Towards Development and Implementation of eco2-UHPC: Material Characterization and Applications to Structural Precast Columns
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Authors
Romero, Allan Joseph
Issue Date
2024
Type
Dissertation
Language
Keywords
Bridge Columns , Material Characterization , Precast , Recycled Steel Fibers , UHPC
Alternative Title
Abstract
Ultra-high performance concrete (UHPC) is a rapidly growing construction material with excellent mechanical properties and enhanced ductility, making it a leading material for future infrastructure projects. Currently, UHPC is mainly used in architectural facades and small-scale structural applications, mostly for bridges such as field joints and overlays. One of the main challenges hindering the use of UHPC in large-scale applications is the high material and construction costs associated with the proprietary nature of the robust commercial UHPC mixtures and consequential logistical issues. Moreover, a significant amount of experimental work and research is still needed to fully understand the structural performance and behavior of UHPC and develop the proper design guidelines and codes. To contribute towards addressing some of these challenges, the goal of this doctoral study is to develop a scalable, economical- and ecological-friendly (eco 2 ) UHPC that enables the use of locally sourced along with sustainable components like recycled steel fibers for large-scale production and precast applications. The outcome of this study is new knowledge on eco 2 -UHPC that stems from upscaling the use of local and recycled material with large-scale production mixing, for the first time, to perform both comprehensive material variability and characterization testing with structural prototyping and showcasing using axial and seismic precast eco 2 -UHPC columns. This doctoral study aims to demonstrate the viability and feasibility of eco 2 -UHPC with the following research objectives: (1) perform a comprehensive mechanical characterization of eco 2 -UHPC with recycled steel fibers by investigating the effects of fiber aspect ratio, fiber ratio by volume, and different production methods; (2) examine the scalability of eco 2 -UHPC with wide range of locally sourced and sustainable materials, first through a material variability and mechanical characterization testing, then application to five full-scale axial eco 2 -UHPC columns that vary in reinforcement detailing, fiber type, and fiber ratio; (3) demonstrate large-scale mixing and production of eco 2 -UHPC using actual precast practices and equipment to fabricate and test four eco 2 -UHPC bridge columns with different ABC connections under combined axial and quasi-static lateral cyclic loading; and finally, (4) perform shake table tests to investigate the dynamic behavior of eco 2 -UHPC bridge columns with ABC grouted duct connections. The doctoral study is concluded with key observations and findings with regard to the design, construction, and detailing of UHPC columns that can be the basis for future design guideline documents and specifications.
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Creative Commons Attribution 4.0 International