Graduation Semester and Year

2023

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Maria Konsta-Gdoutos

Abstract

ABSTRACT: While concrete, the most widely used construction material exhibits low electrical and thermal conductivity, it can be engineered at the nanoscale to exhibit energy-related functionalities. This dissertation aims to develop nanoengineered cementitious composites with high electrical conductivity and tunable thermal conductivity to enable energy-related functionalities such as electricity generation and thermal heating capabilities. Highly dispersed nanostructured materials with different intrinsic properties were used to modify the thermal and electrical properties of the developed cementitious composites to enable their thermoelectric (TE) and/or electrothermal (ET) characteristics. One of the objectives of this research was to optimize the electrical-to-thermal energy conversion capability and efficient thermal energy dissipation of mortars reinforced with highly conductive multi-walled carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs). It was found that the uninterrupted electrical and thermal energy conduction through a continuous network in the cementitious matrix is critical to achieve high electrical and thermal conductivity with negligible energy storage ability and an almost complete conversion of electrical to thermal energy. Another objective of this research was to control the thermal properties while maintaining high electrical conductivity to enable nanocomposites' thermoelectric energy conversion capability. Thermoelectric cement composites developed by merging low amounts of superconducting single-walled carbon nanotubes (SWCNTs) and insulating cellulose nanofibrils (NCFs) in the cementitious matrix, exhibit optimized Seebeck Coefficient and Figure of Merit, the key parameters for generating electrical energy from thermal energy harvesting. The thermal energy harvesting capability and the electrothermal efficiency of the developed cementitious nanocomposites were showcased through laboratory-scale models.

Keywords

Electrothermal cementitious materials, Thermoelectric cementitious materials, Carbon nanotubes, Carbon nanofibers, Energy-related functionalities

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

31778-2.zip (7652 kB)

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