Innovative Developments of Advanced Multifunctional Nanocomposites in Civil and Structural Engineering

Kenneth Loh, Satish Nagarajaiah

• Publisher: Woodhead Publishing
• Year: 2016
• Print ISBN: 9781782423263
• eBook ISBN: 9781782423447
• Topic: Technology & Engineering
• Subtopic: Construction & Architectural Engineering
• Index: Technology & Engineering

Innovative Developments of Advanced Multifunctional Nanocomposites in Civil and Structural Engineering focuses on nanotechnology, the innovation and control of materials at 100 nm or smaller length scales, and how they have revolutionized almost all of the various disciplines of science and engineering study.In particular, advances in synthesizing, imaging, and manipulating materials at the nano-scale have provided engineers with a broader array of materials and tools for creating high-performance devices. Nanomaterials possess drastically different properties than those of their bulk counterparts mainly because of their high surface-to-mass ratios and high surface energies/reactivity. For instance, carbon nanotubes have been shown to possess impressive mechanical strength, stiffness, and electrical conductivity superior to that of bulk carbon.Whilst nanotechnology has become deeply rooted in electrical, chemical, and materials engineering disciplines, its proliferation into civil engineering did not begin until fairly recently. This book covers that proliferation and the main challenges associated with the integration of nanomaterials and nano-scale design principles into civil and structural engineering.- Examines nanotechnology and its application to not only structural engineering, but also transportation, new infrastructure materials, and the applications of nanotechnology to existing structural systems- Focuses on how nanomaterials can provide enhanced sensing capabilities and mechanical reinforcement of the original structural material- Analyzes experimental and computational work carried out by world-renowned researchers

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Introduction to advanced nanocomposites in civil, structural, and construction engineering

Kenneth J. Loh^1,2, and Satish Nagarajaiah^{3 1}University of California-Davis, Davis, CA, USA ²University of California-San Diego, La Jolla, CA, USA ³Rice University, Houston, TX, USA

Abstract

Technological and material advancements were associated with every period of human history. A key turning point of modern history is the development of concrete and cementitious composites, which permitted the construction of large-scale civil infrastructure systems that serve as the foundation of society today. More recently, the need for achieving higher performance led to various innovations in advanced materials for civil, structural, and construction engineering. This book surveys some of the major work related to using nanotechnology for improving the performance of cement composites, pavement, and structural coatings. In particular, the trend is to transform conventional materials into ones that are multifunctional, where they not only preserve their load-carrying capabilities but also incorporate other desirable features, such as self-sensing, energy dissipation, self-heating, and/or self-healing, among many others.

Keywords

Cementitious composite; Coating; Engineering material; Multifunctional; Nanotechnology; Pavement

1.1. Historical perspectives

Advances in civil, structural, and construction engineering materials are one of the crucial prerequisites for the growth and expansion of human civilizations. Ancient civilizations transformed their knowledge of materials and engineering principles to build some of the greatest civil engineering marvels. The Egyptian Pyramids, Greek Temple of Artemis, Roman aqueducts, and Great Wall of China are just a few among a long list of impressive structures that mark the state of advancement and prosperity of their times. It should be recognized that the discovery and development of appropriate building materials (e.g., mortar, mud mixed with straw, and volcanic sand, among others) made these structures possible. In addition, technological and material advancements were associated with every period of human history, such as during the Middle Ages, Renaissance, and First and Second Industrial Revolutions, among others.

From the perspectives of civil, structural, and construction engineering, it can be argued that one of the key historical turning points of modern history dates back to 1824 with the invention of Portland cement by Joseph Aspdin (Hewlett, 1998). It was found that this material hardens and crystallizes to give it impressive strength. The incorporation of aggregates thereafter to create concrete, which is characterized by greater compression strengths, served as the foundation for building large-scale structures. However, it was not until the mid-nineteenth century when reinforced concrete (RC) was invented; this composite material incorporated steel reinforcement bars that provided tensile load-carrying capacity to complement the surrounding concrete's high compressive strength (Slaton, 2001). The invention of RC and other related civil, structural, and construction engineering advancements paved the way for the construction of various modern civil engineering marvels, such as the Hoover Dam and Panama Canal, to name just a few.

1.2. Multifunctional and multiscale cementitious composites

As societal needs in the late twentieth century drove the demand for higher-performance, sustainable, and resilient infrastructure systems, engineers utilized multiscale design principles for developing innovative cementitious composites. Some notable examples include the development of ultra-high-performance concrete (Wang et al., 2015), fiber-reinforced cementitious composites (FRCCs) (Brandt, 2008), and engineering cementitious composites (ECCs) (Li, 2012), to name a few. These advances embodied multiscale composite material design principles so as to achieve enhanced material performance. In the case of FRCCs and ECCs, greater ductility and strain-hardening behavior were achieved by an improved understanding of micromechanics and the incorporation of microscale fibers in the cement matrix. Not only were mechanical properties enhanced by controlling fiber–matrix interactions, fiber geometries, and fiber materials, but some studies also showed that FRCCs exhibited self-sensing and self-healing properties (Li, 2012).

The advent of new materials and characterization tools in the nanotechnology domain paved the way for the design of next-generation cementitious composites that not only were multiscale but also possessed multiple intrinsic engineering functionalities (i.e., they were multifunctional). Nanotechnology, by definition, entails the incorporation, manipulation, and control of materials with at least one dimension that is less than 100 nm (Poole and Owens, 2003). In particular, since Iijima (Iijima, 1991) discovered carbon nanotubes (CNTs) in 1991 and subsequent characterization studies revealed their impressive multifunctional properties (Baughman et al., 2002), it was only natural that the field shifted toward deriving innovative techniques for creating CNT-enhanced cementitious composites for civil, structural, and construction engineering (Parveen et al., 2013; Sobolev et al., 2006; Konsta-Gdoutos et al., 2010a,b). Like FRCCs and ECCs, these CNT-based cementitious composites sought to leverage the superior intrinsic material properties of CNTs (e.g., their Young's modulus, tensile strength, electrical conductivity, and thermal properties). Although early investigations focused on improving the bulk material's mechanical and fracture properties (Konsta-Gdoutos et al., 2010a,b), other studies explored the possibilities of creating multifunctional load-bearing cementitious composites that are also capable of self-sensing and other relevant properties (Chung, 2012).

1.3. Book outline

This book is structured into three parts that coincide with how nanotechnology has affected three main application areas in civil and construction engineering since the dawn of the twenty-first century.

The first part presents the direct incorporation of carbon-based nanomaterials in cementitious composites to obtain multifunctional construction materials that could not only resist but also self-sense the loads or deformations incurred by the structure. Pioneering work by Sobolev et al. (2006) and Konsta-Gdoutos et al. (2010a,b) demonstrated the possibility of enhancing the properties of cementitious composites, such as concrete, with nanomaterials. This research motivated many researchers to explore other nanomaterials, such as nano-silica and nano-titanium dioxide, as additives for nanomodified concrete to improve the compressive strength and ductility of concrete. CNTs or carbon nanofibers were also used to improve the strength, modulus, and ductility of concrete by modifying the cement properties through nanomodification. CNTs were also used to make the concrete multifunctional, namely, by nano-engineering them with self-sensing, deicing, sound absorption, or damping properties, in addition to their fundamental mechanical or load-bearing property. The chapters presented in the first part of the book present recent developments in this field.

The second part is centered on pavements, which comprise one of the most frequently used civil constructions that is also often overlooked due to its pervasiveness, as well as how they can be nanoengineered for improved performance, damage sensing, self-heating, and durability. Pioneering work by Li et al. (2006, 2007) demonstrated the possibility of using nanoparticles for enhancing the fatigue performance and abrasion resistance of concrete pavement. This research motivated the development of novel cementitious materials with nanoparticles, as well as the use of other nanomaterials, for self-heating and enhanced fatigue properties of pavements. The chapters presented in the second part of the book present recent developments in this field.

The third part of this book examines recent, cutting-edge, technological advancements in nanocomposites and coatings that can be applied onto existing in-service systems or embedded within new civil infrastructure systems for sensing and structural health monitoring (SHM). Pioneering work by Li et al. (2004) and Dharap et al. (2004) demonstrated that nanofilm strain sensors designed using CNTs could sense structural strain response at the macroscale for SHM applications. This research motivated the development of strain-sensitive CNT–polymer nanofilms and nanocomposites that could be rapidly coated onto large structural surfaces or efficiently embedded in infrastructure materials, such as in cement-based materials and fiber-reinforced polymer composite structures. Hou et al. (2007) and Loh (2008) showed that techniques such as electrical impedance tomography, when coupled with multifunctional nanofilms, allowed for sensing strain at every location of the film and enabled damage detection and localization. These CNT-based nanofilms were also utilized to efficiently and effectively modify the cement–aggregate interface of mortar and concrete while achieving spatial structural sensing (Gupta et al., 2015). Most recently, promising noncontact strain-sensing technology has been developed using CNTs (less than 1% by weight), u...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles
• Copyright
• List of contributors
• Woodhead Publishing Series in Civil and Structural Engineering
• 1. Introduction to advanced nanocomposites in civil, structural, and construction engineering
• Part One. Innovative developments of nano-engineered cementitious composites
• Part Two. Innovative developments of nano-engineered pavements
• Part Three. Innovative developments of nanocomposites for in situ damage detection and structural health monitoring
• Index