Carbon nano-tube as water reducer in CDOT Class E 12 hr concrete mix

To address maintenance and durability issues for concrete pavement, the City and County of Denver explored the use of carbon nano-tube admixtures. This research documents the hardened and fresh properties of two mix designs that use carbon nano-tube admixture as a water reducer. The authors performed compressive strength, slump and air-entrainment tests. Results indicate that the 3 gallon-per-yard (GPY) (14.85 l/m3) mix provides both the highest slump and the highest compressive strength, while meeting the air-entrainment specifications for Colorado Department of Transportation (CDOT) Class E 12 h Concrete Mix. While additional testing is recommended to evaluate long-term maintenance impacts, initial results are promising and suggest that adoption of a 3 GPY (14.85 l/m3) mix may be a viable alternative for CDOT. The contribution of this research is to document preliminary laboratory and in-situ testing of carbon nano-tube admixtures in concrete pavement mix design. Keywords: Carbon nano-tubes, Admixture, Concrete mix design, Concrete pavemen

Implementing a collaboration activity in construction engineering education

Collaboration skills are increasingly necessary in today’s construction workforce. However, classroom activities that incorporate collaboration skills, ones involving interactive work among individuals towards a common goal, are underrepresented in many construction classes. This research documents and illuminates implementation of a team activity where groups of interdisciplinary students were asked to build a structure using the provided (paper and tape) resources with the objectives to create a structure that stands at least 4” tall and supports as much weight (under textbook loading) as possible. Two rounds of activities were performed with differing levels of role definition provided to the students. Team interactions and performance were recorded, along with student self-assessments, and reporter observation. The implementation of this collaboration activity continues to provide valuable lessons, which informs the integration and assessment of collaboration activities in construction education.Non UBCUnreviewedFacultyOthe

Minimizing greenhouse gas emissions and water consumption of existing buildings

Buildings are responsible for 38% of all carbon emissions and 14% of water consumption in the United States. These negative environmental impacts can significantly be reduced by implementing green upgrade measures such as energy-efficient lighting and HVAC systems, motion sensors, photovoltaic systems, and water-saving plumbing fixtures. Building owners in the public and private sectors often search for an optimal set of upgrade measures that is capable of minimizing the negative environmental impacts of their buildings. This paper presents the development of an optimization model that is capable of identifying optimal selection of building upgrade measures to minimize greenhouse gas emission and water consumption of existing buildings while complying with limited upgrade budgets. The model is developed in four main development steps: metrics identification step that quantifies greenhouse gas emissions and water consumption of existing buildings; model formulation step that formulates the model decision variables, objective function, and constraints; implementation step that executes the model computations and specifies the model input and output data; and validation step that evaluates the model performance using a case study of an existing building. The results of the model illustrate its new and unique capabilities in providing detailed results, which include specifications for the recommended upgrade measures, their location in the building, and required upgrade cost to minimize greenhouse gas emissions and water consumption of existing buildings.Non UBCUnreviewedFacultyOthe

Energy Star windows' performance and orientation

In 2012 and 2013, ten building product categories were eligible for United States ENERGY STAR Federal Tax Credits. High performance windows that meet certain energy efficiency criteria are one of the qualifying products. The ENERGY STAR Tax Credit program sets U-factor and Solar Heat Gain Coefficient (SHGC) standards for these windows according to four climate zones. Research demonstrates that buildings with well-designed and constructed fenestration systems can lower requirements for heating, cooling and lighting during operation. However, previous research and energy modeling also demonstrates that, in addition to energy efficiency characteristics, orientation impacts the energy performance of windows. The ENERGY STAR tax program makes no distinction regarding window orientation or placement when evaluating tax credit eligibility. This research studies the potential impact of orientation on performance for qualifying ENERGY STAR window products. Using TRNSYS energy modeling comparisons, findings suggest that the performance of qualifying windows may vary up to 14 percent for different orientations depending on climate zone.Non UBCUnreviewedFacultyOthe