Civil Engineering Reference
In-Depth Information
20
Nanotechnology for eco-efficient concrete
M. S. KonSta-GdoutoS, democritus university of
thrace, Greece
DOI
: 10.1533/9780857098993.4.544
Abstract
:
this chapter discusses the development of a materials science
approach with an application to nanotechnology to optimize the processing
and micro/nanoscale structure of cement-based materials reinforced with
nanosized fibers and carbon nanotubes. The dispersion of multi-walled
carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs) for use in
cementitious composites and specifically the effect of ultrasonication
energy are discussed in detail. the nanomechanical properties of the Cnt/
CNF cementitious nanocomposites are examined through nanoindentation
experiments. Additionally, the excellent reinforcing ability of both the
MWCNTs and CNFs is demonstrated. Finally, the effect of the addition of
silica nanoparticles on the degradation by calcium leaching is discussed and
explained.
Key words
:
carbon nanotubes, carbon nanofibers, nanoindentation,
nanomechanical properties, nanosilica, calcium leaching.
20.1 Introduction
Nanoparticles, carbon nano-fibers (CNFs) and nanotubes (CNTs) offer a
potential for developing new nano-enhanced materials/coatings for dramatically
improving the environmental and energy performance of structural materials
such as concrete. nanomaterials can improve the strength, durability and
adaptability of concrete; reduce material toxicity; improve insulation; and
protect surfaces by applying new processes such as photocatalysis.
the fundamental properties of cementitious materials, such as concrete,
are affected by the material properties at the nanoscale. the construction
industry and research community currently investigates the changes in
nanoscale properties with the addition of different mineral admixtures
and CNFs/CNTs, as well as optimized processing techniques targeting the
development of new materials with specific properties. One major area of
focus is to develop nano-engineered materials with improved properties and
to investigate the changes in the nanostructure, fracture properties, transport
properties and durability of cement-based nanocomposites reinforced with
highly dispersed CNTs and CNFs and/or with the addition of nanosilica.
Silica nanoparticles can be of a great benefit to the transport properties of
concrete since not only are the porosity and the portlandite content of the
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