Development and Implementation of Ultra-High Performance Concrete for Prestressed Bridge Girder Applications

Abstract

The use of ultra-high performance concrete (UHPC) in Texas bridges has the potential to add substantial improvements to bridge construction. Advanced material properties and superior durability of UHPC can result in significant design and construction benefits. Within this context, this research evaluated the application of UHPC for precast, pretensioned bridge girders. The research included a detailed review and synthesis of the relevant literature, development of nonproprietary UHPC mixture designs using locally available materials, material-level experiments for selected UHPC mixtures, fabrication of pretensioned UHPC bridge girder specimens at a precast plant in Texas, transfer length and camber of full-scale UHPC girder specimens, and fiber distribution and orientation analysis. Nonproprietary UHPC mixtures were successfully developed in the laboratory meeting the high early strength requirements (14 ksi within 24 hours) for precast applications with satisfactory mechanical properties and durability performance. Large volume production and girder fabrication were successfully carried out at a precast plant. This dissertation documents the state-of-the-practice and state-of-the-art for UHPC research conducted domestically and internationally, the development of potential nonproprietary UHPC mixtures, optimization of the most promising UHPC mixture using materials from the selected precast plant in Texas, and development of a practical mixing procedure for large volume production in precast plant environments. In addition, this dissertation details the investigation of fresh, hardened, and durability properties of lab-made and plant-made nonproprietary UHPC. Finally, the fabrication of three UHPC girder specimens is documented, along with the analysis of cored samples, to assess fiber distribution and orientation and voids by employing X-ray, infrared, and conventional image analysis techniques.