Sessions & Events


All sessions and events take place in Eastern Daylight Time (EDT).
W = Westin Boston Seaport District; C = Boston Convention and Exhibition Center

On-demand sessions will be available for viewing in the convention platform under "On-Demand Content" within 24-48 hours of the session premiere. Please note, on-demand sessions are not available for CEU credit. *Denotes on-demand content.

UHPC – New Developments in Sustainability

Sunday, October 29, 2023  3:30 PM - 5:30 PM, W-Marina Ballroom II

Ultra-high-performance concrete (UHPC) continues to attract more researchers, engineers, architects, students and experts across disciplines due to its fascinating material properties. Although it is known that UHPC has excellent mechanical and durability properties, its effect on the sustainability of structures using UHPC technology in part or fully is often not quantifiable, yet. The development of mixture designs with lower carbon footprint is an exciting direction to further affect the sustainability impact of the material on our structures. In addition, the UHPC material properties offers to construct and maintain in a much more environmentally friendly way. The quantification is challenging and might remain challenging in the upcoming years. Research emphasizing life cycle analysis is under way to close part of the knowledge gap.

This session will invite national and international research groups, material suppliers and contractors to share new developments in sustainability of UHPC technology.

Learning Objectives:
1) Discuss about the sustainability potential of UHPC technology;
2) Recognize knowledge gaps;
3) Review new sustainable developments in use and application of UHPC;
4) Analyze the impact of UHPC on the sustainability of our future infrastructure.

This session has been approved by AIA and ICC for 2 PDHs (0.2 CEUs). Please note: You must attend the live session for the entire duration to receive credit. On-demand sessions do not qualify for PDH/CEU credit.

Is UHPC a Sustainable Construction Material? Holistic Assessment Through a LCA/LCC Perspective of the Material and Structural Durability

Presented By: Liberato Ferrara
Affiliation: Polytechnic University of Milan
Description: The ever-changing needs of the end user in the construction industry, together with the increasing awareness about the great influence of the sector on the worldwide sustainability, require some tools to be employed by the stakeholders to drive the market towards conscious and appropriate choices. An example in this regard are advanced cement-based materials that, either by partially replacing cement with supplementary cementitious materials and virgin aggregates with recycled ones or by increasing durability, are generating interest in the market thanks to their potentially better environmental performance. Therefore, besides the sustainability analyses such as the Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) ones, some recent literature already tackled the problem proposing a more immediate evaluation approach represented by a series of indexes which are focused on the ecological and structural (generally, the compressive strength) performance of the material. To this end, from a comprehensive perspective, in this work two indexes are proposed able to include a wider range of environmental performances besides the costs and the durability characteristics. One is aimed to determine the suitability of using certain cementitious materials, encompassing the aforesaid parameters for the cubic meter scale. A second one is aimed to define the best mix design to be used to build certain structures (or components). For such purpose, the case of precast panels made with Ultra High-Performance Concrete (UHPC) is here addressed, to assess the consistency of such indexes, upgrading from the material scale to the product scale. For this purpose, in this paper, Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) methodologies are integrated into a Durability Assessment-Based Design (DAD) workflow which combines structural design algorithms for UHPC with the assessment of the durability performance, to predict the evolution of the structural performance all along the

Performance Prediction of Low CO2 and Low Cost UHPC Using Machine Learning

Presented By: Deepika Sundar
Affiliation: Pennsylvania State University
Description: A major challenge in the design of non-proprietary UHPC mixtures is reducing the cost and carbon footprint. Extensive experimentation is often required to determine optimal mixture proportions that both meet the design performance requirements of strength and workability while also meet CO2 and cost targets. This talk focuses on prediction of flow and strength properties of non-proprietary UHPC based on mixtures proportions inputted by a user. A database of over 500 non-proprietary UHPC mixture designs was assembled based on the literature and the authors’ in-house testing in order to understand the impact of the constituents and mix design parameters on the static spread and 28-day compressive strength. The dataset was then used to develop reliable and robust machine learning models for property prediction, by integrating prior physical knowledge such as cement type, sand type, and maximum size of aggregates. The resulting optimum model enables a UHPC designer to utilize locally available materials and predict the performance, cost, and CO2 footprint of various mix design alternatives with the goal of minimizing the cost and CO2. The utility of the model will be demonstrated using several examples utilizing locally available mixture constituents, including limestone filler, other SCMs, and natural sand.

Development of Sustainable Eco-UHPC with Recycled Mineral Fillers from Locally Available Industrial By-Products in Quebec

Presented By: Luca Sorelli
Affiliation: Université Laval
Description: The use of Recycled Mineral Fillers (RMF) in the development of ecological Ultra-High-Performance Concrete (UHPC) is a promising approach for reducing the environmental impact of concrete structures. This study conducted at Université Laval explores this approach by recycling LCLL ash from aluminum smelters and granite dust from local quarries as sources of RMF. The mix design was first optimized using an extended compaction interaction method to maximize the packing density of powders. The microstructure of the cement paste was analyzed using SEM-BSI and micro indentation, demonstrating that the mineral fillers effectively fill the micrometer voids and are well bonded with the hydrated products. Calorimeter tests and TGA tests were conducted to assess the effect of these mineral fillers on the cement hydration or reactivity. Finally, pull-out, compression, and bending tests were performed on the UHPC with granite dust as mineral fillers, indicating that it is a promising method for creating sustainable eco-UHPC with low cement content by recycling fine powders.

The Next Generation of Ultra-High-Performance Concrete (UHPC) Bridges in Canada: Sustainable Material for Bridge Infrastructure

Presented By: Philip Loh
Affiliation: Facca Incorporated
Description: Sustainable infrastructure considers the following three factors: economic, social and environmental. This presentation shows an investigation of using Ultra-High-Performance Concrete (UHPC) as a sustainable environmental material for bridge infrastructure and that it is possible to reduce environment impact by increasing the strength of concrete. Examples of the environmental impact calculations of UHPC structures compared to that of concrete box girder design and also of steel box girder design are presented. The comparison studies show that many structures constructed from UHPC are in general more environmentally sustainable than using conventional structural materials with respect to the reduction of CO2 emissions, embodied energy (EE) and global warming potential (GWP).

Shear Response of UHPFRC Prestressed Beams Reinforced with Varying Amounts of Fibers

Presented By: Sri Sritharan
Affiliation: Iowa State University, Facca Incorporated
Description: Compared to conventional concrete, Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) has exceptional mechanical and durability properties. However, due to its high cost and limited understanding of its structural behavior, its widespread application in construction remains limited. To address this, a non-proprietary UHPFRC concrete has been developed using locally available materials to reduce initial costs. Additionally, the shear behavior of post-tensioned UHPFRC concrete beams has been experimentally investigated. The study considers three parameters: the level of prestressing (0%, 35%, and 70% of ultimate tensile strength of strand), the volume fraction of fibers (1.0% and 2.0%), and different types of steel fibers (straight and hybrid). The beams were tested, and their principal tension and compression strain along and across the cracks were measured throughout the loading process. The results were compared with tension localization strains from the direct tension test. The failure mode was found to be due to post-cracking tensile resistance rather than concrete crushing. As the level of prestressing increased from 0% to 70% of the ultimate tensile strength of the strand, the ultimate load-carrying capacity increased from 18% to 39% for beams with a 1% fiber volume fraction and from 24% to 50% for those with a 2% fiber volume fraction. This increase is attributed to active stress transfer across the concrete cross-section, which reduces the crack angle from 44° to 34°. The shear cracking load also increased with an increase in fiber dosage, but the post-cracking reserve capacity was reduced. Digital image correlation analysis revealed that strain distribution across the crack was uniformly distributed at all loading stages.

Determining Triaxial Tensile Strength of UHPC for Sustainable Design

Presented By: Trevor Looney
Affiliation: University of Oklahoma
Description: The tensile strength of conventional concrete is often ignored in structural design due to its relative low value when compared to compressive strength. However, when designing ultra-high performance concrete structures, ignoring tensile strength is overly conservative and could lead to inefficient designs. Uniaxial tensile data is available for UHPC mix designs, but very little data exists examining the multiaxial tensile strength of the material. To help fill this data gap, an apparatus was designed at the University of Oklahoma capable of applying multiaxial tensile stress states to a cube specimen. A UHPC mixture developed at the University of Oklahoma with fiber contents of 0%, 1%, 2%, 4%, 5%, and 6% by volume was characterized in this apparatus to assess the effect varying the fiber content had on its multiaxial tensile strength. The data collected was compiled and compared to previously published multiaxial compressive UHPC data. This dataset was then used to fit two previously published models with different meridian shapes (parabolic and cubic) to ascertain which shape best describes the failure surface of UHPC in the tensile region.

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