Christopher W. Swan

Lightweight Fly Ash-Plastic Aggregates in Concrete

The potential of using a synthetic lightweight aggregate (SLA) in concrete is examined. The aggregates are manufactured through thermal processing using plastic to encapsulate and bind fly ash particles. Nominal maximum-size aggregates of 9.5 mm were produced with fly ash contents of 0 percent, 35 percent, and 80 percent by total mass of the aggregate. The plastic used was high-density polyethylene, and the fly ash had a carbon content of 12 percent. An expanded clay lightweight aggregate and a normal-weight aggregate were used as comparison. Gradation, specific gravity, and absorption capacity are reported for the aggregates. Five batches of concrete were made with the different coarse aggregate types. Volume fractions of cement, water, fine aggregates, and coarse aggregates were kept the same for comparative purposes. Mechanical properties of the concrete determined included density, compressive strength, elastic modulus, splitting tensile strength, fracture toughness, and fracture energy. Salt-scaling resistance, a concrete durability property, was also examined. Compressive and tensile strengths were lower for the synthetic aggregates than for the normal-weight and expanded clay lightweight aggregates; however, comparable fracture properties were obtained. Relatively low compressive modulus of elasticity was found for concretes with the SLAs, although high ductility was also obtained. As fly ash content of the SLAs increased, all properties of the concrete were improved. Excellent salt-scaling resistance was obtained with the SLA containing 80 percent fly ash.

Assessing students’ motivation to engage in sustainable engineering

Purpose – The purpose of this study was to design an assessment instrument to evaluate students’ attitudes toward sustainable engineering (SE). Factors that impact SE beliefs could then be explored. Design/methodology/approach – Using the definition of sustainability from the Brundtland report and expectancy value theory, students’ sentiment toward SE was evaluated using items to assess SE self-efficacy, SE value and SE affect. The survey was distributed at three diverse universities with 515 responses from students ranging from first year through graduate studies in a variety of engineering majors. The survey instrument was validated using principal components analysis, and internal reliability was established via high Cronbach’s alpha for each construct. Findings – Participation in more experiential, enriching learning experiences correlated to higher SE self-efficacy, value and affect. Extracurricular club involvement correlated with a lower self-efficacy but high SE value. Students who had participate...

Cambridge Handbook of Engineering Education Research: Community Engagement in Engineering Education as a Way to Increase Inclusiveness

Introduction There has been a recent surge in community engagement (CE) efforts in engineering education. These efforts have involved a spectrum of academic avenues – from curricular to co-curricular to extracurricular – that cover community-based projects in local to global settings. For example, many CE experiences can be embedded within courses in the traditional pedagogical form of service-learning, although in many cases CE activities are implemented and/or facilitated by nonacademic organizations, such as Engineers Without Borders (EWB). These activities continue to undergo increasing levels of design, management, and assessment, the latter driven, in part, by the outcomes assessment requirements for ABET engineering program accreditation in the United States, but also because of apparent positive impacts to student participants. Previous studies indicate that the knowledge and skills gained by the students are at least on par with gains from traditional education models (e.g., see Bielefeldt, Paterson, & Swan, 2010). Additional attention also is being focused increasingly on the potential impacts of CE on student attitudes and identity (Paterson, Swan, & Guzak, 2012) as well as long-term impacts on students as they enter the professional ranks (Canney & Bielefeldt, 2012). It is in these areas that differences in the influence of CE may appear more profound, yet small numbers of student participants in various programs and a lack of coordinated assessment efforts provide limited evidence that such results exist. This chapter highlights the development of CE in engineering education and possible research endeavors that can be taken to shed new light on its potential impact.

Sustainable Engineering Assessment Using Rubric-Based Analysis of Challenge Question Responses

AbstractA method to evaluate students’ application of sustainability principles into engineering design and problem solving was developed. Students were presented with two challenge questions that each posed a scenario. Students responded to one question and their answers were scored using a rubric that combined both analytic and holistic scoring criteria to account for sustainability principles. The rubric was iteratively developed and met standard measures of reliability and validity. Based on responses from primarily civil and environmental engineering students at three institutions, it was found that male students, seniors, and participants in many diverse learning activities (extracurricular service, internships, undergraduate research, and engineering design courses) achieved higher rubric scores. Scores on the challenge questions did not correlate to students’ interests in sustainable engineering, which were measured using a Likert-based survey. A challenge-question approach to formative assessment...

Macroethics instruction in co-curricular settings: The development and results of a national survey

Ethical awareness and decision-making are important skills for graduating engineers transitioning into professional practice and for engineering education accreditation. Ethics instruction can target microethics which focuses on individual projects and topics such as safety, and macroethics which covers larger ethical topics in the field of engineering such as sustainability. While much research has addressed microethical concerns, fewer studies have addressed macroethicial issues. Ethics instruction takes place in a wide variety of settings, both curricular in for-credit classes and co-curricular settings such as clubs and societies. The present work-in-progress paper presents a National Science Foundation supported investigation into macroethics education in co-curricular settings that gathered information via a survey of instructors and mentors of these activities. Preliminary results from the on-going survey are presented, including the settings for co-curricular macroethics instruction and the ethics topics that are discussed. Also, assessment methods used to determine outcomes will be discussed.

Characteristics of a Coal Fly Ash Subjected to Additional Processing

This paper presents the results of a study of the physical and environmental properties of pre- and post-processed fly ashes (termed Raw and Processed fly ashes, respectively). The ashes were collected from a coal-fired power plant in the northeastern U.S. which utilizes a carbon burn-out unit (CBO) to prepare the fly ash for concrete and other construction applications. Measured physical properties included carbon contents via loss-on-ignition (LOI), specific gravities, gradation analyses, and scanning electron microscopy (SEM). In addition, total and leachable concentrations of lead, selenium, and arsenic were determined. Leachable concentrations were determined for leaching solution pHs varying between 1.5 and 11.5. When compared to Processed fly ash, Raw fly ashes had an expectedly higher LOI (approximately 2% versus 6% carbon content, respectively) and lower specific gravity (2.37 versus 2.18, respectively). Although the total metal content of the fly ashes was similar, leachable metal concentrations were notably higher for the Processed fly ash over the full range of leaching solution pHs evaluated. The test results indicate that the CBO process, at times necessary to create usable fly ash, can result in fly ashes with notably altered physiochemical properties that lead to higher leachable contaminant concentrations.

The Use of Term Paper Projects to Learn Geo-Engineering

Over the last few years, students taking the Introduction to Geotechnical Engineering course at Tufts University have performed term projects where they develop written reports and oral presentations on various topics in geo-engineering. This paper presents how these efforts have enhanced the learning experience of the course. Specifically, the paper presents how the project is integrated into the course, assessment methods used for grading, and the value such projects have had on student learning, based on post-course evaluations. A shortened example of a student’s work is presented. It can be concluded that the project allows not only a deeper appreciation of geo-engineering by the students, but also provides an avenue for students to practice their communication skills; one of the ABET Criterion 3 outcomes.