ORCID Identifier(s)

0000-0002-4506-1419

Graduation Semester and Year

2020

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Nur Yazdani

Abstract

Strengthening deteriorated concrete structures with carbon fiber reinforced polymer (CFRP) has been widely validated through laboratory experiments and field tests. Questions and concerns persist related to the CFRP’s long-term performance and service life, however, thus the main objective of this research was to evaluate its durability under various environmental conditions. This research is divided into four distinct phases. In the first phase, the deterioration trends of CFRP laminate under environmental regimes were evaluated after immersion in water at 23, 45, and 60 °C for periods up to 32 weeks. In the second phase, four prediction models of the long-term performance were completed and calibrated with real data from the field, and the most applicable model was used to evaluate the environmental reduction factor from ACI 440.2R (2017). The third phase involved evaluating the durability performance of externally bonded CFRP concrete beams under environmental conditions, using direct tension pull-off and three-point flexural tests. In the fourth phase, numerical analyses were performed to simulate the flexural test of externally bonded CFRP concrete beams, using ABAQUS, a non-linear finite element software. The numerical analyses were calibrated with the experimental results and other parameters were studied. The environmental reduction factor from ACI 440.2R (2017) was evaluated and compared with five international strengthening guidelines. The comparative results showed that ACI 440.2R (2017) overestimated the tensile strength of CFRP material, which could result in unsafe conditions before the end of the designed service life. Hence, a function to estimate the environmental reduction factor was proposed, and 75% strength retention was anticipated after a service life of 75 years.

Keywords

carbon fiber reinforced polymer (CFRP), laminate, strengthening, durability, environmental reduction factor, prediction, finite element analysis (FEA)

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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