ORCID Identifier(s)

ORCID 0009-0000-2276-2418

Graduation Semester and Year

Summer 2024

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Vistasp M. Karbhari

Abstract

The durability of fiber reinforced polymer composites used in civil infrastructure rehabilitation has become increasingly critical, especially under long-term hygrothermal aging conditions. This study focuses on the results of long-term (up to 6 years) hygrothermal aging of wet layup carbon/epoxy composites and investigates the effects of moisture, as well as accelerated aging at elevated temperatures with varying thicknesses and fabric areal weights. The primary objective is to establish a comprehensive understanding of moisture uptake kinetics and its subsequent effects on the glass transition temperature (Tg), mechanical performance, and the resulting implications for material durability. Four papers form the core of this work: a review of moisture uptake models, an analysis of Tg as a durability characteristic, the development of a two-stage model for moisture and Tg kinetics, and an examination of the effects of various aqueous environments on moisture kinetics, glass transition temperature and mechanical properties. The findings offer insights into the interactions between moisture-induced degradation and cure progression, providing a basis for predicting the long-term performance of FRP composites in real-world applications.

Keywords

Composite materials, Fiber, Durability, Degradation, Hygrothermal aging, Diffusion, Relaxation, Glass transition temperature, Mechanics, Solution, Fickian/non-Fickian

Disciplines

Civil Engineering

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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