Ultra-high performance concrete (UHPC) is the next generation of concrete, a concrete whose mechanical and durability properties far exceed those of conventional concretes. UHPC combines together a set of advancements in concrete technology from recent decades to create a concrete with compressive strengths at or greater than approximately 18 ksi, sustained post-cracking tensile strength at or greater than 750 psi, and a discontinuous pore structure that reduces permeability by an order of magnitude. During the past 15 years, UHPC has found significant usage in the US bridge sector in two primary applications.  UHPC, when used as a field-cast grout connecting prefabricated bridge elements, enables accelerated construction of robust structures. Also, UHPC has been engaged for bridge rehabilitation solutions such as bridge deck overlays, link slabs, and beam end repairs.

As the awareness of UHPC capabilities has grown, interest has turned toward using UHPC for primary structural elements in bridges. The handful of primary structural component deployments in the US so far (e.g., a few pretensioned girders, a few precast bridge decks, a few piles) have been completed as experimental deployments by innovative departments of transportation. Mainstreaming of this technology will require a broader knowledge base and greater standardization of engineering practices.

Researchers at the FHWA Turner-Fairbank Highway Research Center have been leaders in advancing UHPC technology for the bridge sector for more than two decades. This vertically integrated applied engineering research program has enabled UHPC usage by addressing the challenges that come with a new class of structural material, including developing new test methods, drafting new design, construction, and conformance specifications, conducting full-scale tests of novel structural components, and delivering training materials to lessen the barriers adoption.

The successfully completed TPF-5(468) Structural Behavior of Ultra-High Performance Concrete helped enable the delivery of many key work products including:

·         Developed and published FHWA-HRT-23-077 Structural Design with Ultra-High Performance Concrete which contains the draft UHPC structural design framework that FHWA developed and provided to AASHTO Committee on Bridges and Structures’ Concrete Design Subcommittee for their consideration, and that forms the basis of the AASHTO Guide Specification for Structural Design with UHPC.  The report also contains two design examples that help explain the use of the structural design framework.

·         Developed and delivered draft UHPC material conformance guidance at the behest of the AASHTO Committee on Bridges and Structures’ Concrete Design Subcommittee. This guidance addresses Owners’ need for 1) prescriptive UHPC constituent guidance, 2) UHPC material qualification guidance, and 3) UHPC material quality control processes. Through close coordination with the AASHTO Concrete Design Subcommittee over the 2022-2026 timeframe, this draft will be balloted by AASHTO CBS in June 2026 and, if passed, will be integrated in the 2^nd Edition of the AASHTO Guide Specification for Structural Design with UHPC to be published in 2027.

·         Conducted a UHPC mechanical property testing methodology study what will deliver a large body of statistically relevant data from suites of compression and tension test methods. The results from this study underpin the UHPC material conformance guidance that AASHTO is balloting in June 2026.

·         Developed a new quality control test method focused on UHPC tensile properties and worked with the AASHTO Committee on Materials and Pavement’s Hardened Concrete Properties Subcommittee to move the test method from concept to fruition. The AASHTO T 425 Standard Method of Test for Flexural Response of UHPC Prisms in Four-Point Bending will be published in the 2026 edition of AASHTO Standard Specifications for Transportation Materials and Methods of Sampling and Testing.

·         Completed research and published a journal paper on Test Methods for Steel Fiber Segregation in UHPC (DOI: 10.1061/JMCEE7.MTENG-20607). This research delivered a recommended quality control testing methodology that can be used to assess whether the steel fibers in a freshly mixed UHPC will remain suspended or will be susceptible to segregation (sinking) prior to the hardening of the UHPC.

·         Published a report (FHWA-RC-24-0009) focused on short span UHPC bridges, enabling owners to consider different types of UHPC superstructures for common bridges types across the US.

·         Created a workshop training class on Structural Design with UHPC to inform owners, designers, and consultants about the UHPC structural design methodologies that are contained in the AASHTO Guide Specifications for Structural Design with UHPC.  This workshop includes a published manual FHWA-RC-24-0006. 

The objective of the proposed project is to develop knowledge and work products that enable the use of ultra-high performance concrete (UHPC) structural components.

The proposed project focuses on the design, fabrication, performance, and analysis of UHPC structural components. It is anticipated that various UHPC components will be designed, fabricated, and tested. The test results will be analyzed and used to inform proposed UHPC structural design, construction, and material conformance guidance. Results will also be used to support usage of UHPC by interested departments of transportation. It is anticipated that common prefabricated bridge elements (e.g., girders, piles) will be addressed in this study, with behaviors related to flexure, shear, fatigue, and anchorage zones being investigated. Other components and behaviors may be investigated based on available resources and the interest of participating partners.

Funding: The scope of the project is scalable based on the level of funding received. FHWA is already contributing significant resources to the topic area. Entities who are interested in supporting and expanding FHWA’s ongoing efforts should consider contributing funds. In-kind contributions of structural components will also be considered.

In-Person Meetings and Peer Exchanges: Funds may be used to cover travel expenses for staff from contributing agencies to attend in-person meetings or events.

Opportunity to Join: Prospective partners are encouraged to make a financial commitment and join the study whenever able. If the study has already been initiated, please engage the lead study contact for instructions on the process for joining an in-progress study.