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  • 1. Saurav / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248- 9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.1077-1082 Application Of Nanotechnology In Building Materials Saurav Department of civil engineering, Jaypee University of information technology, Waknaghat, Dist: solan, Himachal Pradesh, India.Pin:173234Abstract In this paper, application of apply nano technology in construction materials,nanotechnology in building materials for various which can exhibit, probably one of the mostcivil engineering works is discussed. Since the use prominent, societal impacts.of nanotechnology controls the matter at theatomic level, the properties of matter are seriously 2. Nanotechnology:affected. Strength, durability and other properties Nanotechnology is the use of very smallof materials are dramatically affected under a pieces of material by themselves or theirscale of nano meter(10-9m).This paper also reveals manipulation to create new large scale materials. Thehow the use of nano technology makes concrete size of the particles is the critical factor. At themore stronger, durable and more easily placed. nanoscale (anything from one hundred or more downDifferent types of nano materials used are to a few nanometres, or 10-9m) material properties arediscussed with its wide applications. altered from that of larger scales. There is a dramatic change in situation and this is what happens at the1. Introduction: scale of nanotechnology. Different things start to Nanotechnology is the use of very small happen at this level e.g. gravity becomesparticles of material either by themselves or by their unimportant, electrostatic forces take over andmanipulation to create new large scale materials. quantum effects get in. Another important aspect isNanotechnology is not a new science and it is not a that, as particles become nano-sized, the proportionnew technology, it is rather an extension of the of atoms on the surface increases relative to thosesciences and technologies that have already been in inside and this leads to change in the properties.development for many years. Nanotechnology is the Knowledge at the nanoscale of the structure andre-engineering of materials by controlling the matter characteristics of materials (otherwise known asat the atomic level. The key in nanotechnology is the characterization) will promote the development ofsize of particles because the properties of materials new applications and new products to repair orare dramatically affected under a scale of nano meter improve the properties of construction materials. For[10-9 meter]. Further, as particles become nano-sized example, the structure of the fundamental calcium-the proportion of atoms on the surface increases silicate-hydrate (C-S-H) gel which is responsible forrelative to those inside and this leads to novel the mechanical and physical properties of cementproperties. Concrete is stronger, more durable and pastes, including shrinkage, creep, porosity,more easily placed, steel tougher and glass self- permeability and elasticity, can be modified to obtaincleaning. Increased strength and durability are also a better durability. It is these “nano-effects”, however,part of the drive to reduce the environmental that ultimately determine all the properties that wefootprint of the built environment by the efficient use are familiar with at our “macro-scale” and this isof resources. This is achieved both prior to the where the power of nanotechnology comes in. If weconstruction process by a reduction in pollution can manipulate elements at the nanoscale we canduring the production of materials (e.g. cement) and affect the macro-properties and produce significantlyalso in service, through efficient use of energy due to new materials and processes.advancements in insulation. Two nano-sized particles Types of nano materials:that stand out in their application to construction i) Titanium dioxide (TiO2)materials are titanium dioxide (TiO2) and carbon ii) carbon nanotubes (CNT’s)nanotubes (CNT’s). The former is being used for its iii) nano silica(ns)ability to break down dirt or pollution and then allow iv) polycarboxilatesit to be washed off by rain water on everything from v) nano Zro2,etcconcrete to glass and the latter is being used tostrengthen and monitor concrete. Owing to many 3. Application of nano technology in buildingunique characteristics of nanotechnology derived materials:products, newly developed nano based products can Many disciplines of civil engineeringsignificantly reduce current civil engineering including design and construction processes can beproblems. Basically, construction deals with high- benefited from nanotechnology. For example, newtech materials and processes that have been use in structural materials with unique properties, lighterconstruction. Hence, there is huge scope to and stronger composites, fire insulator, sound 1077 | P a g e
  • 2. Saurav / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248- 9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.1077-1082absorber, low maintenance coating, water repellents, A further type of nanoparticle, which has remarkablenano-clay filled polymers, self-disinfecting surfaces, properties, is the carbon nano tube (CNT) and currentUN light protector, air cleaners, nano sized sensors, research is being carried out to investigate theultra thin- strong- conductive wafers, solar cells etc to benefits of adding CNT’s to concrete. Carbonname a few. This paper presents, in brief, the areas of nanotubes are a form of carbon that was firstapplication of nanotechnology in civil engineering discovered in Russia but came into use in the lateand the science & technology behind the improved ninety’s in Japan. They are cylindrical in shape, asperformance. Further, the existing challenges that the shown in figure below, and their name comes fromscientists and technologists facing towards exploiting their nanometre diameter. They can be severalthe potentiality of nanotechnology is also brought millimetres in length and can have one “layer” orout. wall (single walled nanotube) or more than one wall (multi walled nanotube). They have 5 times the3.1 Nano technology and concrete: Young’s modulus and 8 times (theoretically 100 Concrete is, a macro-material strongly times) the strength of steel while being 1/6th theinfluenced by its nano-properties and understanding density. The addition of small amounts (1% wt) ofit at this new level is yielding new avenues for CNT’s can improve the mechanical properties ofimprovement of strength, durability and monitoring. samples consisting of the main Portland cementMuch of the analysis of concrete is being done at the phase and water. Oxidized multi-walled nanotubesnano-level in order to understand its structure using (MWNT’s) show the best improvements both inthe various techniques developed for study at that compressive strength (+ 25 N/mm2) and flexuralscale such as Atomic Force Microscopy (AFM), strength (+ 8 N/mm) compared to the referenceScanning Electron Microscopy (SEM) and Focused samples without the reinforcement. It is theorized theIon Beam (FIB). Silica (SiO2) is present in high defect concentration on the surface of theconventional concrete as part of the normal mix. oxidized MWNTs could lead to a better linkageHowever, one of the advancements made by the between the nanostructures and the binder thusstudy of concrete at the nano scale is that particle improving the mechanical properties of thepacking in concrete can be improved by using nano- composite rather like the deformations on reinforcingsilica which leads to a densifying of the micro and bars.nanostructure resulting in improved mechanical In fact, even some of the rules in structuralproperties. Nano-silica addition to cement based concrete design are actually empirically derivedmaterials can also control the degradation of the from observed behaviour Nanotechnology, involvingfundamental C-S-H (calcium-silicate- hydrate) the study of the fundamental components of concretereaction of concrete caused by calcium leaching in can lead the way to a real understanding of concretewater as well as block water penetration and construction and service life based on a designedtherefore lead to improvements in durability. Related material with predetermined properties. This isto improved particle packing, high energy milling of strongly related to the study of service life throughordinary Portland cement (OPC) clinker and standard multiscale modelling (covering multiple dimensionalsand, produces a greater particle size diminution with scales such as from nm to m). As an example of therespect to conventional OPC and, as a result, the kind of additions that have been made to concrete,compressive strength of the refined material is also 4 research has shown that an anaerobic (one that doesto 6 times higher (at different ages). Another type of not require oxygen) microorganism incorporated intonano particle added to concrete to improve its concrete mixing water results in a 25% increase inproperties is titanium dioxide (TiO2).TiO2 is a white 28-day strength. The Shewanella microorganismpigment and can be used as an excellent reflective was used at a concentration of 105 cells/ml andcoating. It is incorporated, as nano particles and it is nanoscale observations revealed that there was aadded to paints, cements and windows for its deposition of sand-cement matrix on its surface. Thissterilizing properties since TiO2 breaks down organic led to the growth of filler material within the pores ofpollutants, volatile organic compounds and bacterial the cement- sand matrix and resulted in increasedmembranes through powerful catalytic reactions. It strength.can therefore reduce airborne pollutants when applied Self Compacting Concrete (SCC) is one thatto outdoor surfaces. Additionally, it is hydrophilic does not need vibration in order to level off andand therefore gives self cleaning properties to achieve consolidation. This represents a significantsurfaces to which it is applied. The process by which advance in the reduction of the energy needed tothis occurs is that rain water is attracted to the surface build concrete structures and is therefore aand forms sheets which collect the pollutants and dirt sustainability issue. In addition SCC can offerparticles previously broken down and washes them benefits of up to 50% in labour costs, due to it beingoff. The resulting concrete, already used in projects poured up to 80% faster and having reduced wear andaround the world, has a white colour that retains its tear on formwork. The material behaves like a thickwhiteness very effectively unlike the stained fluid and is made possible by the use ofbuildings of the material’s pioneering past. polycarboxylates (a material similar to plastic 1078 | P a g e
  • 3. Saurav / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248- 9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.1077-1082developed using nanotechnology). SCC mixes, which Welds and the Heat Affected Zone (HAZ) adjacent tocontain a high content of fine particles, need a very welds can be brittle and fail without warning wheneffective dispersing system in order to be fluid and subjected to sudden dynamic loading, and weldworkable overtime at low water/cement ratio (high toughness is a significant issue especially in zones ofW/C ratios would lead to risk of segregation) and high seismic activity. Weld and HAZ failures led toonly polycarboxylates can meet these requirements. the re-evaluation of welded structural joints in theIn addition, while long term strengths of aftermath of the 1994 Northridge earthquake in theconventionally super plasticized concrete are very Los Angeles area and current design philosophieshigh, the very early strengths, especially in winter, include selective weakening of structures to produceare not high enough for a quick and safe removal of controlled deformation away from brittle weldedformwork and steam curing is therefore used to joints or the deliberate over-sizing of structures toaccelerate the hydration of cement. This can be keep all stresses low. Research currently under way,eliminated in the precast industry through the use of however, has shown that the addition of nanoparticlesthe latest generations of polycarboxylates resulting in of magnesium and calcium makes the HAZ grainsfurther time and energy savings. finer (about 1/5the size of conventional material) in Finally, fibre wrapping of concrete is quite plate steel and this leads to an increase in weldcommon today for increasing the strength of pre- toughness. This is sustainability as well as a safetyexisting concrete structural elements. Advancement issue, as an increase in toughness at welded jointsin the procedure involves the use of a fibre sheet would result in a smaller resource requirement(matrix) containing nano-silica particles and because less material is required in order to keephardeners. These nanoparticles penetrate and close stresses within allowable limits.small cracks on the concrete surface and, instrengthening applications, the matrices form a strong Two relatively new products that arebond between the surface of the concrete and the available today are Sandvik Nanoflex and MMFX2fibre reinforcement. In the strengthening process pre- steel .Both are corrosion resistant, but have differentcut carbon tows (fibres) and sheets impregnated with mechanical properties and are the result of differentthe matrix are placed on the prepared concrete applications of nano technology. Traditionally, thesurface and bonded using grooved rollers. The ability trade off between steel strength and ductility is aof the samples to sustain load after cracking is greatly significant issue for steel; the forces in modernimproved by the carbon tows and both the matrix and construction require high strength, whereas safetythe interface are durable under wetting and drying (especially in seismic areas) and stress redistributionand scaling (scraping) conditions. Additionally, there require high ductility. This has led to the use of lowis no decrease in the maximum load capacity after strength ductile material in larger sizes than wouldrepeated cycles of wetting and drying or scaling. otherwise be possible with high strength brittle material and consequently it is an issue of3.2 Nanotechnology and Steel sustainability and efficient use of resources. Sandvik Steel has been widely available since the Nanoflex has both the desirable qualities of a highsecond industrial revolution in the late part of the 19th Young’s Modulus and high strength and it is alsoand early part of the 20th Century and has played a resistant to corrosion due to the presence of very hardmajor part in the construction industry since that nanometre-sized particles in the steel matrix. Ittime. Fatigue is a significant issue that can lead to the effectively matches high strength with exceptionalstructural failure of steel subject to cyclic loading, formability and currently it is being used in thesuch as in bridges or towers. This can happen at production of parts as diverse as medical instrumentsstresses significantly lower than the yield stress of the and bicycle components, however, its applicationsmaterial and lead to a significant shortening of useful are growing. The use of stainless steel reinforcementlife of the structure. The current design philosophy in concrete structures has normally been limited toentails one or more of three limiting measures: a high risk environments as its use is cost prohibitive.design based on a dramatic reduction in the allowable However, MMFX2 steel, while having thestress, a shortened allowable service life or the need mechanical properties of conventional steel, has afor a regular inspection regime. Stress risers are modified nano-structure that makes it corrosionresponsible for initiating cracks from which fatigue resistant and it is an alternative to conventionalfailure results and research has shown that the stainless steel, but at a lower cost.addition of copper nanoparticles reduces the surfaceunevenness of steel which then limits the number of 3.3 Nanotechnology and Woodstress risers and hence fatigue cracking. Carbon nanotubes are a new discovery,Advancements in this technology would lead to whereas wood is an ancient material which has beenincreased safety, less need for monitoring and more used since the dawn of civilization. However,efficient materials use in construction prone to perhaps not surprisingly given nature’s evolutionaryfatigue issues. process, wood is also composed of nanotubes or “nanofibrils”; namely, lignocellulosic (woody 1079 | P a g e
  • 4. Saurav / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248- 9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.1077-1082tissue) elements which are twice as strong as hydrophilic nature of the building material. Thenanofibrils would lead to a new paradigm in essential requirements waterproofing materials aresustainable construction as both the production and • Resistance it can impart to water absorption.use would be part of a renewable cycle. Some • Preventing of water soluble salts, particularlydevelopers have speculated that building chloride salts.functionality onto lignocellulosic surfaces at the nano • Penetration of waterproofing treatment to ascale could open new opportunities for such things as measurable depth.self-sterilizing surfaces, internal self-repair, and • Non-staining of treated surface areas.electronic lignocellulosic devices. Due to its natural • Long-term stability in an alkaline environment.origins, wood is leading the way in cross-disciplinary • Low environmental and health risk.research and modelling techniques. Firstly, BASF • UV stability (20+ years).have developed a highly water repellent coating There are two classes of waterproofing products:based on the actions of the lotus leaf as a result of the a). Film Formersincorporation of silica and alumina nano particles and b). Penetrantshydrophobic polymers. And, secondly, mechanical Film Formers: The economics and the easestudies of bones have been adapted to model wood, of application have led to widespread use of filmfor instance in the drying process. forming water repellents. The products like acrylic paint, silicon polymers are commonly3.4 Nano technology in waterproofing building used in the world for waterproofingmaterials application. These film formers have particle Waterproofing of building materials has size greater than 100 nm, which will notbeen a problem since last 1000 years. The problem allow them to penetrate inside the pores of thehas not been addressed completely due to lack of building materials but form a film covering andunderstanding at nano level of the building material. preventing the surface from water absorption.The new development in science & technology has Generally, these polymer films are hydrophobic butallowed using the latest nano technology to produce they need to be continuous and defect-free and alsoeco-friendly Organo-Silicon products to waterproof must be UV resistant. It is found that duringpractically all the different kinds of building application ensuring continuous film on roughmaterials. The nano technology has ensured that surface is not easy which leads to weak points forservice life of this approach will lead to life cycles film former. All the typical polymer films tend tobeyond 20 to 30 years at very economical cost. break down under UV leading to cracking of theBuilding materials are known to have water seepage, films in 2-5 years, which leads to failure in terms ofwater leakages due to inherent porosity and losing of hydrophobicity and water repellency.microcracks.Waterproofing is a treatment, which is Penetrants: Most penetrants are solvent based,expected to make the material impervious to water. soluble monomeric material with less than 6nm size.Lots of technology and product development has They easily penetrate inside the pores and sub-taken place in various waterproofing products for the branches of the pores. There are two types oflast 50 years, particularly using polymeric backbone penetrants i.e. non reactive and reactive. Non-and variety of other materials. Another serious reactive penetrants are oils and other low viscosityissue waterproofing addresses is to prevent loss hydrophobic material, which coats the pore of theof structural strength of concrete building substrates, and provide water repellency. However,materials, particularly due to ASR (alkali silica these types of materials are also biodegradable andreaction), acid rain, sulphate attacked. It also prevents loose hydrophobicity within a year. Additionally,chloride penetration which can result in corrosion of these products also provide food for mold or fungusthe reinforced steel bars. growth. The reactive penetrants chemically react with the substrate and provide molecular level3.4.1 Water related problems: Most of the hydrophobicity to the treated surface and 3-5mmbuilding materials are very porous and have surface deep in the substrate. Therefore, these types ofhydroxyl groups. These hydroxyl groups attract waterproofing products provide protection for awater because of the hydrophilic nature and similarity very long period. Additionally, the product is boundwith the structure of water. Therefore, most of the chemically on a molecular level to the substrate as abuilding material easily wet and absorb water in the result; weathering (UV radiation) and naturalpores. The size of the water molecule is 0.18 nm (i.e. abrasion have virtually no effect and hence very0.00018 microns).The size of the pores in most of the limited effect on the waterproofing characteristics.building materials, range from 5 to 200 nm. The size Experimentally it has been seen that Silane basedof most of the pollutants like acids, chlorides & waterproofing products are desirable for long-termsulphates would range between 1 to 2 nm. Even with performance. Silanes and Silane/Siloxanes are knownthe dense concrete and stones the pore size is much as new class of waterproofing products. Theselarger than water allowing easy entry with the products are used in USA and Europe for last 30 years. However only last few years they became 1080 | P a g e
  • 5. Saurav / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248- 9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.1077-1082available in India. The solvent based silane The compressive strength results of serieswaterproofing compounds are proven to provide long C0 and N mixtures are shown in Comparison of thelasting performance and are used very widely in USA results from the 7, 28 and 90 days samples shows thatand Europe. The various alkyl silanes that are used the compressive strength increases with nano-ZrO2for waterproofing are (i) isobutyltrialkoxysilane particles chemical up to 1.0% replacement (N2) and(ii) n-octyltrialkoxysilane. Silanes are monomeric then it decreases, although the results of 2.0%materials. The products used for waterproofing are replacement (N4) is still higher than those of theknown as alkylalkoxysilane. Most building materials plain cement concrete (C0). It was shown that the usecontains hydroxyl (OH) group. These OH groups of 2.0% nano-ZrO2 particles decreases thecan chemically react with alkoxy groups of Silane compressive strength to a value which is near to theforming permanent siloxanes bonds with the control concrete. This may be due to the fact that thesubstrate. The alkyl group R’ provides quantity of nano-ZrO2 particles (pozzolan) present inhydrophobicity (water repellency) to the surface. the mix is higher than the amount required toTherefore, these types of products impart water combine with the liberated lime during the process ofrepellency by modifying surface characteristics from hydration thus leading to excess silica leaching outhydrophilic to hydrophobic. and causing a deficiency in strength as it replaces part of the cementitous material but does not contribute to3.5 Nano technology and self healing concrete: strength. Also, it may be due to the defects generated Experimentation is also underway on self- in dispersion of nanoparticles that causes weak zones.healing concrete. When self-healing concrete cracks,embedded microcapsules rupture and release a Sample Nano ZrO2 Compressive strength(Mpa)healing agent into the damaged region through designatio Particlecapillary action. The released healing agent contacts n (%) 7 days 28 91 daysan embedded catalyst, polymerizing to bond the dayscrack face closed. In fracture tests, self-healedcomposites recovered as much as 75 percent of their C0 0 27.3 36.8 42.3original strength. They could increase the life of N1 0.5 31.6 42.7 46.5structural components by as much as two or three N2 1.0 33.1 43.6 48.1times. When cracks form in this self-healing N3 1.5 32.2 42.9 47.7concrete, they rupture microcapsules, releasing a N4 2.0 28.5 39.7 44.3healing agent which then contacts a catalyst,triggering polymerization that bonds the crack closedfig2. 5. Nano technology and green building Nanotechnology, the manipulation of matter at the molecular scale, is bringing new materials and new possibilities to industries as diverse as electronics, medicine, energy and aeronautics. Our ability to design new materials from the bottom up is impacting the building industry as well. New materials and products based on nanotechnology can be found in building insulation, coatings, and solar technologies. Work now underway in nanotech labs will soon result in new products for lighting, structures, and energy. In the building industry, nanotechnology has already brought to market self- cleaning windows, smog-eating concrete, and many other advances. But these advances and currently available products are minor compared to those incubating in the world’s nanotech labs today. There, work is underway on illuminating walls that change colour with the flip of a switch, nanocomposites as thin as glass yet capable of supporting entire buildings, and photosynthetic surfaces making any building facade a source of free energy.Fig2: Mechanism of self healing concrete4 Strength comparisons: 1081 | P a g e
  • 6. Saurav / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248- 9622 www.ijera.com Vol. 2, Issue5, September- October 2012, pp.1077-10826. Concluding remarks and Perspectives for disposal practices and associated recycling, reuse,the Future. and remanufacturing initiatives that enhance the The application of nanotechnology in sustainability of both the nanotechnology andconstruction presents a myriad of opportunities and construction industries.challenges. The use of micro nano materials (MNMs)in the construction industry should be considered not References:only for enhancing material properties and functions (a) M.C.Roco, R.S. Williams,and P. Alivisatos,but also in the context of energy conservation. This is Nanotechnology Research Directions:a particularly important prospect since a high IWGN Research Report.percentage of all energy used) is consumed by (b) ARI News,“Nanotechnology incommercial buildings and residential houses Construction–one of the Top Ten Answers(including heating, lighting, and air conditioning). to World’sBiggestProblems.”2005,Opportunities for energy savings (other than using www.aggregateresearch.com.MNMs to harvest solar or other forms of renewable (c) Y.Akkaya,S.P Shah, M.Ghandehari ,energy) include improved thermal management by “Influence of Fiber Dispersion on theusing silica nano particles in insulating ceramics and Performance of Microfiber Reinforcedpaint/coating that enable energy conservation and Cement Composite” ACI Specialsolar-powered self-cleaning nano-TiO2-coated Publications 216:Innovations in Fiber-surfaces. Additional opportunities include the use of Reinforced Concrete for Value,SP-216-1,QDs and CNTs to improve the efficiency of energy vol.216, 2003,pp.1-18.transmission, lighting, and or heating devices, as well (d) N. Gupta and R. Maharsia, “Enhancementas incorporation of fullerenes and graphene to of Energy Absorption in Syntactic Foamsenhance energy storage systems such as batteries and by Nanoclay, Incorporation for Sandwichcapacitors that harvest energy from intermittent, Core Applications”, Applied Compositerenewable sources (e.g., solar and Materials, Vol. 12, 2005,pp. 247–261wind).Furthermore, MNMs that extend the durability (e) F.Gao, “Clay/Polymer Composites: theof structures (e.g., through enhanced resistance to Story” Materials Today, 2004, pp.50-55.corrosion, fatigue, wear, and abrasion)also contribute (f) M. Aui, and C.P.Huang, The Chemistry andindirectly to saving energy that would otherwise be Physics of Nano-Cement. Report submittedused to repair or replace deteriorated infrastructure. to NSF-REU,University of Delaware,MNMs can also contribute to a greener construction 2006.industry when used as substitutes for materials that (g) Abell A B, Willis K L and Lange D A 1999can become harmful environmental pollutants, such Mercury Intrusion Porosimetry and Imageas lead and mercury. In addition to prevention of nalysis of Cement-Based Materials, J.potential exposure and resulting hazardous impacts, Colloid Interface Sci. 211: 39–44such replacement facilitates handling and waste (h) Baierlein R 2003 Thermal physics.management. MNMs as proxy additives include iron Cambridge University Press. ISBN 0-521-oxide nano particles for lead (as pigment) in paint 658381and silica nano particles for polychlorinated biphenyl (i) Bjornstrom J, Martinelli A, Matic A,(PCB) insulators in electrical devices. Contamination Borjesson L and Panas I 2004 Acceleratingdue to disposal of mercury containing devices, such effects of colloidal nano-silica for beneficialas fluorescent bulbs, flow meters, pressure gauges, calcium–silicate–hydrate formation inand thermostats, can be mitigated by using QD-based cement, Chem. Phys. Lett. 392(1–3): 242–light-emitting diodes (LEDs) and CNT or ZnO 248nanowire-based sensors. As new materials are (j) Bosiljkov V B 2003 SCC mixes with poorlydesigned and brought into use, it is important to graded aggregate and high volume ofunderstand their potential mobility and impacts in limestone filler, Cem.Concr. Res. 33(9):and across air, water, soil, and biota. Advanced 1279–1286analytical capabilities are among the first priorities to (k) B. Bhuvaneshwari et al Nanoscience todetect and characterize MNMs (released from or Nanotechnology for Civil Engineering –incorporated into construction materials) at Proof of Conceptsenvironmentally relevant concentrations within the (l) surinder mann, a report on nanotechnologycomplex environmental and biological matrices. and construction, institute ofEnvironmentally responsible lifecycle engineering of nanotechnology 2006MNMs in construction also needs to be prioritized. (m) Ali nazari et al, Effects of CuOOverall, beyond the current excitement about the nanoparticles on compressive strength ofpossibilities of MNMs to enhance our infrastructure, self-compacting concrete, Sadhana Vol. 36,there are reasonable concerns about unintended Part 3, June 2011, pp. 371–391, 2010consequences. This underscores the need to supportresearch into safe design, production, use, and 1082 | P a g e