123 Forum: Can Alkali-activated Materials Compete with Portland Cement?
Alkali-activated concrete (AAC) is a class of clinkerless binders made by activating aluminosilicates (e.g., fly ash or slag) with alkaline solutions. Alkali-activation is not a recent innovation—its first mention in scientific literature dates back to more than a hundred years ago. Over the past two decades however, researchers have focused intently on advancing AAC as an alternative to portland cement concrete. Despite widespread academic interest, the concrete industry has yet to adopt AAC into practice. Some experts question the sustainability of AAC; some challenge its long-term durability; others claim the materials and technology do not scale. This forum will discuss the practice-readiness of AAC, highlighting its perceived benefits and the obstacles that hinder its potential widespread acceptance.
Adjusting Workability for Successful 3-D Concrete Printing, Part 1 of 2
These sessions will be co-sponsored by RILEM Technical Committee 276-Digital fabrication with Cement-based Materials. Additionally, they will include presentations by U.S and international teams involved in 3DConcrete, an NSF AccelNet Program to enhance global network-to-network collaborations on concrete 3D printing. These sessions will highlight the importance of controlling fresh-state properties for the successful execution of 3D concrete printing (3DCP). 3DCP is a new method of casting that can introduce a number of advantages but there are also significant challenges, especially in controlling the viscoelastic properties of the concrete in the fresh state. Academic and industry researchers and practitioners interested in 3DCP should attend this session. Attendees will learn: i) the current state-of-the-art of 3DCP; ii) how rheology directly impacts printing performance; iii) strategies to effectively control workability for 3DCP; and iv) key challenges in bringing 3DCP to practice.
Adjusting Workability for Successful 3-D Concrete Printing, Part 2 of 2
These sessions will be co-sponsored by RILEM Technical Committee 276-Digital fabrication with Cement-based Materials. Additionally, they will include presentations by U.S and international teams involved in 3DConcrete, an NSF AccelNet Program to enhance global network-to-network collaborations on concrete 3D printing. These sessions will highlight the importance of controlling fresh-state properties for the successful execution of 3D concrete printing (3DCP). 3DCP is a new method of casting that can introduce a number of advantages but there are also significant challenges, especially in controlling the viscoelastic properties of the concrete in the fresh state. Academic and industry researchers and practitioners interested in 3DCP should attend this session. Attendees will learn: i) the current state-of-the-art of 3DCP; ii) how rheology directly impacts printing performance; iii) strategies to effectively control workability for 3DCP; and iv) key challenges in bringing 3DCP to practice.
Architects' Day Lunch and Learn
The Nubian Vault's mudbrick process has advantages for economic and educational growth in the building industry for local communities. As the revival of the Nubian Vault construct has taken hold in Sub-Saharan Africa, the rainy season continues to halt progress in Africa's more tropical regions. With assistance from Dwell Earth, a company founded by two brothers in Texas, and the measured use of concrete, the Nubian Vault's failures have the potential for success in the tropics. My presentation will look at the history of the Nubian Vault from ancient Egypt to Hassan Fathy's twentieth-century revival and the recent work of the French /Burkinabé NGO La Voûte Nubienne. Lastly, I will show the failed experiments and the subsequent potential for success.
Architects' Day Session: Achieving Excellence in Concrete Construction –
Following The REACH from Concept to Completion
This session will provide insight into the design and construction process of The REACH project (winner of the 2020 ACI Excellence Award) with a behind the scenes virtual “tour” of the project and insight into specifying concrete mix designs.
Architects' Day Session: Teamwork Makes the Dream Work
Learn how the architects, structural engineer, and formwork designers worked together to achieve the overall vision of The REACH.
Best Practices and Lessons Learned for Teaching Concrete Materials and Reinforced Concrete
This session features presentations associated with 11 collaborative papers written by groups of faculties who use some of the most innovative approaches to teach topics in concrete materials and reinforced concrete design at the undergraduate level. The session will include presentations related to general pedagogy, along with teaching hydration of cement, fresh and hardened properties of concrete, durability, additive manufacturing, nondestructive testing, detailing, the equivalent rectangular stress block, failure types of reinforced concrete beams, nonrectangular beams, and analysis and design for shear. The session will also include a presentation by the Walter P. Moore Award Winner.
- Effective Teaching Methods in Concrete Education by Matthew Swenty. Virginia Military Institute
- Pedagogical Approaches to Teaching Cement Hydration Processes to Undergraduate Students by Lisa Burris, Ohio State University
- Best Practices and Lessons Learned: Nondestructive Testing by Armen Amirkhanian, University of Alabama
- Innovative Pedagogical Approaches for Concrete Durability by Heather Kirkvold, James Madison University
- Pedagogical Approaches for Additive Manufacturing with Cementitious Materials by Jacob Henschen, University of Illinois Urbana-Champaign
- Teaching Concrete Through Context by Anahid Behrouzi, California Polytechnic State University
- Pedagogical Techniques Used to Teach Detailing of Reinforced Concrete Structures by Kacie D'Alessandro, Virginia Military Institute
- Understanding the Equivalent Rectangular Stress Block by Chris Carroll, Saint Louis University
- Teaching Flexural Strength (Failure Modes) in Reinforced Concrete by Royce Floyd, The University of Oklahoma
- Visualizing Non-rectangular Beams by Chris Carroll, Saint Louis University
- Approaches for Teaching Shear Analysis and Design of Reinforced Concrete by Royce Floyd, The University of Oklahoma
The Concrete Industry in the Era of Artificial Intelligence
The synopsis of this session is to educate researchers, practitioners, students, and officials on the merit of using AI in the concrete industry. Special attention will be paid to better the performance of concrete materials at ambient and elevated temperatures and showcase the substantial potential of using AI to improve design of concrete structures under traditional and fire conditions. Introduce AI and automation to the concrete industry.
Concrete Pavement Design and Construction Special Session Honoring Dr. Shiraz Tayabji
This session honors the many contributions made by Dr. Shiraz Tayabji to the American Concrete Institute and to the concrete pavement community as a whole. Dr. Tayabji is a long-time member of ACI, a Fellow, and a former chair of ACI 325, Concrete Pavements. To highlight the range of technical areas that Dr. Tayabji has contributed to throughout his distinguished career, this session includes presentations by prominent concrete pavement researchers and practitioners on important concrete materials, design, rehabilitation, and performance topics. The information presented in this session will be of interest to concrete materials engineers, pavement designers, and construction personnel.
- 40 Years of Concrete Pavement Innovations by Shiraz Tayabji, Advanced Concrete Pavement Consultancy LLC
- Theory Versus Reality in Concrete Airfield Pavement Engineering by Raymond Rollings, Rollings Consulting, LLC
- Continuously Reinforced Concrete Pavements by Dan Zollinger, Texas A&M Transportation Institute
- Concrete Strength Variability and Mix Design for Large Concrete Paving Projects by W. Charles Greer, Jr
- Durability of Concrete Pavement Materials by Peter Taylor, National Concrete Pavement Technology Center
- Precast Concrete Pavements by Mark B. Snyder, Pavement Engineering and Research Consultants, LLC
- Concrete Overlays by Julie Vandenbossche, University of Pittsburgh
- Recent Innovations for CRCP by Jeffery Roesler, University of Illinois at Urbana-Champaign
Constructability and Shotcrete Construction in the Windy City
Constructability analysis of the structural systems is a key step in optimizing time, quality, and economic considerations of a project. Shotcrete construction practices and techniques are used to an advantage on multi story projects. This session looks to case studies, best practices, and material sciences for strategies to best achieve a building structure that meets the demanding requirements of the industry.
Exploiting SSI Effects in Structural Design of Bridges
Soil structure interaction (SSI) effects are studied through instrumented bridges in the field and extensive dynamic analyses. Studies show that foundation compliance owing to SSI attenuates seismic demands in monolithic bridge piers but may accentuate seating demands for bearing supports in bridges that are not continuous with the piers. This session aims to assess the design implications of SSI in controlling the pier/bearing demands as a retrofit measure in existing bridges, as well as to establish a framework for its explicit consideration in new seismic design of bridges, particularly in seismic events of large intensity.
Fusion of Visual and Nondestructive Techniques for Bridge Evaluation
The session will discuss the use of multiple nondestructive testing (NDT) methods for assessing the conditions of aging concrete bridges and how data fusion can be used to combine and “image” both visible surface conditions and unseen internal conditions. Thus it is anticipated that speakers will cover the use of a wide range of NDT methods for bridge decks, superstructure and substructure condition assessment and their fusion with one or more additional methods including: computer-based photographic mapping of cracking/spalling damage; infrared thermography; ground penetrating radar; acoustic/impact echo/surface waves scanning of decks; and, corrosion activity mapping with half-cell potential, resistivity and polarization methods.
How to Get Modern Concrete Pumped to the Right Floor
High rise construction, specifically in Chicago, is continuing to push the limits of what is possible with concrete. Buildings are going up higher and developers are requesting more livable square footage, requiring concrete with very strict requirements and specifications. This results in a chain of preparation once a building is announced from the mix design development and raw material sourcing, to the testing of the mix design meeting specification, to the contractor who will do the placement and construction. Individuals in each stage of the process must work together to ensure a successful project. Collaboration and information exchange between designers, architects, contractors, producers, and testing labs needs to be streamlined and improved to ensure that the structural properties of the material can be matched with constructability. Testing labs should be more involved with the design and certification of mix designs to ensure that the specification is being adhered to, while contractors need to take the concrete and place it in the building. As such, it needs to be pumpable and workable once it comes out of the pump 60+ stories in the air, which adds an additional constraint placed upon all who are involved. Designers require more specific properties of materials, which results in substantial challenges in finding the appropriate materials and mix designs.
Is SCC Consolidation-Free?
Mixtures designated as self-consolidating concrete (SCC) may need a certain amount of consolidation to eliminate surface blemishes, to flow through congested areas, and to meet slump flow loss during construction. Care must be exercised in consolidating highly flowable mixtures such as semi SCC and SCC because they can lose stability. This session will address the consolidation needs of semi SCC and SCC and the effects of type and duration of vibration on the stability of these mixtures. There will be case studies and lessons learned. Researchers, engineers, contractors, and practitioners will benefit from the experience of the presenters.
The Future of Coal Combustion Products in Concrete, Part 1 of 2
Fly ash has been the most widely used SCM in concrete for decades. For this reason, significant changes in its production and quality during the last 10 years, have driven a growing interest in harvesting fly ash from impoundments or landfills for use in concrete. Processed coal bottom ash and other CCPs that are currently not used in concrete have also been identified as an emerging supplementary cementitious materials that can help meet the demand for materials that can impart fly ash-like benefits to concrete. This session will provide the opportunity to learn about the characteristics and performance of new and emerging coal combustion products for use in concrete. Students, academics, concrete producers, contractors, specifiers and material suppliers will benefit from the information presented in this session.
The Future of Coal Combustion Products in Concrete, Part 2 of 2
Fly ash has been the most widely used SCM in concrete for decades. For this reason, significant changes in its production and quality during the last 10 years, have driven a growing interest in harvesting fly ash from impoundments or landfills for use in concrete. Processed coal bottom ash and other CCPs that are currently not used in concrete have also been identified as an emerging supplementary cementitious materials that can help meet the demand for materials that can impart fly ash-like benefits to concrete. This session will provide the opportunity to learn about the characteristics and performance of new and emerging coal combustion products for use in concrete. Students, academics, concrete producers, contractors, specifiers and material suppliers will benefit from the information presented in this session.
Integration of Innovative Techniques and Approaches for Optimum Concrete Structure Rehabilitation
This session intends to present case studies or projects where innovative techniques were used to assess the condition of concrete structures and plan rehabilitation strategies. The techniques include nondestructive testing, corrosion measurements, modeling, and monitoring. The session is meant for engineers and practitioners.
Legal Issues in Concrete Construction - Lessons Learned
This session will bring together four individuals with extensive experience in litigation related to concrete construction. The speakers will share their experiences as lawyers, expert witnesses, and engineers through case studies and will share their experience-based recommendations.
Microbially Induced Corrosion of Concrete
Corrosion of concrete in sewer infrastructures is a worldwide concern. Although the mechanism of this corrosion was discovered in the middle of last century, it was not a universal concern until the late 1990s. Since then, research has confirmed that the cause of this corrosion is a biogenic acid attack. Solutions for mitigation and testing processes for assurance have been developed. This session is for anyone interested in knowing exactly what causes sewer corrosion and what methods of mitigation are available.
Performance of Slag Cement with Portland-limestone Cement in Concrete
Early-age performance of slag cement with Type IL cement has been found to be equal to or better than with Portland cement from the same source. The alumina in the slag cement can react with more of the finely divided limestone to form additional carboaluminate hydrates that then results in reduced porosity and increased early-age strength. There is also reduced permeability, as indicated by ASTM C1202 test results.
While some early published papers indicated a potential concern for an increased risk of low-temperature thaumasite sulfate attack, our extensive long-term tests on concretes have shown that Type IL cement- slag cement combinations are as resistant to sulfate attack as Type I cement-slag cement combinations and more resistant than equivalent w/cm concretes made with Type V cements to both the ettringite and thaumasite forms of degradation.
This course will include discussion on these two topics and will also look at some recent projects with these materials. Speakers will walk through different reaction rates such as resistivity and diffusion with portland limestone cements, strength results and modeling.
Research in Progress
The synopsis of this session is to educate researchers, practitioners, students, and officials on the merit of This session will feature presentations of original, unpublished results from ongoing research projects and leading-edge concrete technology and research throughout the world.
Rethinking Reinforcement for 3-D Printed Cementitious Composites
The fabrication of novel reinforced concrete structures using digital technologies requires the definition of suitable strategies for reinforcement implementation. Reinforcement integration must be compatible with either the shape or the specific printing technique adopted for each structural element production. This session aims to provide the latest updates on opportunities and techniques using “reinforced concrete” for engineers, architects, and researchers actively involved in or simply interested in three-dimensional (3-D) printing with cementitious composites. These techniques have been developed to further expand the outreach of digitally fabricated concrete materials and structures.
Smart Concrete, New Functionalities, and Nanotechnology
Nanotechnology has the potential to revolutionize the properties of concrete. Conversation in this session is designed to explore the impact of nanomodification on creating concretes with new functionalities, such as sensing and damage detection, self healing, energy harvesting, deicing applications, and so on. This session provides a unique opportunity for engineers, scientists, and industry leaders to learn and experience new concepts and novel research areas on the use of nanotechnology in cementitious materials and concrete.
UHPC – Innovations in Practical Applications
Ultra-high-performance concrete (UHPC) is seen as one of the most influential material innovations in the construction industry in the twenty-first century. Many research groups in academia or industry worldwide have developed UHPC mixtures, investigated their material properties and their structural behavior and thus have contributed to the increased interest in this type of material. While design guidelines are being drafted or have already been published the application of UHPC has been surpassed the stage of pilot projects in some areas. It seems that UHPC finds more and more ways into the construction industry beyond the “killer application” which was sought in the early days. This session will invite national and international research groups, material suppliers and contractors to share their knowledge in innovations in practical applications.
Unlocking Workability Issues of UHPC
Ultra-high-performance concrete (UHPC) is attracting increasing interests worldwide due to its superior mechanical properties and excellent durability. However, the difficulties in handling of UHPC has been increasingly recognized as a major problem during construction because of a significant workability reduction due to very low water-binder ratio (w/b) and very high dosages of fine powders (for example, silica fume) and admixtures (for example, water-reducing admixtures) used. It is well understood that mixing methods and procedures have more substantial effects on workability of UHPC than on those of conventional concrete. Ultra high performance could not be achieved if required workability of UHPC is not met. The main objective of this technical session is to uphold a platform to discuss the issues, challenges, and recent advances in characterizing, controlling, and improving workability of UHPC. It is also to promote broader dialogue and greater interactions between UHPC researchers and users.
Using ACI 318 PLUS as a Teaching Tool
This session will provide background on the creation of the new ACI 318 PLUS subscription along with guidance on how educators can navigate some of its key features and leverage it as a tool to improve students’ understanding of reinforced concrete design. Discussion will be included to allow for brainstorming ideas on how this platform could better enhance teaching ACI CODE-318-19. Speakers include Michael L. Tholen, Ph.D., P.E and Trey Hamilton Ph.D., professor emeritus at the University of Florida.
Adapting and Reuse of Concrete Structures
This session focuses on the preservation and adaptive reuse as alternatives to the replacement of built structures in the pursuit of sustainable built environment
Advancing Concrete Durability, A Special Session Honoring Michael Thomas
This session will honor Michael Thomas, PhD, PEng, FACI, FICT, for his extensive contributions to advancing cement and concrete research, and his service to the concrete industry. Various industry leaders will discuss the impacts of the research conducted by Dr. Thomas and his students in the areas of supplementary cementitious materials (SCMs), alkali-silica reaction (ASR) mechanisms, mitigation, and testing; sulfate resistance; chloride-induced corrosion; and other areas of concrete durability.
- Life-365: Stories and Choices About Development by Evan Bentz, University of Toronto
- Relating ASR Lab Tests to Outdoor Exposure Site Performance - More Research is Needed by Benoit Fournier, Laval University
- Understanding How Supplementary Cementitious Materials Suppress ASR by Karen Scrivener, Ecole Polytechnique Fdrale De Lausanne
- Contributions of M. D. A. Thomas to PCA Research by Michelle Wilson, Portland Cement Association
- Durability Performance of Concrete Exposed to Harsh Marine Environments by Ted Moffatt, WSP
- A Practical Guide to Life, Liberty, and the Pursuit of Concrete Durability (Sulfate Attack and DEF in Particular) by R Doug Hooton, University of Toronto
- Tales From the Road by Kevin Folliard, University of Texas At Austin
- Comments From Michael Thomas by Michael Thomas, University of New Brunswick
Applications of Alternative Cements
This session will provide state of the art discussion on the use of alternatives to Portland cement, with a focus on processes for upscaling the use of alternative cements (ACMs) and understanding beneficial applications in which ACMs can be used in lieu of Portland cement to create more durable, sustainable, and resilient concrete. The session targets both researchers working to advance understanding of ACMs and industry users (suppliers, producers, owners) interested in applying ACM technology to their work.
Architects' Day Lunch
Buildings alone account for 40% of the global greenhouse gas emissions. Two thirds of that total impact is from operational emissions while the remainder is from embodied emissions. Embodied emissions include all the emissions required to produce everything that goes into our buildings – the structure, enclosure and all the materials inside. Between now and 2050, half of the new construction emissions between now and then will be from embodied carbon. Therefore, the industry has begun to take action and groups like AIA 2030, Architecture 2030, SE2050, and USGBC have shifted their focus to include embodied carbon. In order to address this issue, we need to take steps to quantify and then reduce our impact. We can do this using a process called Whole Building Lifecycle Assessment (WBLCA). More and more project teams are using WBLCA as a design tool and are discussing decarbonizations strategies. As such, design professionals are actively and looking for low carbon material alternatives. Since cement is such a ubiquitous and carbon-intensive material, it is definitely at the center of these discussions. It’s important that the concrete industry be aware of what is being discussed in the market and how this will affect our industry in the future as this trend grows. This presentation will also look at examples of how this translates to the design documents, the specifications and ultimately the concrete mix designs.
Architects' Day Session
Our over-arching theme is “The Evolution of Concrete” where we will discuss sustainability, labor trends, and admixture/reinforcement, design and how they overlap and impact each other.
Calcined Natural Pozzolans, Including Calcined Clays
This session will address both fundamentals of pozzolan activation through calcination, considering relatively pure and impure natural sources, and practical use of these materials in concrete construction. The intended audience includes engineers, contractors, researchers, and students interested in alternative sources of pozzolans. It will cover the fundamentals of pozzolan calcination, including effects of composition and processing, on structure and performance. The session will also address practical use of calcined pozzolans at an industrial scale.
- Tailoring Calcined Impure Clays for Improved Performance by Katelyn O'Quinn, University of Texas
- Activation of Na- and Ca- Bentonites: Comparison of Thermal and Mechanical Treatments by Alastair Marsh, University of Leeds
- Impact of Calcined Clay Particle Size on Mortar Performance by Anna Landreville, Imerys Performance Minerals
- Understanding the Role of Calcined Clay on Pore Structure and Transport Properties of Cement Composites by Yuvaraj Dhandapani, University of Leeds
- Monte-Carlo Based Thermodynamic Analysis on the Performance of Calcined Clays in Cementitious Systems by Keshav Bharadwaj Ravi, Oregon State University
- Pozzolanic Reactivity and Performance of Calcined Byproduct Clays of Various Kaolinite Contents in Concrete Mixtures by Khashayar Jafari, Pennsylvania State University
- Metakaolin in Concrete: The Role of Alumina by Michael Thomas, University of New Brunswick
- Industrial Experience with Production and Use of Calcined Clay-Limestone Cement by Jesper Damtoft, Cementir Holding
- Implementation of LC3 in the Field by Karen Scrivener, Ecole Polytechnique Fdrale De Lausanne
- Using Metakaolin for Enhancing Durability and Mitigating Alkali-Silica Reaction (ASR) in Concrete by Frank Ong, Master Builders Solutions US
- Predicting the Rheology of Limestone Calcined Clay Cement (LC3) by Ogulcan Canbek, Georgia Institute of Technology
- Physical Properties and Durability Performance of a Canadian Calcined Clay by R Doug Hooton, University of Toronto
Carbon Neutral - How Do We Get There?
Activities to achieve carbon neutrality in concrete construction are currently pervasive throughout the concrete industry. Industry associations and companies, along with various organizations outside our industry, are focusing their efforts and dedicating resources to achieve carbon neutrality in construction. A wide array of technologies are being deployed by the cement and concrete industry while other technologies are under development. This session will provide an overview of the carbon neutrality issue and will highlight strategies and technologies being implemented or being developed to achieve carbon neutrality.
Computer Simulations and Analytical Methods for Concrete 3-D Printing
Concrete 3-D printing has quickly become a hotbed of research and case studies for the field; yet the related computational models and analytical methods for simulating such techniques are still in their infancy. This session is targeted toward engineering mechanists, computational scientists, and those interested in the simulation of early age concrete behavior. Presentations will focus on state of the art 3-D printing modeling techniques, including analytical methods, as well discrete element, lattice discrete element, and finite element models.
Concrete Through the Ages
This session is intended to introduce individuals to the historical aspects of concrete and concrete construction practices. Attendees will gain a greater understanding and appreciation of the development of the concrete industry.
Concrete With Recycled Materials
Concrete is the world’s most widely used construction material. Yet, the production of portland cement, an essential constituent of concrete, leads to greenhouse gas emissions into the atmosphere. The production of 1 ton of portland cement clinker releases approximately one ton of CO2 and other greenhouse gases. Environmental considerations have been a major thrust for the sustainable development of the cement and concrete industries. A sustainable concrete structure is designed and built to have a positive environmental footprint during its entire life cycle. Concrete is increasingly being considered as a sustainable material owing to its low inherent energy requirements and little associated waste. Not only is it made from some of the most plentiful resources on Earth, it can also be made with numerous recycled materials and by-products and is itself entirely recyclable. Emerging breakthroughs in concrete technology have allowed producing ultra-high-performance concrete requiring less raw materials, along with structures that are much more durable to reduce maintenance, repair, and reconstruction.
Design and Construction for LNG and other RLG Containment Structures
ACI 376-11/376M-11 Code Requirements for Design and Construction of Concrete Structures for the Containment of Refrigerated Liquefied Gases and Commentary was adopted by ACI in November 2011 and published in August 2013. The committee had been formed in 2003 at the request of the national Fire Prevention Association (NFPA) Technical Committee 59A on liquefied natural gas (LNG) for the purpose developing a code document that could referenced by NFPA 59A for design and construction of concrete containment structures. The scope of the Code includes not just LNG, but all refrigerated liquefied gases (RLG) where concrete is used for storage and containment. Upon completion of the first edition the committee began the work of addressing the future action items from the first edition, and other changes brought before the committee.
Durability, Service Life, and Long-Term Integrity of Concrete Materials, Bridges, and Structures
Durability is one of the most important requirements for sustainable infrastructure. Federal, state, and local agencies expend significant effort to maintain the quality and condition of aging civil structures, especially those in aggressive service environments. Among many factors, durability influences the service life and integrity of concrete materials and structures. Extensive research has been conducted to understand the deterioration mechanisms of concrete in an effort to extend the longevity of concrete members. In this session, presentations of both experimental and analytical investigations are of interest, which may include the durability of concrete structures reinforced with steel or fiber-reinforced polymer bars, modeling of service life for concrete under aggressive environments, and the structural integrity and resilience of rehabilitated members. The session emphasizes recent research findings and provides an opportunity to discuss present challenges and technical issues. Critical information is given to those who lead tomorrow’s structural design and construction with an emphasis on durability, service life, and integrity, including practicing engineers, government officials, and academics.
Graphene-Based Admixtures in Concrete
Graphene and its derivatives present a relatively new family of nanomaterials featuring unique quasi-2D layered structure. The thickness of single-layered graphene nanosheets is approximately 1 nm, while the median size of the lateral dimension is about 4 µm depending on the specific preparation method. Similar to carbon nanotubes and carbon nanofibers, graphene can be employed to endow cementitious materials with smart functionalities (e.g., by monitoring their stress-strain behavior). Recent laboratory studies have increasingly demonstrated that the oxygen-containing functional groups on the surfaces of graphene oxide (GO) and reduced GO make them a new type of multifunctional admixtures for cementitious materials. This session will bring to light to new frontiers and recent research findings and provide an opportunity to discuss the present challenges and technical issues. The session aims to engage a diverse group of distinguished speakers and serve to inspire researchers and practitioners who are interested in the use of graphene-based admixtures in paste, grout, mortar, and concrete.
Live Load Distribution on Concrete Bridges: Design, Evaluation, Construction, Innovation
The session will focus on live load distribution issues for concrete bridge decks and supporting girders. In addition to discussing the AASHTO methodology, other available codes/specification provisions will be reviewed. Potential topics related to live load distribution include, but are not limited to, simplification of the AASHTO methodology, traffic non-parallel to girders, construction stage issues, partial composite deck-girder systems, long-span girders, slab-span structures, and bridges with missing as-built plans.
- Load Rating of Damaged Double-Tee Girder Bridges by Mostafa Tazarv, South Dakota State University
- Load Testing of a Deteriorated Prestressed Concrete Girder Bridge without Plans by Sebastian Castellanos-Toro, Universidad Del Valle Cali
- Evaluation of Existing Prestressed Concrete Bridges and Live Load Distribution by He Zhang, Rutgers University
- Live Load Distribution Factors in an I Girder Concrete Bridge with Excessive Vibration and Partial Deck Girder Composite Action by Ikram Efaz, University of Texas Arlington
- Live Load Distribution of Slab-on-Girder Bridges Using Vision-based Measurements by Monique Head, University of Delaware
- Effects of Barriers on Load Distribution in a Concrete Slab Span Bridge by Kendall Hill, University of Minnesota Duluth
- Exploring Effects of Freight and Emergency Vehicles on Distribution Factors of Concrete T Beam Bridges Using Refined Analysis and Machine Learning by Abdou Ndong, University of Virginia
- Evaluation of In Service Reinforced Concrete Box Culverts through Diagnostic Load Testing and Refined Analysis by Amir Gheitasi, WSP USA
- Live Load on Concrete Bridge Decks by Sylwia Stawska, Auburn University
- Using Finite Element Analysis for Assessing the Live Load Distribution for Solid Slab Bridge Evaluation and Design by Bruno Massicotte, Polytechnique Montreal
- Experimental Investigation and Refined Load Rating of a Concrete Pan Girder Bridge by Nuzhat Kabir, Texas A&M University
Major Opportunities for Concrete Structures to Support Large Wind Turbines
To introduce the ACI community to concepts and opportunities to provide support structures (towers and foundations) for wind turbines. This would include tall towers for onshore wind, as well as gravity-based and floating concrete foundations for offshore wind turbines. The use of concrete support structures provides many advantages over steel solutions. For onshore wind support structures, these includes addressing transportation and erection challenges and lower costs. In addition to these, for offshore wind turbines the advantages include much longer design lives, local fabrication capacity, and overcoming the impact on sensitive marine habitats such as the North Atlantic Right Whale.
Open Topic Session
The Open Topic Session is a forum for presenting recent technical information that could not be scheduled into other convention sessions.
Paper Awards-Published in 2020
Awarded authors of papers published in 2020 will present winning papers. Awarded categories include: the ACI Concrete International Award, the ACI Symposium Volumes Award, the Mete A. Sozen Award for Excellence in Structural Research, the Wason Medal for Materials Research, and the Wason Medal for Most Meritorious Paper.
Recent Advances in the Behavior of Reinforced Concrete Columns: A Session Honoring the Memory of Dr. Asad Esmaeily
Dr. Asad Esmaeily was a Professor of Structural Engineering at Kansas State University between 2002 and 2018. He was an active member of ASCE-ACI joint committee 441 on Reinforced Concrete Columns for almost 18 years. He was a major contributor to the recently published document ACI 441.1R-18. His area of research was in reinforced concrete columns and health monitoring of structures. He passed away in June 2018 at an age of 59 after a short battle with cancer. His colleagues, students and fellow committee members want to pay a small tribute to him by organizing this session in his memory. ASCE-ACI joint committee 441 is sponsoring the session. The session addresses recent advances in the behavior and modeling of reinforced concrete columns subjected to different loading conditions with the presence of innovative materials. The audience of this session are anticipated to be practitioners and researchers in the area of behavior, analysis, and design of reinforced concrete columns.
Research in Progress
This session will feature presentations of original, unpublished results from ongoing research projects and leading-edge concrete technology and research throughout the world.
- Evaluation of Stress in Prestressed Concrete Structures Based on Acoustoelastic Effect by Bibo Zhong, University of Nebraska Lincoln
- Load Distribution in a Concrete Slab-Span Bridge by Kendall Hill, University of Minnesota Duluth
- Torsional Testing of Cement-Based Materials for Estimating Shear Strength by Subodh Mhamankar, Kansas State University
- Ultrafast Stiffening of Concentrated Thermoresponsive Suspensions for Additive Manufacturing by Sharu Kandy, University of California, Los Angeles
- Investigation on Protecting Mechanism of Soy Methyl Ester-Polystyrene (SME-PS) as a Concrete Surface Protectant by Mohammad Houshmand, Drexel University
- Revised Creep and Shrinkage Design Model using Solidification Theory by Timothy Clement, University of Minnesota Duluth
- Mitigation of Alkali-Silica Reaction in Concrete Using Novel pH Reducing Admixtures by Gopakumar Kaladharan, Pennsylvania State University
- Toward a Clinker-Free Binder for Concrete by Melissa McAlexander, Oregon State University
- Effects of Thermal Cycling Rate and Pore Confinement on Thermal Behavior of Phase Change Materials in Lightweight Aggregates for Deicing and Low-Temperature Applications by Robin Deb, Drexel University
- Does ITZ Influence Moisture Transport in Concrete? by Laura Dalton, North Carolina State University
- Mitigating Steel Corrosion in Reinforced Concrete Structures Using Hydrophobic Sealer by Goran Adil, University of Missouri-Kansas City
Seismic Repair/Retrofit/Strengthening of Bridges at the Element or System Level
Major seismic events around the world along with the aging and deterioration of infrastructures keep increasing the need for repair/strengthening and rehabilitation of existing bridges. Seismic repairing and strengthening are an area that has seen major developments due to the availability of robust numerical simulation frameworks, large experimental facilities, structural health monitoring techniques, development of advanced materials and construction techniques, and sophisticated performance-based seismic design and assessment methodologies. Despite the progress, there are many challenges yet to be addressed. With the increase in transportation demand and more stringent seismic performance requirements, bridge retrofit, and repair is an important task for engineers and researchers. Bridge retrofits usually involve functional upgrades (such as deck widening) and seismic upgrades (such as strengthening seismic load path). The effects of the two upgrades are usually coupled and need to be analyzed. Therefore, more sophisticated analysis and customized solution is needed. While providing structural upgrade solutions to seismic issues, engineers also need to reduce the interruption to the traffic as much as possible. Development and implementation of innovative retrofit and repair methods are expected to upgrade deficient bridges to current standards and minimize traffic interruption. The main objective of this session is to present results from recent research studies (experimental/numerical/analytical) and practical examples of existing bridge retrofit and repair. This session will provide a forum for practicing engineers and researchers to share and discuss the various issues related to design and construction issues of seismic repair/retrofit/strengthening of bridges at the element and system level.
- Seismic Retrofit and Quick Repair Technique for Bridge Columns Through Transverse Prestressing by Murat Saatcioglu, University of Ottawa
- Shape Memory Alloy Based Dampers used for Seismic Retrofit of Continuous Bridges with Unequal Height Piers by Nailiang Xiang, Nagoya Institute of Technology
- Rapid Repair of Reinforced Concrete Columns Using a Mechanically Fastened Steel Jacket by Taylor Brodbeck, North Carolina State University
- Proposed Shear Design Equation and Reliability Analysis for Shear-Critical RC Beams Strengthened with Inorganic Composites by Tadesse Wakjira, The University of British Columbia
- Rapid Repair of Hollow-Core FRP-Concrete-Steel Columns by Mohamed ElGawady, Missouri S&T
- Multi-Column Bridge Bent Considering Different Jacketing Options by Abu Chowdhury, University of British Columbia
- Precast Bridge Columns with Replaceable Components for Quick Repair by Mostafa Tazarv, South Dakota State University
- Seismic Performance of Retrofitted and Repaired Bridge Column Under Major and Several Aftershocks by Saif Aldabagh, University of British Columbia
- Full-Scale Evaluation of a Repair Measure of Earthquake Damaged Bridge Column by A K M Golam Murtuz, Portland State University
- Behavior of UHPFRC Strengthened Bridge Piers Under Lateral Impact Loads by Gholamreza Gholipour, Lakehead University
- Performance-based Seismic Assessment of Highway Bridges with Superelastic SMA Reinforced Piers and Restraining Devices by Shuai Li, The University of British Columbia
Shrinkage-Compensating Concrete Design and Research in Memory of Edward K. Rice
The objective of this session is to introduce the latest design and research of using shrinkage compensating concrete for various structural concrete, including bridge decks, and in structural repair materials to help avoid drying shrinkage cracking. Different types of shrinkage compensating concrete will be discussed and how it is produced in design mixes and how it effects early strength properties in comparison to normal Portland cement design mixes.
UHPC – Hot Topics
In the last decade ultra-high-performance concrete (UHPC) has significantly attracted the interest of researchers and practitioners due to its material performance and its potential for innovative practical applications. It has become one of the most influential materials in the construction industry in the twenty-first century. After years of innovations in material, structural and architectural design what are the current UHPC hot topics? This session will invite national and international research groups, material suppliers and contractors to share their knowledge of hot topics of UHPC.
- Structural Response of UHPC Columns by Mahmoud Aboukifa, University of Nevada
- Performance Evaluation of Ultra‐High‐Performance Fiber‐Reinforced Concrete Columns (Development of P‐M Interaction Diagrams) by Marwa Mahmoud Ibrahim, University of Calgary
- Design UHPC Structure with High Deformation Capacityt by Yi Shao, Stanford University
- Identification of the Tensile Constitutive Relationship for UHPC: Indirect Tension Tests vs. Back Analysis of Flexural Tests by Dr. Liberato Ferrara, Polytechnic University of Milan
- Strain Capacity of Strain‐Hardening UHP‐FRC Part I: Steel Fibers by Dr. Antoine E Naaman, University of Michigan
- Strain Capacity of Strain‐Hardening UHP‐FRC Part II: Synthetic Fibers by Surendra Shah, The University of Texas at Arlington
- Implementation of UHPC for Long-Span Precast Pretensioned Elements: Materials by John S Lawler, Wiss, Janney, Elstner Associates, Inc.
- Development and Testing of High/Ultra High Performance Concrete for Durable Bridge Components and Connections by Kay Wille, University of Connecticut
- Non‐Proprietary Ultra‐High Performance Concrete for Precast Bridge Decks Field Joints by Dr. Mohamed Moustafa, University of Nevada, Reno
- Performance Density Diagram Developed with Machine Learning Models to Optimize Mixture Design of Sustainable UHPC by Cesario Tavares, Texas A&M University
- Experimental Behavior and Numerical Modeling of Reinforcement by Dr. Matthew J Bandelt, New Jersey Institute of Technology
- New Approaches to Architectural UHPC by Larry Rowland, Ceentek North America
- UHPC Overlay Installation Methods – Contractor Perspective by Peter Seibert, UHPC Solutions
- Effect of Thixotropic UHPC on Interfacial Properties as an Overlay by Jiang Du, Stevens Institute of Technology
- Seismic Performance of Reinforced Concrete Columns Strengthened with Ultra-High-Performance Fiber Reinforced Concrete and Shape Memory Alloy by Adel Al Ekkawi, University of Calgary
- Field Implementation of UHPC Beam End Repair on Steel Girder Bridges in Connecticut by Alexandra Hain, University of Connecticut
- Sprayed UHPC for Structural Reinforcement or Protection by Sebastien Bouteille, CETU