Assistant Professor in Construction Management Dr. Amos Darko was ranked in the top 0.05% of scholars in Green Build based on the comprehensive scope and impact of his work. This achievement speaks to the expertise Dr. Darko has in his field, and the value his work brings to CBE. Congratulations to Dr. Darko on this achievement! See more about Dr. Darko’s work here.
Research Theme: Green Building & Infrastructure
Methods and scholarship such as carbon sequestration and green infrastructure, in the built environment, at the scales of the building to the region
Evaluating carbonation resistance and microstructural behaviors of calcium sulfoaluminate cement concrete incorporating fly ash and limestone powder
Mohammed, T., Torres, A., Aguayo, F., & Okechi, I. K. (2024). Evaluating carbonation resistance and microstructural behaviors of calcium sulfoaluminate cement concrete incorporating fly ash and limestone powder. Construction & Building Materials, 442, 137551-. https://doi.org/10.1016/j.conbuildmat.2024.137551
Abstract
This study investigates the effects of accelerated carbonation on calcium sulfoaluminate (CSA) cement concrete, focusing on mixtures enhanced with 20 % fly ash (FA), 20 % remediated fly ash (RF), 15 % limestone powder (LP), and a combination of 20 % FA with 15 % LP (35 %). The study further evaluates the mechanical properties including compressive strength, splitting tensile strength, elastic modulus, along with drying shrinkage and bulk resistivity. To delve into the microstructural characteristics of moist curing versus carbonation exposure on the CSA cement system, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were employed, particularly analyzing phase assemblage changes. The results show that the addition of FA reduced the carbonation depth in concrete mixtures over time (105 days). However, LP and the combination of FA and LP presented mixed effects. The microstructural analysis highlighted ettringite as the predominant phase in samples moist cured for 3 days. In contrast, carbonation-cured samples were characterized by different calcium carbonate (CaCO3) polymorphs alongside aluminum hydroxide (Al(OH)3) and residual ye'elimite, with the formation of low-pH carbonic acid facilitating the conversion of ettringite into CaCO3. This study highlights the impact of different SCMs on the durability and microstructural characteristics of CSA cement concrete, underscoring the interplay between curing methods, effects of SCM, and carbonation processes.
Keywords
Calcium sulfoaluminate cement (CSA); Carbonation; Limestone powder; Fly Ash; Microstructural analysis
Life Cycle Lab receives EPA award for $10M, 5-year collaborative research project
The University of Washington’s Life Cycle Lab, with Lab Director and Professor of Architecture Kate Simonen, has been awarded a $10 million, 5-year collaborative research project from the Environmental Protection Agency (EPA). The project is entitled “Validating and Extending Research and Education for Life Cycle Assessment (VERE-LCA)” and the work will be done in partnership with collaborators from Howard University, Pacific Northwest National Laboratory, and CBE UC Berkley. Read more about the EPA funding and other projects that were awarded…
Measures, benefits, and challenges to retrofitting existing buildings to net zero carbon: A comprehensive review
Weerasinghe, L. N. K., Darko, A., Chan, A. P. C., Blay, K. B., & Edwards, D. J. (2024). Measures, benefits, and challenges to retrofitting existing buildings to net zero carbon: A comprehensive review. Journal of Building Engineering, 94, 109998-. https://doi.org/10.1016/j.jobe.2024.109998
Abstract
Net zero carbon (NZC) retrofitting of existing buildings contributes to improving occupants' well-being, addressing carbon footprint directly and is key to solving the global climate crisis. However, a fragmented NZC retrofit knowledge base exists and this challenges the ability to effectively implement NZC practices. This study, therefore, integratively and comprehensively reviews existing literature on NZC retrofitting of existing buildings and identifies research gaps to provide future research directions. Bibliometric analysis was conducted using 1544 relevant articles identified from Scopus. Moreover, based on 125 carefully selected articles, a further qualitative analysis was also conducted. Results indicated a gradual increase in interest in NZC retrofitting research since 2007. Emergent findings reveal that the UK, Italy, US, China and Spain are the top five countries in this research field and that in NZC retrofitting, energy is mostly prioritised. Key research themes include NZC retrofitting benefits, challenges and measures. Based on identified knowledge gaps, future research directions are proposed to include: (1) analysis of NZC retrofitting measures based on building types and climate conditions; (2) integration of NZC retrofitting measures; (3) effects of occupants' health, well-being and satisfaction on retrofitting; (4) integration of modern technology; (5) quantitative study on benefits; and (6) dealing with objections to NZC retrofitting. Emergent findings generate an in-depth understanding of the NZC retrofitting field and provide a useful milestone reference for future NZC retrofitting practice and improvement in the industry.
Assistant Professor Amos Darko wins 2023 Sustainability Young Investigator Award
Dr. Amos Darko, assistant professor in Construction Management has won the competitive international sustainability award, the 2o23 Sustainability Young Investigator Award. The award is in recognition of excellence in the field of sustainability and sustainable development. Congratulations to Dr. Darko on this achievement!
Awareness, adoption readiness and challenges of railway 4.0 technologies in a developing economy
Awodele, I. A., Mewomo, M. C., Municio, A. M. G., Chan, A. P. C., Darko, A., Taiwo, R., Olatunde, N. A., Eze, E. C., & Awodele, O. A. (2024). Awareness, adoption readiness and challenges of railway 4.0 technologies in a developing economy. Heliyon, 10(4), e25934–e25934. https://doi.org/10.1016/j.heliyon.2024.e25934
Abstract
The railway industry has witnessed increasing adoption of digital technologies, known as Railway 4.0, that is revolutionizing operations, infrastructure, and transportation systems. However, developing countries face challenges in keeping pace with these technological advancements. With limited research on Railway 4.0 adoption in developing countries, this study was motivated to investigate the awareness, readiness, and challenges faced by railway professionals towards implementing Railway 4.0 technologies. The aim was to assess the level of awareness and preparedness and identify the key challenges influencing Railway 4.0 adoption in Nigeria's railway construction industry. A questionnaire survey (was distributed to professionals in the railway construction sector to gather their perspectives on awareness of, preparation for, and challenges associated with the use of Railway 4.0 technologies. The results revealed that awareness of Railway 4.0 technologies was moderate, while readiness was low among the professionals. Using exploratory factor analysis, 10 underlying challenge constructs were identified including lack of technical know-how, resistance to change, infrastructure limitations, and uncertainty about benefits, amongst others. Partial Least Square Structural Equation Modelling (PLS-SEM) confirmed these constructs, with reliability and availability, lack of technical know-how, lack of training and resources, and uncertainties in benefit and gains having significant influence on awareness and readiness. The study concludes that focused efforts in training, infrastructure improvement, supportive policies, and communicating the advantages of Railway 4.0 are critical to drive adoption in Nigeria and other developing economies. The findings provide insights into tailoring Railway 4.0 implementation strategies for developing contexts.
Keywords
Railway 4.0; Awareness; Readiness; Challenges; Technologies
Driving factors for the adoption of green finance in green building for sustainable development in developing countries: The case of Ghana
Debrah, C., , , , , & (2024). Driving factors for the adoption of green finance in green building for sustainable development in developing countries: The case of Ghana. Sustainable Development, https://doi.org/10.1002/sd.3022
Abstract
While there are many motivating factors for green finance (GF) implementation, a comprehensive taxonomy of these variables is lacking in the literature, especially for green buildings (GBs). This study aims to analyze the criticality and interdependence of GF-in-GB's driving factors. This study develops a valid set of factors to justify the interrelationships among the drivers. The drivers of GF-in-GB are qualitative in nature, and uncertainties exist among them due to linguistic preferences. This study applies the fuzzy Delphi method to validate eight drivers under uncertainties. Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL) with qualitative information is used to determine the interrelationships among the drivers. The drivers were grouped under two categories: prominent drivers and cause-effect drivers. The findings revealed that “increased awareness of GF models in GB” and “preferential capital requirements for low-carbon assets” are the top two most prominent/important drivers of GF-in-GB. In Ghana, the top three cause group drivers are “climate commitment,” “improved access to and lower cost of capital,” and “favorable macroeconomic conditions and investment returns.” Drivers with the highest prominence values have the potential to affect and/or be affected by other drivers; therefore, managers and policymakers should prioritize promoting or pursuing these drivers in the short term. On the other hand, it is important to pay more than equal attention to the drivers with the highest net cause values because they have the largest long-term impact on the entire system. The theoretical and practical implications of the study are discussed, enhancing understanding and decision-making in GF-in-GB.
Driving factors for the adoption of green finance in green building for sustainable development in developing countries: The case of Ghana
Debrah, C., Chan, A. P. C., Darko, A., Ries, R. J., Ohene, E., & Tetteh, M. O. (2024). Driving factors for the adoption of green finance in green building for sustainable development in developing countries: The case of Ghana. Sustainable Development., 1–22. https://doi.org/10.1002/sd.3022
Abstract
While there are many motivating factors for green finance (GF) implementation, a comprehensive taxonomy of these variables is lacking in the literature, especially for green buildings (GBs). This study aims to analyze the criticality and interdependence of GF‐in‐GB's driving factors. This study develops a valid set of factors to justify the interrelationships among the drivers. The drivers of GF‐in‐GB are qualitative in nature, and uncertainties exist among them due to linguistic preferences. This study applies the fuzzy Delphi method to validate eight drivers under uncertainties. Fuzzy Decision‐Making Trial and Evaluation Laboratory (FDEMATEL) with qualitative information is used to determine the interrelationships among the drivers. The drivers were grouped under two categories: prominent drivers and cause‐effect drivers. The findings revealed that “increased awareness of GF models in GB” and “preferential capital requirements for low‐carbon assets” are the top two most prominent/important drivers of GF‐in‐GB. In Ghana, the top three cause group drivers are “climate commitment,” “improved access to and lower cost of capital,” and “favorable macroeconomic conditions and investment returns.” Drivers with the highest prominence values have the potential to affect and/or be affected by other drivers; therefore, managers and policymakers should prioritize promoting or pursuing these drivers in the short term. On the other hand, it is important to pay more than equal attention to the drivers with the highest net cause values because they have the largest long‐term impact on the entire system. The theoretical and practical implications of the study are discussed, enhancing understanding and decision‐making in GF‐in‐GB.
Keywords
fuzzy Delphi method; fuzzy DEMATEL; green building; green finance; sustainable development
Challenges to energy retrofitting of existing office buildings in high-rise high-density cities: The case of Hong Kong
Linyan Chen, Amos Darko, Mayowa I. Adegoriola, Albert P.C. Chan, Yang Yang, Mershack O. Tetteh, “Challenges to energy retrofitting of existing office buildings in high-rise high-density cities: The case of Hong Kong,” Energy and Buildings, Volume 312, 2024, 114220, ISSN 0378-7788, https://doi.org/10.1016/j.enbuild.2024.114220.
Abstract
Achieving carbon neutrality by 2050 has become a global goal, sparking concerns regarding energy consumption and carbon emissions in building operations. Office buildings in high-rise high-density cities serve as central business districts, contributing significantly to the city’s economic activity and consuming a lot of energy. The process of retrofitting existing office buildings for energy efficiency in high-rise high-density cities tends to be challenging. However, there is a lack of comprehensive understanding of the challenges involved in office buildings’ energy retrofitting, as they have not been thoroughly explored. This study aims to investigate the challenges to the existing office building energy retrofitting (EOBER) in high-rise high-density cities with real cases in Hong Kong. Initially, a systematic literature review was undertaken to identify 49 potential EOBER challenges and categorized into seven groups: technical, financial, institutional, social, environmental, regulatory, and other categories. Afterward, 23 EOBER challenges were identified through 24 semi-structured interviews with 36 real office building energy retrofitting cases in Hong Kong. Moreover, these challenges were quantified by the Z-numbers-based Delphi survey and analysis. Results show that regulatory challenges are the primary challenges, followed by financial challenges. The lack of government incentives, policies, legislation and regulations significantly hinders practitioners’ ability to engage in energy retrofitting initiatives. The long payback period of building energy retrofitting poses a critical financial concern for practitioners embracing such initiatives. In the end, this research proposed integrated strategies to tackle these challenges and increase building energy efficiency, including launching financial and regulatory incentives, shortening the interval for mandatory energy audits, disseminating knowledge, and diversifying finance channels of building energy retrofitting. The findings contribute to the body of knowledge by employing systems thinking to identify and evaluate EOBER challenges in high-rise high-density cities through empirical methodologies. Moreover, this study provides valuable references for practitioners in navigating these challenges and minimizing risks associated with the retrofitting process.
Effects of Hydrothermal Modification on The Mechanical Properties of Red Alder (Alnus Rubra) Native to The Pacific Northwest
Muiruri, K., Ganguly, I., McPeters, K., & Alonzo, B. (2024). Effects of Hydrothermal Modification on The Mechanical Properties of Red Alder (Alnus Rubra) Native to The Pacific Northwest. The 2024 International ConCave Ph.D. Symposium: Divergence in Architectural Research. Georgia Tech, Atlanta, April 4-5.