Semester of Graduation

Fall 2024

Degree

Master of Science in Civil Engineering (MSCE)

Department

Civil and Environmental Engineering

Document Type

Thesis

Abstract

Ultra-high performance concrete (UHPC) is a unique type of construction material with exceptional mechanical properties and high durability. This type of material can lead to extended service life and contribute to the sustainability and resilience of civil infrastructure. Over the last several decades, intensive research has been conducted into multifunctional and high-performance cementitious composite materials to promote contemporary infrastructure. Integrating advanced composites like multifunctional UHPC can significantly enhance the performance of structural components. Given the challenges posed by climate change and increasing natural hazards, the ability of structures to self-sense damage and enable timely repairs is one of the desired properties in addressing the inevitable deterioration of concrete infrastructure. Among cutting-edge structural materials, those possessing self-sensing capabilities have garnered considerable interest, particularly for structural health monitoring applications. UHPC typically incorporates steel fibers that potentially form a conductive network to enable piezoresistive sensing properties. However, due to the random dispersion of the steel fibers and the limited percentage of their addition in UHPC, the sensing performance is constrained. This study firstly aims to develop a benchmark UHPC using locally available materials in and around the State of Louisiana in the U.S. Then, this study investigated the feasibility of incorporating economical carbon-based materials, specifically carbon fiber, to enhance the conductive network and facilitate the sensing performance of the samples. The results indicated that the UHPC specimens with carbon fiber incorporated had better mechanical properties than the ones with only steel fiber, whereas all the UHPC specimens with and without the carbon fiber showed self-sensing behavior with measurable piezoresistivity. The sensing performance has enhanced with additional amounts of carbon fiber. Specifically, the UHPC with hybrid 2.5 % steel fibers and 0.5 % carbon fibers exhibits a drastically improved piezoresistivity responsible for amplified stability and reversibility under applied stress while maintaining the satisfied mechanical properties.

Date

8-22-2024

Committee Chair

Yen Fang Su

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Available for download on Sunday, August 22, 2027

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