Publication Date

2017-08-11

Availability

Open access

Embargo Period

2017-08-11

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Civil, Architectural and Environmental Engineering (Engineering)

Date of Defense

2017-07-31

First Committee Member

Ali Ghahremaninezhad

Second Committee Member

Antonio Nanni

Third Committee Member

James Giancaspro

Fourth Committee Member

Qingda Yang

Fifth Committee Member

Edward A. Dauer

Abstract

This study aims to obtain a fundamental understanding of the effect of polymeric materials with distinct functional groups on the nanostructure and nanomechanical response of calcium-silicate-hydrate (C-S-H). Nature has created biological materials with hierarchical microstructure and superior mechanical and functional properties. This is achieved in nature through certain biopolymers with specific structures and functionalities directing growth, microstructure and macroscopic performance of biological materials. C-S-H comprises the primary component of the cement hydration product and plays a fundamental role in determining the mechanical and long-term characteristics of cement-based materials. The different size and molecular structure of polymers, and the complex structure and chemical functionalities of biopolymers permit a wide range of interactions including electrostatic, hydrogen bonding and hydrophobic with C-S-H. The ability to modify the characteristics of C-S-H through a specific combination of interactions with biopolymers permits a pathway to manipulate the structure, and the physical and mechanical properties of C-S-H. The primary contribution of this study is to explore a bio-inspired approach as a new paradigm in controlling microstructure design to achieve desired properties in infrastructure materials. In pursuit of the objectives of this study, this dissertation aims to obtain a fundamental understanding of the interaction of polymers and biopolymers with C-S-H, to discover the effect of polymers and biopolymers on the atomic structure and morphology of C-S-H, and to elucidate how polymers and biopolymers affect the Young’s modulus of C-S-H. This study shows that C-S-H can be used in biomimetic nanocomposites made of inorganic and organic compounds. For the first time a C-S-H/polymer nanocomposite with the aim of investigating the mechanical properties was fabricated using the layer-by-layer (LBL) technique. Because of the presence of inorganic compounds in the structure of the C-S-H/polymer nanocomposite, it has the potential to exhibit much more flexibility than pure C-S-H which is highly desired in construction materials. The outcome of this study can be seen as a first step towards the formation of bio-inspired construction materials.

Keywords

Bio-Inspired Materials; Cementitious Materials; Nanocomposites; Calcium-Silicate-Hydrate; Nanostructural Modifications; Nanomechanical Properties

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