International Journal of Basic and Applied Research Special Vol. 04 (146-151)
Print ISSN - 2249-3352 Online ISSN-2278-0505
Nanotechnology for Building Material P. V. Khandve Dept.of Civil Engineering,Prof. Ram Meghe College of Engineering and Management, Badnera-Amravati, e-mail:
[email protected] Abstract : Nanotechnology is one of the most active research areas with both novel science and useful applications that has gradually established it in the past two decades. The recent researches on nanomaterials and nanotechnologies have highlighted the potential use of these materials in various fields such as medicine, construction, automobile industry, energy, telecommunications and informatics. This is due to the special characteristics of materials at the nano scale. It has been demonstrated that nanotechnology generated products have many unique characteristics, and can significantly fix many field problems. Changes in building material properties is one of the main beneficiaries area of these researches, with applications that will improve the characteristics of building material such as concrete, steel, glass and insulating materials etc. Many current construction problems and requirement of construction process can be enhanced using nanotechnology. In this paper various practically applicable nanotechnology based products that can improve the overall competitiveness of the construction industry are given. The areas of applying nanotechnology in construction are mainly focusing on lighter and stronger structural composites, low maintenance coating material, enhanced properties of cementitious materials, reducing the thermal transfer rate of fire retardant and insulation material and other construction related nano-sensors. The use of nanomaterials in the composition of some materials, such as cement, will result in significant reductions of CO2 pollution and the use of performance thermal insulations will result in efficient use of energy. Thus applications of nanotechnology in civil engineering building material industry are numerous. Some of the applications are elaborated here. Keywords: Nanotechnology, Nanomaterials, Construction, Building Material,
1. INTRODUCTION Nanotechnology is concerned with objects between 1 and 100nm in size. 1 Nanometer = 1 x 10-9m. The nanotechnologies can be defined as the design, characterization, production and application of structures, devices and systems by controlling shape and size at the nanoscale. Nanotechnology requires advanced imaging techniques for studying and improving the material behavior and for designing and producing very fine powders, liquids or solids of materials with particle size between 1 and 100 nm, known as nanoparticles (Gogotsi, 2006).
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Nanomaterials can be defined as those physical substances with at least one dimension –9 between 1…150 nm (1 nm = 10 m). The nanomaterials properties can be very different from the properties of the same materials at –6 –6 –3 micro (10 m) or macro scale (10 …10 m). The nanoscience represents the study of phenomena and the manipulation of materials at nanoscale and is an extension of common sciences into the nanoscale. Nanotechnology is the creation of materials and devices by controlling of matter at the levels of atoms, molecules, and supramolecular (nanoscale) structures (Roco et al., 1999). In other words, it
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is the use of very small particles of materials to create new large scale materials (Mann, 2006). Nanotechnology is the engineering of functional systems at the molecular scale. Nanotechnology is the use of very small particles of material either by themselves or by their manipulation to create new large scale materials. Nanotechnology is not a new science and it is not a new technology. It is rather an extension of the sciences and technologies. The technology enables us to develop materials with improved properties or it can be used to produce a totally new material. Nanotechnology -9 deals with particle at nano-scale, i.e., 10 m. At “nano scale” the world is different from “macro scale”, e.g., the gravity becomes unimportant, electrostatic forces take over and quantum effects emerge. As particles become nano-sized, the proportion of atoms on the surface increases relative to those inside leads to “nano-effects”, however, that ultimately determine all the properties that we are familiar with at our “macro-scale” and this is where the power of nanotechnology comes in. Following are the major application of nanotechnology in the field of (i) Nano-medicine, (ii) Environment, (iii) Energy, (iv) Nano-batteries, (v) Information and communication, (vi) Heavy industry etc. In recent years nanotechnology is also gaining popularity in the field of Civil Engineering and construction. The paper reviews the state of the art “application of nanotechnology for building construction material”. The purpose of this paper is to inform needs associated with nanotechnology, to support and to communicate these nanotechnology science issues to stakeholders and the public. This paper is part of the first stage of research to introduce and emphasize the use of nanomaterials in construction.
objects and structure in a size in the range of 1 and 100nm. Applications of nano technology in civil engineering are numerous. Some of the a p p l i c a t i o n s a r e e l a b o r a t e d b e l o w. Nanotechnologies are the engineered convergence of biology, chemistry, and informatics on a nanoscale that is, involving materials measured in billionths of a meter. The products of these efforts are called nanomaterials, consisting of nanoparticles (having one or more dimensions of 1 to 100 nanometers) and the grouping of these particles into structures that may be larger than nanoscale. Nanoscale materials dissolve in different ways, take on different magnetic properties, react differently to chemicals, or reflect light differently from the way they would at normal size. The use of nanomaterials in construction industry is restricted due to following reasons: i) the lack of knowledge concerning the suitable nanomaterials for construction and their behavior; ii) the lack of specific standards for design and execution of the construction elements using nanomaterials; iii) the reduced offer of nanoproducts; iv) the lack of detailed information regarding the nanoproducts content; v) high costs; vi) the unknowns of health risks associated with nanomaterials. Nanomaterials for Building Construction Nanotechnology can generate products with many unique characteristics that can improve the current construction materials: lighter and stronger structural composites, low maintenance coatings, better cementitious materials, lower thermal transfer rate of fire retardant and insulation, better sound absorption of acoustic absorbers and better reflectivity of glass (Lee et al., 2010). Because the size of the particles is a critical factor, the material properties significant differ at the nanoscale from that at larger scales. Physical phenomena begin to occur differently below the boundary limit: gravity becomes unimportant, electrostatic forces and quantum effects start to prevail. At the same time, the proportion of
2. Material and Methodology Nanotechnologies are worldwide regarded as key technologies for innovations and technological progress in almost all branches of economy. Nano-technologies refer to the target oriented technical utilization of
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International Journal of Basic and Applied Research atoms on the surface increases relative to those inside creating so-called “nano-effect”. All these nano-properties actually affect the materials behavior at macro-scale and, from this point, the power of nanotechnology is emphasized: if the elements are proper manipulated at the nanoscale, the macroproperties are affected and new materials and processes can be developed (Ge & Gao, 2008). Some of the important nanomaterials with potential use in construction industry are discussed here. Nanotechnologies for Concrete Concrete is a macro-material strongly influenced by its nano-properties. The addition of nano-silica (SiO2) to cement based materials can control the degradation of the calciumsilicatehydrate reaction caused by calcium leaching in water, blocking water penetration and leading to improvements in durability (Mann, 2006). The addition of small amounts (1%) of carbon nanotubes can improve the mechanical properties of mixture samples of portland cement and water. Oxidized multiwalled nanotubes show the best improvements both in compressive strength and flexural strength compared to the reference samples. Addition of nanoscale materials into cement could improve its performance. Use of nanoSiO2 could significantly increase the compressive for concrete, containing large volume fly ash, at early age and improve pore size distribution by filling the pores between large fly ash and cement particles at nanoscale. The dispersion/slurry of amorphous nanosilica is used to improve segregation resistance for self-compacting concrete. It has also been reported that adding small amount of carbonnanotube (1%) by weight could increase both compressive and flexural strength. Nanotechnologies for Steel Steel is a major construction material. Its properties, such as strength, corrosion resistance, and weld ability, are very important for the design and construction. It is possible to develop new, low carbon, high performance steel (HPS). The new steel was developed with higher corrosion-resistance and weld ability by
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incorporating copper nanoparticles from at the steel grain boundaries. The addition of copper nanoparticles reduces the surface unevenness of steel which then limits the number of stress risers and hence fatigue cracking, leading to increased safety, less need for monitoring and more efficient materials use in construction subjected to fatigue issues (Mann, 2006). Vanadium and molybdenum nanoparticles improve the delayed fracture problems associated with high strength bolts, reducing the effects of hydrogen embrittlement and improving the steel micro-structure. The addition of nanoparticles of magnesium and calcium leads to an increase in weld toughness. Nanotechnologies for Wood Wood is composed of nanotubes or “nanofibrils”. Lignocellulosic surfaces at the nanoscale could open new opportunities for such things as selfsterilizing surfaces, internal self-repair, Highly water repellent coatings incorporating silica and alumina nanoparticles and hydrophobic polymers are proper to be used for wood. Nanotechnologies for Glass The use of TiO2 nanoparticles to glasses leads to so-called self cleaning technology. Due to the nanoparticles photocatalytic reactions, the organic pollutants, volatile organic compounds and bacterial membranes are decomposed. As well, TiO2 being hydrophilic, his attraction to water forms drops which then wash off the dirt particles decomposed in the previous process. Fireprotective glass is obtained using fumed silica (SiO2) nanoparticles as a clear interlayer sandwiched between two glass panels which turns into a rigid and opaque fire shield when is heated. Nanotechnologies for Coatings and Paitings Nanotechnology is applied to paints in order to assure the corrosion protection under insulation since it is hydrophobic and repels water from the metal pipe and can also protect metal from salt water attack. Others applications refer to coatings that have self healing capabilities through a process of “selfassembly”. In addition to the self-cleaning 148
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International Journal of Basic and Applied Research coatings mentioned above for glazing, the remarkable properties of TiO2 nanoparticles are put to use as a coating material on roadways in tests around the world (Mann, 2006). TiO2 is used to coat glazing because of its sterilizing and anti fouling properties. The TiO2 will break down and disintegrate organic dirt through powerful catalytic reaction. Furthermore, it is hydrophilic, which allow the water to spread evenly over the surface and wash away dirt previously broken down. Other special coatings also have been developed, such as anti-fraffiti, thermal control, energy sawing, anti-reflection coating. Nanotechnologies for Thermal Insulation Micro- and nanoporous aerogel materials are appropiate for being core materials of vacuum insulation panels but they are sensitive to moisture. As a possible remedy it was produced an ultra-thin wall insulation which uses a hydrophobic nanoporous aerogel structure. Another application of aerogels is silica based products for transparent insulation, which leads to the possibility of superinsulating windows. Micro or nanoelectomechanical systems offer the possibility of monitoring and controlling the internal environment of buildings and this could lead to energy savings. Nanotechnologies for Fire Protection Fire resistance of steel structures is often provided by a coating produced by a spray-on cementitious process. Nano-cement made of nanosized particles has the potential to create tough, durable, high temperature coatings. This is achieved by the mixing of carbon nanotubes with the cementious material to fabricate fibre composites that can inherit some of the outstanding properties of the nanotubes. This is achieved by the mixing of carbon nanotubes (CNT's) with the cementious material to fabricate fibre composites that can inherit some of the outstanding properties of the nanotubes such as strength. Polypropylene fibres are also considered as a method of increasing fire resistance and this is a cheaper option than conentional insulation.
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Nanotechnologies for Water Purification Wa t e r p u r i f i c a t i o n u s i n g nanotechnology exploits nanoscopic materials such as carbon nanotubes and alumina fibers for nanofiltration. It also utilizes the existence of anoscopic pores in zeolite filtration membranes, as well as nanocatalysts and magnetic nanoparticles. The adsorption of chlorine concentration is much higher by using nanotechnology as compared to conventional method of purification. Adsorption of chlorine by various media, such as those based on titanium oxide nanowires or palladium nanoparticles are used for analytical detection of contaminants in water samples. It can be used for removal of sediments, chemical effluents, charged particles, bacteria and other pathogens. It is believed that future generations of nanotechnology-based water treatment devices will capitalize on the properties of new nanoscale materials. Nanotechnology in Geotechnical field At nanoscale the inter-particle interaction gains relevance. Nanomaterials possess very high specific surface activity, and chemical activity which is specific surface dependent. High specific surface means high adsorption capacity and great sensitivity of nano-size particles to specific adsorbed materials. Pore fluid characteristics affect the self-assembly of nano-components and their long-term stability. Building clay liners, clay cores, and soil bases using engineered highsurface-area mineral particles consolidated from controlled self assembled clay aggregates to obtain macroscale behavior resulting from exceptional mechanical properties (e.g., very high ductility); external friction control to facilitate compaction while increasing longterm strength, fluidsensitive porous membranes, as well as special and unique chemical properties (e.g., specie-selective diffusion); engineered wetting conditions such as in NanoTurf; altered phase equilibrium for fluids in small pores; and specified electrical properties (e.g., exceptional magnetic and polar properties) are the areas where nanotechnology
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characteristics can, again, significantly fix current construction problems, and may change the requirement and organization of construction process. Use of nanotechonolgy in construction material gives the products that are for: Lighter and stronger structural composites Low maintenance coatingImproving pipe joining materials and techniques. Better properties of cementitious materials Reducing the thermal transfer rate of fire retardant and insulation Increasing the sound absorption of acoustic absorber Increasing the reflectivity of glass 4. Future Challenge While nanotechnology based construction products provide many advantages to the design and construction process, the production of these products, however, require a lot of energy. Also, the nano-tubes might cause a lung problem to construction workers. In other words, it creates an environmental challenge to the construction industry as well. Sustainability and environmental issues caused by growing economic development has gained intensive statewide and worldwide attention. Since the construction industry is heavily involved in the economic development and consumes great amount of resources and energy, its impact on environment is significant. Therefore, it is necessary and urgent to regulate the construction and its related performance to sustainable manners. The nanotechnolgy becomes a double-edge sword to the construction industry. More research and practice efforts are needed with smart design and planning, construction projects can be made sustainable and therefore save energy, reduce resource usage, and avoid damages to environment. It is necessary to establish a system to identify the environmentally friendly and sustainable of construction nanomaterials and to avoid the use of harmful materials in the future. 5. Conclusions Nanomaterials and nanotechnologies have attracted considerable scientific interest due to the new potential uses of particles in
Sensors have been developed and used in construction to monitor and/or control the environment condition and the materials/structure performance. One advantage of these sensors is their dimension (10 -9m to 10-5m). These sensors could be embedded into the structure during the construction process. Smart aggregate, a low cost piezoceramic-based multi-functional device, has been applied to monitor early age concrete properties such as moisture, temperature, relative humidity and early age strength development. The sensors can also be used to monitor concrete corrosion and cracking. The smart aggregate can also be used for structure health monitoring. The disclosed system can monitor internal stresses, cracks and other physical forces in the structures during the structures' life. It is capable of providing an early indication of the health of the structure before a failure of the structure can occur. Nanosensors have a great potential to be used in concrete structures for quality control and durability monitoring. (to measure concrete density and viscosity, to monitor concrete curing and to measure shrinkage or temperature, moisture, chlorine concentration, pH, carbon dioxide, stresses reinforcement corrosion or vibration). Carbon nanotubes increase the compressive strength of cement mortar specimens and change their electrical properties which can be used for health monitoring and damage detection. 3. Advantages of Nanotechnology in Building Construction Nanotechnology can be used for design and construction processes in many areas since nanotechnology generated products have many unique characteristics. These
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International Journal of Basic and Applied Research nanometer scale and, consequently, large amount of funds and effort have being utilized. Even though construction materials may constitute only a small part of this overall effort, it could pay enormous rewards in the areas of technological breakthroughs and economic benefits. Although today the total market share of nano products for construction is small and deemed to be applied in niche markets, this share is expected to grow in the near future, and nanoparticles to play an important role as a basis for the design, development and production of materials construction industry. Following the synthesis achieved in this paper, it can be concluded that the use of nanomaterials in construction is viable in four major directions of development: structural concrete; real time structural monitoring; coatings and paintings; thermal insulations. REFERENCES [1] ARI News (2005). “Nanotechnology in Construction – One of the Top Ten Answers to World's Biggest Problems.” www.aggregateresearch.com/article.asp id=6279, June 1, 2007. [2] Balaguru, P. N. (2005), Proceedings of the International Conference – Application of Technology in Concrete Design, Scotland, UK, p.113-122. [3] Bigley C. and Greenwood P. (2003). Concrete, vol. 37, no. 2, p.43-45 [4] Dhir, R. K., Newlands, M. D., and Csetenyi, L. J. (2005). “Introduction.” Proceedings of the International Conference – Application of Technology in Concrete Design, Scotland, UK, p. IV. [5] Kuennen, K. (2004). “Small Science Will Bring Big Changes To Roads.” Better Roads Li, G. (2004). Cement and Concrete Research, vol.34, p.10431049. [6] Liu, R., Zhang, Z., Zhong, R.; Chen, X.; Li, J.(2007) “Nanotechnology Synthesis Study: Research Report” Mann, S. (2006). “Nanotechnology and Construction,” Nanoforum Report. www.nanoforum.org, May 30, 2008. MMFX Steel Corp. http://www.
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