to another group of engineers. The disclosure had no significant effect on the gains in sustainability performance. We then repeated the experiment with groups. Similar gains in sustainability were achieved by groups who received the combined modifications. Our results suggest ways of using insights from behavioral decision theory to improve the growing array of tools used to plan for sustainability not only in large-scale infrastructure projects but also in a range of other upstream applications that determine downstream consumer choices. [ABSTRACT FROM AUTHOR]

As continued globalization of the world's economic, environmental, and societal interactions strains the planet to meet anthropogenic demands, universities are striving to integrate sustainability education into engineering curricula intended to prepare students for global challenges facing today's engineers. Concurrently, the Accreditation Board for Engineering and Technology (ABET) has potential changes related to outcomes related to sustainability. Current practice is to evaluate many student educational outcomes, including those in sustainability, at the end of collegiate careers, primarily through the senior design course. This study compares results from the application of a comprehensive holistic sustainability rubric assessment tool to three years of student projects in two stand-alone sustainable engineering courses and two senior design courses, intended to assess dissimilarities in student outcomes and locate causality, in the context of sustainability. The authors present two potential factors contributing to discrepancies in student outcomes: (1) rubrics do not contain clear elements of sustainability; and (2) senior design course syllabuses are full, and offer strategic approaches to overcoming these barriers institutionally and nationally. [ABSTRACT FROM AUTHOR]

This paper presents practical guidance and resources for use during the construction phase developed by the Construction Industry Institute (CII) Research Team (RT) 304, Sustainability Practices and Metrics for the Construction Phase of Capital Projects. It introduces 54 construction phase sustainability actions (CPSAs) that project teams can use during project execution to prioritize and carry out sustainability solutions. Further, it discusses the results of the sustainability survey on current and future capital project implementation of CPSAs, with a focus on frequency of use and barriers to deployment. By following the guidance provided here for adopting these CPSAs, owners and contractors will be better prepared to implement sustainability actions during the construction phase of their capital projects. This paper's primary contributions are the identification of construction-related decisions and actions to advance sustainability implementation, the provision of detailed practical guidance for effective application, and the validation of the 54 CPSAs in the catalog based on the frequency of current and likely future application. [ABSTRACT FROM AUTHOR]

The ASCE Body of Knowledge and the ABET Engineering Accreditation Commission have emphasized a broad set of competencies required by 21st century civil engineers. In addition to competencies that are traditionally technical, these organizations recognize that professional competencies such as leadership, the ability to design sustainable systems, effective communication, and interdisciplinary teamwork are among the many skills required by engineers of the future. To develop and enhance all of these proficiencies within the undergraduate curriculum, there is a need to take an approach that interconnects all of these outcomes throughout the curriculum, or a "networked" approach. This paper discusses service learning as a potential approach for facilitating the broad set of foundational, technical, and professional learning outcomes cited by ASCE and ABET, by investigating two case studies within the Engineering Projects in Community Service program at Purdue University. The case studies are two service-learning projects from one large, multidisciplinary, vertically integrated student design team. One project focuses on sustainable and energy efficient housing for Habitat for Humanity (HFH) in Indiana, whereas the other project focuses on affordable houses for HFH in Haiti. The current analysis of these cases suggest that service-learning projects can provide a unique learning experience for the students to develop and synthesize the broad set of foundational, technical, and professional skills by integrating learning outcomes [ABSTRACT FROM AUTHOR]

The construction industry is experiencing changes in the tools and techniques used in the planning for high productivity, safety, and sustainability. These changes have not been seen much in the preconstruction planning (PCP) stage. The PCP is highly individualistic in nature, in which planners/contractors use their past experience to plan a project within the constraints of time, cost, and quality. The use of planning techniques in the PCP stage has been the subject of research, development, and implementation for a long time; however, at present, importance is being placed on the use of different tools. Tools like knowledge-based systems, computer graphics, and a combination of the two have been reported in the literature. Literature also suggests the use of geographic information systems (GIS) as a recent tool in the PCP stage. A structure that is to be developed becomes an important component of its neighborhood. It is closely related to all other existing facilities in its surroundings; hence, its construction should not be planned in isolation but in reference to its locality, existing facilities/ utilities, topography, and so on. In the PCP stage, consideration should be given to its surroundings, in which the use of GIS has been found to be helpful. Therefore, the primary objective of the present study is to explore the potential application areas of GIS, as a tool, in the PCP stage. The present study informs practitioners in the construction industry about the application areas of GIS for their wider use in real-life projects. Finally, research areas worthy for further investigation are highlighted. [ABSTRACT FROM AUTHOR]

This paper presents the current state of practice in the development of ultrahigh-performance concrete (UHPC) bridge construction in Malaysia. Since 2006, Dura Technology (DT) has pioneered research in the optimal uses of UHPC in bridge construction through its Sustainable Bridge Construction Initiative. After several years of research and development work, DT has collaborated with the Malaysia Works Ministry to design and build bridges in some of their bridge projects, especially those bridges under the rural development program where sourcing of material, site access, and construction method are major challenges when using conventional methods. The most current information and details on the completed and ongoing UHPC bridge projects in Malaysia are presented. To date, a total of 26 segmental UHPC bridge projects have been constructed and opened for service. In this paper, a selected UHPC bridge case study is examined in terms of the design aspects, quality control, constructability, and of how UHPC has helped to make the bridge more affordable, sustainable, easier to build, and economical. [ABSTRACT FROM AUTHOR]

Geopolymers are an alternative binder to portland cement in the manufacture of mortars and concrete, as its three-dimensional aluminosilicate network imparts excellent mechanical properties. Use of geopolymers in place of ordinary portland cement is favored owing to the possible energy and carbon dioxide savings. River sand is another construction industry material that needs development of a sustainable alternate in India. Geopolymerization of fly ash amorphous silica mixtures is employed to produce fine aggregates as a possible replacement to river sand. Geopolymerization of fly ash amorphous silica mixtures in 10 M NaOH solution at 100°C for 7 days produced fine aggregates [termed fly ash geopolymer sand (FAPS)] that had comparable grain size distribution, specific gravity, and improved frictional resistance with river sand. The FAPS particles exhibited more alkaline pH (12.5) and higher total dissolved solids (TDS) concentration () in comparison to the river sand specimen ( and ). However, when used as fine aggregate in mortar, FAPS-mortar specimens develop similar pH, lower TDS, similar compressive strength, and modulus in relation to river sand-mortar specimens. The experimental results suggest that FAPS particles have the potential to replace river sand in the manufacture of mortar and concrete. [ABSTRACT FROM AUTHOR]

Sustainability of buildings is one of the main aims in the construction industry. In achieving sustainability, maintenance of buildings and its facilities, which include planning, implementation, and outcome of maintenance activities, becomes an important criterion. This paper aims to identify the significant characteristics of scheduled and condition-based maintenance in office buildings through reviews of relevant literature and a questionnaire survey. The significance of the characteristics was identified through ranking analysis. A semistructured interview was conducted to obtain further details on the characteristics and measures to enhance efficiency of the characteristics. The findings reveal that the dominant characteristics for scheduled maintenance include quality of spare part and material, the level of labor skill and knowledge, and budget allocation for maintenance labor, whereas for condition-based maintenance, the dominant characteristics are the level of manager skill and knowledge, reliability of maintenance data, and financial allocation for the maintenance manager. The study concludes that these dominant characteristics should be considered in the implementation of maintenance strategies. [ABSTRACT FROM AUTHOR]

In the construction sector, innovation is cocreated in a multiparty environment and shaped by the requirements of the project. Therefore, the analysis of innovation at the project level is essential. This research investigates the innovation process in construction projects. It proposes a framework to explore various components of innovation, including the drivers, inputs, enablers, barriers, innovative activities, benefits, and impacts. The framework is employed in four case studies concerning award winning projects in the UK. The primary source of product, process, and organizational innovations in these cases has been agendas driven by environmental sustainability. Collaborative working among team members and strong commitment proved to be the primary enablers of innovation; reluctance, inexperience, and cost were regarded as barriers to innovation. This study helps to develop a better understanding of the interorganizational nature of construction innovations, thereby improving innovation performance. The developed framework is expected to be applicable to other project-based environments. [ABSTRACT FROM AUTHOR]

For sustainable engineering to contribute to sustainability, curricular reforms are needed to train sustainability-conscious engineers. Examining student perceptions of sustainability education can provide insights for benchmarking the current quality of a curriculum and for identifying strategies for reforming a curriculum. Thus, the goal of this study was to examine student interest in, knowledge of, and experiences related to sustainability in civil and environmental engineering (CEE) at the Georgia Institute of Technology (Georgia Tech). A survey was developed and administered to students () enrolled in CEE capstone courses. The results indicated that although students are interested in sustainable development, there is potential for further enhancing sustainability learning. In addition, students reported that CEE courses strongly impacted their learning, which underscores the importance of curricular quality. Finally, although students were generally satisfied with CEE sustainability education, they cited the need for more guidance on integrating sustainability into the design process. Although this case study provides feedback to improve CEE sustainability education at Georgia Tech, it also serves as an example for other programs interested in evaluating their curricula from a student perspective. [ABSTRACT FROM AUTHOR]

Construction operations generate significant air pollutant emissions, including carbon emissions and diesel exhaust emissions. Controlling operational efficiency is the most important strategy for reducing air pollutants emitted from construction operations. However, current practices to assess air pollutant emissions from construction operations tend to ignore the variability of the operational efficiency that results from different resource allotting and scheduling. In this context, this paper presents a methodology for incorporating the analysis of operational efficiency into quantifying the amount of exhaust emission from construction operations. Case studies are presented to examine how and to what extent planning decisions affect the amount of air pollutants emitted from construction operations and to identify the impact that possible alternatives have on the schedule and cost of projects. The findings of case studies indicate that considering environmental aspects in the planning stage could contribute to a project's increased integrated value, which includes schedule, cost, and environmental impact. [ABSTRACT FROM AUTHOR]

The engineers of the ancient Inca Empire cleverly used the resources of nature efficiently. Because of their unique awareness of nature, they were able to build durable structures that have lasted for more than 500 years. The structures they created reveal an exacting observation of the forces of nature and a honed ability to work in cooperation with those forces. This summation of the Inca storehouse structures in relationship to nature demonstrates that the relationship between construction and nature is powerful and can be used in a positive manner. Modern engineers can create more sustainable structures if they devote careful attention to nature. [ABSTRACT FROM AUTHOR]

Although prefabrication is becoming popular as an approach to conquer the chronic problems in construction, it has inherent issues related to inefficiencies in its production process. To address these production process related inefficiencies, lean production principles (LPP) can be applied. Hence, this paper aims to investigate the application of LPP to the precast concrete bridge beam production process (PCBBPP). The research collected data within three selected case studies by observing PCBBPP and interviewing executive-level professionals, to map the process, to identify conversion activities and their efficiency enhancing methods, and to record flow activities and their associate waste, waste causes, and elimination/minimization methods. The research analysed data by using code-based content analysis, and the findings are presented by using tables, matrices, and maps. The results revealed 103 activities associated with PCBBPP, of which 59 are conversion activities. Among 44 flow activities, 17 can be eliminated. The results also indicated several methods and techniques to eliminate/minimize flow activities and enhance the efficiency of PCBBPP conversion activities to enable implementation of LPP in prefabrication yards. By applying LPP to PCBBPP, several long-term benefits were revealed that contribute to sustainable construction. These results are useful for prefabrication companies and those who deal with sustainability issues. [ABSTRACT FROM AUTHOR]

Construction activities and the built environment have an enormous effect on the environment, human health, and the overall economy. Sustainable homebuilding in all three dimensions of economic, environmental, and social effects is attainable through practical innovations and technologies. However, the greatest barrier to the widespread application of sustainable homebuilding is the higher initial costs largely attributable to the learning curve of workers building with these practical innovations and technologies, and the added cost resulting from ill-defined construction processes. To address these challenges and reach the ideal of sustainable construction, this paper proposes the use of lean construction as a viable and effective strategy, in particular the lean tool kaizen. This paper uses several case studies to showcase the effect of lean on the triple bottom line of sustainability in modular homebuilding. Each case study highlights one dimension of sustainability. Lean construction resulted in a significant environmental effect by reducing material waste by 64%, a significant social effect by reducing or eliminating key safety hazards of excessive force, poor posture, and struck-by, and a significant economic effect by reducing production hours by 31%. Findings from this research will contribute to a better understanding of the effect of lean on homebuilding sustainability and will promote lean and safe building techniques in modular homebuilding. [ABSTRACT FROM AUTHOR]

The clean development mechanism (CDM), part of the Kyoto Protocol to combat rising carbon emissions, allows projects to proceed in developing countries in return for providing carbon credits to developed countries. The feasibility of CDM projects is commonly justified through a combination of sale of the end product and carbon credits, which have a financial value, generated through carbon emissions avoided. However, the carbon credits assumed or estimated at the feasibility stage may not be realized or achieved on project completion; the issuance of carbon credits may be less than that originally estimated, thereby affecting project feasibility. This paper examines the performance risk associated with the discrepancy between estimated and issued carbon credits. Data for 227 renewable energy projects, comprising hydroelectric and wind power of varying scale and in multiple countries, are examined in establishing the performance risk. The study found that overall, the hydroelectric power projects performed similarly on average to the wind-power projects for both large- and small-sized projects. Generally, estimated certified emission reductions (CERs) were not achieved. However, certain categories (type, scale, host country, monitoring period) performed better than others. The results will be of interest to investors, regulators, and researchers in such energy-carbon projects. [ABSTRACT FROM AUTHOR]

Global warming has grown into a significantly intense global issue, prompting all nations to exert various efforts to reduce their greenhouse gas emission, according to the United Nations Framework Convention on Climate Change (UNFCCC). The South Korean government is likewise working on reducing its greenhouse gas emission and, as part of its effort, it is currently promoting the Green-School Project. This project aims to create energy-saving schools by renovating deteriorated school buildings. In this study, CO2 emission reduction scenarios are sought by applying energy-saving techniques (ESTs) to educational facilities, and an optimal scenario is created by performing life cycle cost (LCC) analysis for each scenario. To this end, the amounts of energy consumption and CO2 emission reduction in two schools were evaluated using DesignBuilder simulation, based on 15 scenarios with combinations of four ESTs. LCC analysis was also performed. In terms of energy efficiency, CO2 emission reduction, and LCC analysis, the results showed that the most effective scenario is replacing the existing lighting with light-emitting diode (LED) lighting. The results also showed that there is a difference in energy efficiency, CO2 emission reduction, and LCC analysis based on the type and size of the school building. If the results of this study are considered in policy-making efforts by the Korea Ministry of Education, Science, and Technology, CO2 emission in the maintenance phase for South Korean educational facilities is expected to be reduced, and an optimal maintenance process using a limited budget will also be feasible. [ABSTRACT FROM AUTHOR]

Project firms currently have little incentive to incorporate environmental considerations into infrastructure development or management decisions beyond those that are either regulated or subject to public perception. This lack of incentive exists in part owing to the absence of: (1) a clear understanding of the connections between project ecological affects and how these damage firm/project assets; and (2) the ability to include the project ecological effects in operational decisions. In response, the concept of ecosystem service monetization is applied as a novel approach to capitalize on the relationship between industry and the natural environment. We present a framework for ecosystem service valuation that consists of four parts: (1) life cycle assessment (LCA) to quantify project ecosystem emissions; (2) fundamental biophysics and biochemistry to characterize the component processes of ecosystem services; (3) functional substitutability to assign a monetary value to such services; and (4) representation of ecosystem services value within international financial accounting norms. As a demonstration, the framework is applied to a project-level decision between alternative designs for a surface parking lot at Disney's new theme park in Shanghai, China. We conclude that the framework is able to inform project-level decisions, eventually leading to more sustainable management and development. Suggestions also are provided for future research to solidify the foundation, assess the robustness of the approach, and broaden the applicability of the framework. [ABSTRACT FROM AUTHOR]

The accumulation of CO2 emissions in the atmosphere is considered a major contributor to climate change. Consequently, it is essential to control the emissions generated by human activities to protect the environment for future generations. Many countries have set their own emission control targets to achieve by the middle of the century. In this context, it is important to quantify emissions from human activity and consider alternatives in order to reduce these emissions. This paper demonstrates a model for estimating life-cycle emissions resulting from an underground potable water-line project that could be used as a managerial decision support tool. The life cycle of the water pipeline is divided into different phases for the analysis. Different methods are used to estimate the emissions in each phase of the life cycle. The results indicate the life-cycle emissions from a demonstration 152.4-m (500-ft), 200-mm (8-in.)-diameter water pipeline at a representative 1.22-m (4-ft) depth range between 1,463.23 t and 1,524.98 t depending on the pipe material chosen. Four different pipe materials have been considered as alternatives in this research. The results indicate that molecular-oriented PVC (PVC-O) provides the best environmental savings compared to PVC, high-density polyethylene pipe (HDPE), and ductile iron in the demonstration of the potable water project. [ABSTRACT FROM AUTHOR]

The sustainability of a metro system is important not only to itself but also to local socioeconomic development. However, very few methodologies can be found for assessing the sustainability of metro systems, especially on the basis of emergy analysis. Demonstrating many advantages in sustainability assessment, emergy analysis has been utilized in assessing the sustainability of many objects including regions, industries, products, and projects. A methodology for assessing the sustainability of metro systems on the basis of emergy analysis is thus proposed in this paper. The proposed methodology aggregates three emergy indexes, namely, emergy yield ratio (EYR), environmental loading ratio (ELR), and the ratio of waste to total yield (RWY). Each of them has a specific sustainability meaning, whereas the proposed metro's emergy sustainability index (MESI) is equal to the ratio of EYR divided by the product of ELR and RWY. Then, the first stage of Nanjing Metro's Line one is studied as a case. It is believed that the proposed methodology is easily replicable and useful for design optimization of metro systems in the early stage. [ABSTRACT FROM AUTHOR]

It is difficult to quantitatively assess the impact of engine idling on fuel use and emissions of construction equipment because of a lack of sufficient data. This paper presents a methodology for evaluating the impact of idling on fuel use and carbon dioxide (CO2) emissions of diesel construction equipment. The results are based on field data collected from 34 items of equipment. Engine idle time may be quantified in terms of equipment operational efficiency (η), which is defined as the ratio of nonidle time to total equipment use time (nonidle time plus idle time). Using η and the ratio of idle to nonidle fuel use and CO2 emission rates (r), the percentage increase in the total quantities of fuel used and CO2 emitted (NE) were calculated for each item of equipment for values of η less than the maximum theoretical operational efficiency of 100%. Results showed that as η decreased (or idle time increased), NE increased. A mathematical model that uses η as a predictor variable was developed to estimate values of NE. This model accounted for approximately 85% (R2=0.85) of the variability in the data. Recommendations include using the model as a managerial performance measurement tool to assess idle restriction regulations and operational strategies of construction equipment. [ABSTRACT FROM AUTHOR]

This paper presents an overview of sustainable construction in civil engineering from the perspective of project management and sustainability assessment through indicators. It discusses the different approaches and requirements of sustainability assessment models that are based mostly on criteria and indicators, the needs that are deemed critical for the application of sustainability indicators in the civil engineering sector, and the challenges that remain to be overcome before they can be applied in general practice. The ultimate goal is indicators that allow comparison not only between alternatives but also between projects in regard to sustainability certification. [ABSTRACT FROM AUTHOR]

Previous sustainability engineering education studies have suggested the importance of problem-based learning, project-based learning, team-based learning, and interdisciplinary learning. Place-based learning, interacting with outdoors, and building sustainable communities are also important aspects of sustainability education, yet relatively little has been published on how to use these pedagogical approaches in engineering education. The goal of this paper was to illustrate the implementation of all these pedagogical approaches in a graduate-level sustainability engineering education class. Fink's taxonomy of significant learning and the University of Toledo's Outdoor Classroom Garden provided the framework for this implementation. Throughout the semester, sustainability engineering students worked toward an engineering solution for how to water the University of Toledo's outdoor classroom garden. They also estimated the life-cycle cost and environmental impacts of their proposed solutions. The garden project and the design of the course provided many different learning opportunities that might be absent in a traditional civil engineering class. [ABSTRACT FROM AUTHOR]

An existing multidisciplinary course on sustainable engineering in developing societies was expanded to include sustainability issues and challenges faced in the developed world. The new course consisted of independent modules on general background, sustainability concepts and tools, sustainable water and waste systems, sustainable energy systems, sustainable agricultural and food systems, and sustainable building systems. The course included a semester-long project experience conducted in interdisciplinary teams. Projects were sourced from local businesses and institutions or from organizations involved in international development. Course evaluation included an end-of-semester self-assessment by students and an analysis of project reports. Thirteen out of 18 students surveyed (72%) agreed that their ability to consider techno-economic, environmental, and social aspects of sustainability was improved as a result of the course. An improved student understanding of aspects of sustainability and its measures was also evident in student project reports. [ABSTRACT FROM AUTHOR]

The article explores whether a holistic perspective of sustainability that covers all necessary elements exists in the construction industry. Topics discussed include the development of a Leadership in Energy and Environmental Design (LEED) rating system and the assessment of sustainable buildings. Information is also presented on a new LEED Pilot Credit called the Prevention through Design.

Initial implementation of a road management system will typically face the challenge of a lack of time-series data for performance modeling. This paper presents one approach for developing initial performance prediction models that are required to support trade-off and optimization analyses in a road management system. The paper demonstrates that starting performance models can be formulated based on as little as 2 years’ network-level data on condition and traffic. The paper builds a locally calibrated pavement condition index and subsequently uses it for network-level strategic planning and programming of works. The paper demonstrates a method of extracting initial estimates of treatments’ effectiveness from the condition data. The case study is based on the Costa Rican national road network. The model uses commercial software to allocate resources and optimize decisions. Several investment strategies were tested to investigate the sustainability of the road network value over time. The results demonstrate that optimization improves road conditions in a sustainable manner, which in the long run releases funds for other necessities. [ABSTRACT FROM AUTHOR]

Anthropogenic releases of carbon dioxide are being studied with respect to the global carbon dioxide cycle. Concrete, the most used building material in the world, contributes to these releases significantly in the manufacturing of cement, both from energy use and from the calcination chemical process. The reverse process, carbonation, in which the hydrated cement reacts with carbon dioxide to form calcite, is being studied under many different circumstances for its potential to balance this release by sequestering carbon dioxide. This research focuses on other carbon dioxide sequestration species within concrete. It is hypothesized, and has been shown in some cases, that many other dissolved carbon dioxide complexes exist within the cement paste matrix, as they do in many aqueous-based systems and also that carbonate species other than calcite may exist. It is shown that carbon dioxide species, other than calcite, do exist in cement paste samples in amounts that are significant with respect to the stoichiometric potential for reversing the calcination process. [ABSTRACT FROM AUTHOR]

Environmental restoration is a matter of national concern. Decades of abuse by industry, agriculture, and the military have caused devastating contamination of the earth, air, and water. The Department of Energy alone will spend hundreds of billions of dollars on containment and restoration. It is imperative that restoration costs are minimized. Every dollar spent on restoration is a dollar that will not go toward research, a dollar that will not go to upgrade our nation’s infrastructure. The work presented here uses cost as a decision variable in restoration projects. Contaminated sites frequently vary from one point to another in type and level of contamination. In addition, a single piece of property may contain several distinct contaminated areas, each of which has characteristics unlike any of the other areas. Thus one should look at optimizing the selection of remediation technologies to address the variation. A methodology has been developed that will optimize the selection of remediation technologies based on cost. This methodology uses geostatistics and dynamic programming to break a site into discrete cells and then select the optimal sequence of remediation technologies. [ABSTRACT FROM AUTHOR]

This article focuses on the emerging shift to sustainable, clean and renewable energy sources and the challenges it posed to civil engineering management. It discusses the characteristics of infrastructure for a sustainable energy future. It also elaborates on the importance of a life-cycle perspective for planning, implementing and managing such new infrastructure. A summary of engineering management priorities for sustainable energy is given.

The most crucial architectural design stage is the early design phase, when most of the critical decisions are made. To address the significance of this stage, the design team is obliged to rapidly evaluate many design variations. The current research presents a framework to expedite this process, to assist architects early in the decision-making process. To create an effective methodology, the main criteria in the design of building envelopes (i.e., sustainability and energy consumption) were investigated while preserving the extendable nature of the proposed method. A full life cycle assessment (LCA), along with annual energy-consumption calculations for over a hundred exterior glazing system typologies, was performed. In the next step, a multiobjective optimization using Strength Pareto Evolutionary Algorithm (SPEA2) was utilized to make the LCA and energy-consumption data obtained from the previous step comparable for designers by providing a set of optimized data and comparing the distance of the design variations from Pareto's curve. The results will assist architects in mitigating the ecological footprint of their design more quickly and efficiently, specifically regarding material selection. [ABSTRACT FROM AUTHOR]

A major 2006 survey of US schools of architecture identified significant problems in the way earthquake engineering design was integrated into and taught in their curricula. More than 10 years later, this paper reviews several of the significant problems raised, and reports on new developments in three areas. First, after acknowledging the pivotal role of the design studio in architectural education, two models of teaching earthquake engineering by linking seismic design to design studio projects are reported. The success of the models is attributed to both short and intense tutoring sessions by external professional engineers, coupled with the use of seismic design rule-of-thumb software. The second area of progress has been the remedying of shortcomings in seismic design content and appropriate teaching resources. Finally, the paper focuses on the development and use of rule-of-thumb software. This empowers students to design and size the seismic-resistant structure their design projects require. Results from student surveys in several countries suggest the software is appropriate for its users and it contributes positively to the seismic design education of architects. The paper concludes that an effective approach to teaching seismic design in a school of architecture necessitates a certain minimum content being conveyed to the students, followed by application of this material to one or more of their studio design projects. The inherent structural complexity of these projects requires tutorial advice from professional engineers that can be limited and should then be taken to another level of detail by the use of rule-of-thumb software. [ABSTRACT FROM AUTHOR]