UHPC Mixture Design for Accelerated Bridge Construction

Project Details









Remy Lequesne


Kansas Department of Transportation


Accelerated bridge construction, Girders, Mechanical properties, Mix design, Precast concrete, Shrinkage, Ultra high performance concrete

Project description

Engineers at the Kansas Department of Transportation aim to use accelerated bridge construction (ABC) techniques on a bridge currently scheduled for construction in 2022. This approach to construction results in a need for long and narrow closure strips between adjacent precast girders. The concrete used for these closure strips must (1) be strong enough to allow short (e.g. 6 in.) reinforcement lap splices, (2) gain strength rapidly to allow the new bridge to open days after the last concrete placement, and (3) exhibit relatively little shrinkage to limit crack widths along the joint between the closure strips and precast members. Ultra-high performance concrete (UHPC) is a class of materials suitable for this application; UHPC has high compressive and tensile strengths and gains strength rapidly, satisfying two of the three criteria listed above. However, UHPC is also typically sourced from vendors that consider the mixture design proprietary. Some UHPC mixtures also exhibit significant shrinkage, rendering some mixtures unsuitable for the intended purpose of this project. There is a need for a non-proprietary UHPC mixture design that exhibits relatively little shrinkage for use in upcoming KDOT projects. The scope of this project includes trial-batching non-proprietary UHPC mixture designs reported by others (making modifications as necessary), experimenting with methods for reducing shrinkage, measuring fresh-state properties to ensure workability, measuring the mechanical properties of hardened concrete (including the rate of strength gain and the tensile and compressive strengths), and delivering final mixture design recommendations by early summer 2021.