Mousavinezhad, S., Toledo, W. K., Newtson, C. M., & Aguayo, F. (2024). Rapid Assessment of Sulfate Resistance in Mortar and Concrete. Materials, 17(19), 4678-. https://doi.org/10.3390/ma17194678
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Abstract
Extensive research has been conducted on the sulfate attack of concrete structures; however, the need to adopt the use of more sustainable materials is driving a need for a quicker test method to assess sulfate resistance. This work presents accelerated methods that can reduce the time required for assessing the sulfate resistance of mixtures by 70%. Class F fly ash has historically been used in concrete mixtures to improve sulfate resistance. However, environmental considerations and the evolving energy industry have decreased its availability, requiring the identification of economically viable and environmentally friendly alternatives to fly ash. Another challenge in addressing sulfate attack durability issues in concrete is that the standard sulfate attack test (ASTM C1012) is time-consuming and designed for only standard mortars (not concrete mixtures). To expedite the testing process, accelerated testing methods for both mortar and concrete mixtures were adopted from previous work to further the development of the accelerated tests and to assess the feasibility of testing the sulfate resistance of mortar and concrete mixtures rapidly. This study also established criteria for interpreting sulfate resistance for each of the test methods used in this work. A total of 14 mortar mixtures and four concrete mixtures using two types of Portland cement (Type I and Type I/II) and various supplementary cementitious materials (SCMs) were evaluated in this study. The accelerated testing methods significantly reduced the evaluation time from 12 months to 21 days for mortar mixtures and from 6 months to 56 days for concrete mixtures. The proposed interpretation method for mortar accelerated test results showed acceptable consistency with the ACI 318-19 interpretations for ASTM C1012 results. The interpretation methods proposed for the two concrete sulfate attack tests demonstrated excellent consistency with the ASTM C1012 results from mortar mixtures with the same cementitious materials combinations. Metakaolin was shown to improve sulfate resistance for both mortar and concrete mixtures, while silica fume and natural pozzolan had a limited impact. Using 15% metakaolin in mortar or concrete mixtures with Type I/II cement provided the best sulfate resistance.
Keywords
accelerated test method; concrete; metakaolin; mortar; natural pozzolan; sulfate attack
Dr. Carrie Sturts Dossick, Associate Dean for Research, and Professor in the department of Construction Management has been featured on the Building Innovation: The Podcast. The podcast episode is Season 2, Episode 1, and is part one of the NBIMS-US™ Series, and discusses the new module for Project BIM Requirements. Listen to the Podcast here: https://www.nibs.org/building-innovation-podcast
The Integrated Design Lab has released their 2023-2o24 Annual Report, available here. The Integrated Design Lab is lead by Christopher Meek and Heather Burpee. Christopher Meek is a Professor in the CBE Department of Architecture, and Director of the Integrated Design Lab. Heather Burpee is a Research Professor in the CBE Department of Architecture, and Director of Education and Outreach for the Integrated Design Lab.
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
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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
PCAD archives a range of information on the buildings and architects of California, Oregon and Washington. Also included are professionals in other fields who have made an impact on the built environment, such as landscape architects, interior designers, engineers, urban planners, developers, and building contractors. Building records are tied to those of their creators (when known) and include historical and geographical information and images. Bibliographical information, such as magazine and book citations and web sites, has also been linked for creators and their partnerships and structures.
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Prof. Dossick’s CM515 Spring 2024 Class. (2024). 2024 Innovation in the Construction Industry (Sturts Dossick, C., & Ray, L., Eds.). UW Libraries Pressbooks.
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Abstract
This book contains a series of case studies authored by graduate students in CM515 Virtual Construction Management Spring 2024. We explored how people, teams, and companies change practices with a variety of new technologies in the workplace. You will find cases of people who are innovators, teams who took on innovation, and specific design and construction projects that realized these innovation practice changes.
Keywords
Technology; Engineering; Agriculture; Industrial processes
The Inaugural CBE Climate Solutions Symposium took place on May 23, 2024. The event began with a reception and poster session, followed by an invited lecture “Every Project is a Climate Opportunity” with Don Davies, PE, SE and Joan Crooks. 36 research posters were submitted and accepted to the symposium. The posters covered a range of topics, from affordable housing in Indonesia (Bella Septianti, Architecture/Design Technology), to CLT and structural steel comparative lifecycle assessment (Mira Malden, Community, Environment, and Planning)….
Urban, M.C., Alberti, M., De Meester, L. et al. Interactions between climate change and urbanization will shape the future of biodiversity. Nat. Clim. Chang. (2024). https://doi.org/10.1038/s41558-024-01996-2
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Abstract
Climate change and urbanization are two of the most prominent global drivers of biodiversity and ecosystem change. Fully understanding, predicting and mitigating the biological impacts of climate change and urbanization are not possible in isolation, especially given their growing importance in shaping human society. Here we develop an integrated framework for understanding and predicting the joint effects of climate change and urbanization on ecology, evolution and their eco-evolutionary interactions. We review five examples of interactions and then present five hypotheses that offer opportunities for predicting biodiversity and its interaction with human social and cultural systems under future scenarios. We also discuss research opportunities and ways to design resilient landscapes that address both biological and societal concerns.
Tabatabaei Manesh, M., Nikkhah Dehnavi, A., & Rajaian, M. (2024). Using Machine Learning To Predict And Visualize Acoustic Quality In Educational Buildings. The 2024 International ConCave Ph.D. Symposium: Divergence in Architectural Research. Georgia Tech, Atlanta, April 4-5.
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Mohammad Tabatabaei Manesh is a computational designer and building science researcher with expertise in programming and building performance. He works on the application of machine learning and deep learning in building performance, developing web apps and tools for architects. Currently, Mohammad’s work focuses on the design, fabrication, and evaluation of acoustic metamaterials for the built environment.