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Exploring the Stress-Strain Relationship of Lightweight Concrete to Enhance the Lifecycle Performance of Transportation Highway and Bridges
Structural lightweight aggregate concrete materials have widespread applications in transportation infrastructure, including bridge decks and high-performance pavements. Recent developments in the design and construction of these components have expanded the focus on the stress-strain relationship and elasticity modulus of concrete materials. This project aims to establish a stress-strain relationship for lightweight concrete with applications in high-performance pavements and bridge decks with broadened scope. Further, the project examines the lifecycle effects of the stress-strain relationship on the service life of critical infrastructure like bridges. Moreover, the lifecycle analysis follows the standard practice of communicating the environmental footprints of lightweight concrete bridge decks, including greenhouse gas emissions. This project is aligned with the Federal Highway Administration (FHWA) Every Day Count (EDC-7) Innovations.
Principal Investigator:
Fariborz M. Tehrani, PhD
PI Contact Information:
ftehrani@csufresno.edu
California State University, Fresno
Dates:
March 2025 to March 2026
Implementation of Research Outcomes:
AASHTO (American Association of State Highway and Transportation Officials) has been actively working on updating and refining the modulus of elasticity for lightweight concrete in their bridge design specifications. AASHTO has updated the empirical expression for the modulus of elasticity of lightweight concrete in their LRFD Bridge Design Specifications. These updates aim to better reflect the properties of modern lightweight concrete materials. Although focused on high-strength concrete, recent studies by AASHTO have also provided insights into the modulus of elasticity, shrinkage, and creep of concrete. These studies help improve the accuracy of long-term material property predictions for both high-strength and lightweight concrete. AASHTO provides tools and calculators to compute the modulus of elasticity of concrete based on different design codes, including their own AASHTO-LRFD specifications. This helps engineers and designers accurately determine the elastic properties of lightweight concrete for various applications. This project contributes to a better understanding the stress-strain relationship of lightweight concrete containing lightweight aggregates.
Impacts/Benefits of Implementation:
Research on the modulus of elasticity of lightweight concrete has explored various factors that influence its mechanical properties. Studies have shown that the modulus of elasticity is affected by the type and proportion of lightweight aggregates used, the cementitious matrix, and the presence of fibers or other additives. In practice, the modulus of elasticity of lightweight concrete is crucial for structural design and analysis. Engineers use empirical formulas and guidelines, such as those provided by the American Concrete Institute (ACI) and the Expanded Shale, Clay & Slate Institute (ESCSI), to estimate the modulus of elasticity based on the concrete's compressive strength and density. These guidelines help ensure that lightweight concrete structures meet the required performance standards and safety criteria.
Project Number:
2531
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Contact Us
SJSU Research Foundation 210 N. 4th Street, 4th Floor, San Jose, CA 95112 Phone: 408-924-7560 Email: mineta-institute@sjsu.edu
