Saturday, December 4, 2010

Nanomaterial Review in Construction Industry




I am not too sure how the tables will come out here so do go to the source for a better look. In the meantime this gives us a present snapshot of the advent of nano sized technology into even the construction industry.

Essentially industry is waking up to both the benefits and the actual dngers of these new products.  After all, if a particle is small enough, it can actually penetrate cells and by pass ordinary defenses. You do not want to get it wrong.

After all we have experience with asbestosis, silicosis and black lung which all are caused by a flood of small particles in the workplace.  The fact is that small particles of anything represent a significant handling problem and ignoring that is reckless in the extreme.

This is the beginning of an explosion of new useful product that only seems safe to work with.


Nanomaterials in the Construction Industry: A Review of Their Applications and Environmental Health and Safety Considerations
           

Jaesang Lee†, Shaily Mahendra‡ and Pedro J. J. Alvarez†*
† Department of Civil & Environmental Engineering, Rice University, Houston, Texas 77005

‡ Department of Civil and Environmental Engineering, University of California, Los Angeles, California 90095

ACS Nano, 2010, 4 (7), pp 3580–3590
DOI: 10.1021/nn100866w
Publication Date (Web): July 12, 2010

Copyright © 2010 American Chemical Society

* Address correspondence to alvarez@rice.edu.
Abstract

The extraordinary chemical and physical properties of materials at the nanometer scale enable novel applications ranging from structural strength enhancement and energy conservation to antimicrobial properties and self-cleaning surfaces. Consequently, manufactured nanomaterials (MNMs) and nanocomposites are being considered for various uses in the construction and related infrastructure industries. To achieve environmentally responsible nanotechnology in construction, it is important to consider the lifecycle impacts of MNMs on the health of construction workers and dwellers, as well as unintended environmental effects at all stages of manufacturing, construction, use, demolition, and disposal. Here, we review state-of-the-art applications of MNMs that improve conventional construction materials, suggest likely environmental release scenarios, and summarize potential adverse biological and toxicological effects and their mitigation. Aligned with multidisciplinary assessment of the environmental implications of emerging technologies, this review seeks to promote awareness of potential benefits of MNMs in construction and stimulate the development of guidelines to regulate their use and disposal to mitigate potential adverse effects on human and environmental health.

Keywords:

 concrete; windows; sensor; exposure; bioavailability; toxicity; oxidative stress; industrial ecology; risk assessment; labeling

Vocabulary

risk assessment
quantitative determination of risk by calculating magnitude of hazard and probability of exposure to that hazard
industrial ecology
systems-based, multidisciplinary approach to sustainable industrial processes that shift from linear (open loop) systems, in which resource and capital investments move through the system to become waste, to a closed loop system where waste becomes input for new processes
structure−activity relationships
mathematical relationships between a chemical structure and its biological activity
oxidative stress
imbalance between the production of reactive oxygen and a biological system’s ability to readily detoxify the reactive intermediates or easily repair the resulting damage
bioavailability
a measure of the amount of substance/contaminant/drug in a form that produces a biological effect in a target organism

The nanotechnology revolution is making a ground-breaking impact on diverse science, engineering, and commercial sectors, including the construction industry. The physical and chemical properties unique to the nanoscale can lead to remarkable efficacy enhancement in (photo)catalysis, (thermal and electrical) conductivity, mechanical strength, and optical sensitivity, enabling applications such as catalysts, electronic and energy storage devices, advanced mechanical materials, and sensors.(1-4)

Tailing after emerging nanotechnology applications in biomedical and electronic industries, the construction industry recently started seeking out a way to advance conventional construction materials using a variety of manufactured nanomaterials (MNMs)(5-7) (Figure 1). Various MNMs can improve vital characteristics of construction materials such as strength, durability, and lightness,(5, 8, 9) endow useful properties (e.g., heat-insulating, self-cleaning, and antifogging),(10, 11) and function as key sensing components to monitor construction safety and structural health.(12, 13) Despite the current relatively high cost of nanoenabled products, their use in construction materials is likely to increase because of (1) highly valuable properties imparted at relatively low additive ratios, (2) rapid development of new applications harnessing unique nanoscale properties, and (3) decreasing cost of base nanomaterials as they are produced in larger quantities.(14)


Figure 1. Examples of MNM used by the construction industry. (a) Rooftop solar panel (source: National Renewable Energy Laboratory (NREL)). Inset: Arrays of silicon/TiO2 nanowires (source: Lawrence Berkeley National Laboratory (LBNL)). (b) Concrete pavement. Inset: Carbon nanofibers (source: U.S. Department of Transportation Federal Highway Administration). (c) Steel bridge (source: California Department of Transportation). Inset: Copper nanoparticles (source: Air Force Research Laboratory). (d) Building window (source: LBNL). Inset: TiO2 nanoparticles.

The benefits of incorporating MNMs in construction materials could be offset by concerns about their potential to behave as harmful environmental contaminants after their incidental or accidental release. This underscores the need for proactive risk assessment and regulatory guidelines to ensure the safe use and disposal of products containing MNMs.(15)

Use of MNMs in Construction

A variety of MNMs can have beneficial applications in construction that encompass superior structural properties, functional paints and coatings, and high-resolution sensing/actuating devices (Table 1). Selected current and potential uses of MNMs in construction are described below and illustrated in Figure 1.

Balance of paper at source.

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