• Energy Research

Abstract Heated pavement systems (HPS) offer an attractive alternative to the cumbersome process of removing ice and snow from airport pavements using traditional snow removal systems. Although snow and ice removing efficiency and economic benefits of HPS have been assessed by previous studies, their environmental impact is not well known. Airport facilities offering public or private services need to evaluate the energy consumption and global warming potential of different types of snow and ice removal systems. Energy usage and emissions from the operations of hydronic heated pavement system using geothermal energy (HHPS-G), hydronic HPS using natural gas furnace (HHPS-NG), electrically heated pavement system (EHPS), and traditional snow and ice removal system (TSRS) are estimated and compared in this study using a hybrid life cycle assessment (LCA). Based on the system models assessed in this study, HPS application in the apron area seems to be a viable option from an energy or environmental perspective to achieve ice/snow free pavement surfaces without using mechanical or chemical methods. TSRS methods typically require more energy and they produce more greenhouse gas (GHG) emissions compared to HPS during the operation phase, under the conditions and assumptions considered in this study. Also, HPS operations require less energy and have less GHG emissions during a snow event with a smaller snowfall rate and a larger snow duration.

Abstract Wind energy has played an increasingly vital role in renewable power generation, driving the need for more cost-effective wind energy solutions. Health monitoring of turbines could provide a variety of economic and other benefits to aid in wind growth. A number of commercial and research health monitoring systems have been implemented for wind turbines. This paper surveys these systems, providing an analysis of the current state of turbine health monitoring and the challenges associated with monitoring each of the major turbine components. This paper also contextualizes the survey with the various potential benefits of health monitoring for turbines.

Abstract Airports are moving toward utilizing clean energy technologies along with the implementation of practices that reduce local emissions. This includes replacing fossil fuel-based with electricity-based operations. These changes would significantly impact the energy demand profile of airports. Electrically-conductive concrete (ECON) is currently a focus of heated pavement design for replacing conventional snow removal practices. ECON heated pavement systems (HPSs) use electricity to heat the pavement surface. Since experimental studies are resource intensive and ECON HPS performance depends on weather conditions, developing a field data-validated numerical model enables its long term energy performance evaluation. In this research, a finite element (FE) model is developed and experimentally-validated using two proposed model-updating methods for full-scale ECON HPS test slabs constructed at Des Moines International Airport (DSM) in Iowa. The model predicts energy demands and average surface temperatures within 2% and 13% respectively. The estimated power demand ranges from 325 to 460 W/m2 for different weather conditions. The results of this study provide a validated tool that can be used to evaluate the energy demand of ECON HPS. Studying the energy demand of ECON HPS opens the way for developing control strategies to optimize its energy use which will contribute to developing sustainable communities.

AbstractSustainable use of biomass as a renewable source of energy can be an alternative solution to the cost of fossil-based energy and global warming. Production of biofuel from plant biomass results not only in bio-based energy, but also in coproducts containing lignin, modified lignin, and lignin derivatives. This paper discusses the moisture susceptibility of subgrade soil stabilized by bio-based energy coproducts containing lignin, with the aim of establishing a new application for bio-based energy coproducts in soil stabilization. An experimental test program was conducted to compare the moisture susceptibility of lignin coproduct-treated soils and traditional fly ash stabilizer-treated soil samples. Additive combinations were also evaluated. There were two types of laboratory tests for moisture susceptibility evaluation: (1) unconfined compression strength (UCS) tests after “dry” and “wet” conditioning, and (2) visual observation of soaked specimens. Results indicate that the biofuel coproducts ha...

Electrically conductive concrete (ECON) heated pavement system (HPS) is a newly developed clean technology to reduce the use of polluting chemicals for removal of snow and ice. This technology requires further comprehensive studies for achieving an energy-efficient design. To construct an energy-efficient system, ECON HPS design includes determining the most appropriate configuration of electrodes embedded in the ECON layer. The spacing, shape and dimensions of these electrodes are important design factors impacting the thermal and energy performance of the system. While field tests are resource-intensive, the use of numerical modeling can complement such experimental tests to provide a better overall understanding of the technology’s behavior. In this paper, the thermal and energy performance of ECON HPS is investigated through considering various system configuration designs, with an experimentally validated finite element model. A performance index is defined for comparing both thermal and energy performance of the configurations to obtain an energy-efficient design. The results indicate that a configuration with six circular electrodes at 100 cm spacing exhibited the best performance index and the highest energy efficiency. Since a test section with higher performance index would be capable of achieving a higher average surface temperature for the same energy input, such a section would have higher efficiency compared to other sections evaluated. This analysis results in narrowing down the ECON HPS’s configuration design options before performing experimental tests.

Abstract Traditional methods of removing snow/ice from pavements involve application of deicing salts and mechanical removal that carry environmental concerns. In this study, the feasibility of applying carbon fiber-based electrically conductive concrete (ECON) in heated pavement systems (HPS) as an alternative to traditional methods was investigated. Optimum carbon fiber dosage to achieve desirable electrical conductivity and avoid excessive fiber use was determined by studying carbon fiber percolation in different cementitious composites. System design was evaluated by finite element (FE) analysis. Heating performance in terms of energy consumption regime was studied by quasi-long-term (460-day) experimental study using a prototype ECON slab. Percolation transition zone of carbon fiber in paste, mortar, and concrete were respectively 0.25–1% (Vol.), 0.6–1% (Vol.), and 0.5–0.75% (Vol.). Optimum fiber dosage in ECON with respect to conductivity was 0.75%, resulting in volume conductivity of 1.86 × 10−2 (S/cm) at 28 days and 1.22 × 10−2(S/cm) at 460 days of age. Electrical-energy-to-heat-energy conversion efficiency decreased from 66% at 28 days to 50% at 460-day age. The results showed that the studied technology could be effectively applied for ice/snow melting on pavement surfaces and provide a feasible alternative to traditional methods if the ECON mixing proportions and system configurations are made with necessary precautions.

By 2050, approximately 43 million tons of wind-turbine blade (WTB) waste materials will have accumulated, emphasizing the critical importance of effective waste management strategies for WTBs at the end of their life cycle to ensure sustainability. Comparing current WTB waste management methods, reuse emerges as a highly-sustainable method that can also serve as a sustainable solution to environmental challenges, including global warming and natural resource depletion associated with civil engineering activities. This paper presents a comprehensive review of sustainable solutions for reusing WTB waste materials in civil engineering applications. Repurposing WTB waste materials as structural elements in housing, urban furniture, recreational facilities, and slow-traffic infrastructure can be a viable option. WTB waste can also be utilized in powder, fiber, and aggregate forms as an eco-friendly material for construction and pavement (e.g., mortar, concrete, asphalt) to replace cement and natural resource aggregates while meeting necessary strength and performance standards. Through a detailed analysis of reusing WTB waste materials, economic and environmental challenges are also discussed. According to the findings, the properties of mortar, concrete, and asphalt can be affected by the type, shape, and content of fibers, polymers, and impurities present in the blades, as well as the cutting direction. Furthermore, while reuse is considered a sustainable end-of-life (EoL) option for WTB waste management from both economic and environmental perspectives, further research is required to fully understand the environmental consequences of this method.

Lignin is considered as nature's most abundant aromatic polymer co-generated during papermaking and biomass fractionation. There are different types of lignins depending on the source (hardwood, softwood, annual crops, etc.) and recovery process. Recently, an emerging class of lignin products, namely sulphur-free lignins, from biomass conversion processes, solvent pulping and soda pulping, have generated interesting new applications owing to their versatility. As the renewable energy industry is expanding into developing the next generation of biofuels based on cellulosic biomass (e.g. corn stover, forest products waste, switch grass), abundant supply of sulphur-free lignin will become available as co-products for which value-added engineering applications are being sought. This paper discusses the potential for utilising lignin-containing biofuel co-products for stabilisation of geo-foundation beneath road pavements. Laboratory test results indicate that the biofuel co-products were effective in stabilis...

Sustainability has gained as much importance as management in business. Sustainable pavement development as a business practice should involve making evaluations according to the triple bottom line in the pavement life-cycle. Despite the current approaches to evaluating the social as well as economic and environmental feasibility of pavement projects (involving highway and airport infrastructure), there has recently been a lack of consensus on a methodology to guarantee sustainability upon assessment and analysis during the pavement life-cycle. As sustainability is a complex issue, this study intends to further explore sustainability and elaborate on its meaning. The second step involves a general depiction of the major sustainability appraisal tools, namely cost-benefit analysis, life-cycle cost analysis, life-cycle assessment, multi-criteria decision-making, environmental impact assessment and social life-cycle assessment, and an explanation of their cons and pros. Subsequently, the article addresses the application of an organized methodology to highlight the main factors or concepts that should be applied in sustainable pavement development and, more specifically, in sustainable pavement management. In the final step, research recommendations toward sustainability are given. This study is aimed to assist decision-makers in pavement management to plan sustainability frameworks in accordance with probable boundaries and restrictions.