Building materials of the future1.Introduction:The beginning of civilization as we know it really started with a series of material innovations; the Bronze Age and the Iron Age set us on the path to where we are now, after all. So it makes sense that the history of architecture and civil engineering is also deeply engrained in technological developments of the time. Skyscrapers would have never reached such heights without developments in steel, for example, and facades would have never slimmed down without thin-shell concrete.In a time that is so buzzing with technological development, we cannot help but salivate a little at the material prospects for engineering and finishing works that are just on the horizon. With 2015 just beginning, we want to take a moment to see what drastic innovations may be leaking into the world of civil engineering in the near future.2. Cutting edge building materials:2.1Self-healing concreteThe great downfall of concretethe world's most widely used building materialis unavoidable cracking, caused by exposure to water and chemicals. Butanew developmentfrom a team in the Netherlands could extend the life of this popular material, by infusing it with bacterial sporesthat patch up cracks when water seeps through. Plans are in place to make this self-healing concrete commercial in the next year or two. The Delft group quantified autonomous self-healing ofcontrol samples and compared that to the self-healing capacity of concrete with an inbuilt bacteria-based self-healing agent. While self-healing of 0.2mm wide cracks occurred in 30% of the control samples, complete closure of all cracks was obtained in all bacteria-based samples. Moreover, the crack sealing capacity of the latter group was found to be extended to 0.5mm cracks.

Before-and-after pictures of the surface of a slab of self-healing concrete. The crack is visible in the left-hand image and on the right, the white limestone hasfilled up the gap2.2Nanomaterials

Nanotechnologies for ConstructionNanotechnology can generate products with many unique characteristics that can improve the current construction materials: lighter and stronger structural composites, low maintenance coatings, better cementious 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).Nanotechnologies for ConcreteConcrete 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 calcium-silicatehydrate reaction caused by calcium leaching in water, blocking water penetration and leading to improvements in durability (Mann, 2006).Nano-sensors 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 mortarspecimens and change their electrical properties which can be used for healthmonitoring and damage detection.The addition of small amounts (1%) of carbon nanotubes can improve the mechanical properties of mixture samples of portland cement and water. Oxidized multi-walled nanotubes show the best improvements both in compressive strength and flexural strength compared to the reference samples.Nanotechnologies for SteelThe 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. The carbon nanotubes have little application as an addition to steel because of their inherent slipperiness, due to the graphitic nature, making them difficult to bind to the bulk material (Mann, 2006). Also, the high temperatures involved in the steel elements production process enhances the vibration of carbon atoms significantly, leading to bond breaking and deffects in the nanotubes structure.. Nanotechnologies for WoodWood is composed of nanotubes or nanofibrils. Lignocellulosic surfaces at the nanoscale could open new opportunities for such things as selfsterilizingsurfaces, internal self-repair, and electronic lignocellulosic devices, providing feedback for product performance and environmental conditions during service (Mann, 2006).Highly water repellent coatings incorporating silica and alumina nanoparticles and hydrophobic polymers are proper to be used for wood.. Nanotechnologies for GlassThe use of TiO2 nanoparticles to glasses leads to so-called self cleaning technology. Due to the nanoparticles photocatalytic reactions, the organicpollutants, volatile organic compounds and bacterial membranes aredecomposed. As well, TiO2 being hydrophilic, his attraction to water formsdrops which then wash off the dirt particles decomposed in the previousprocess.Fire-protective glass is obtained using fumed silica (SiO2) nanoparticlesas a clear interlayer sandwiched between two glass panels which turns into arigid and opaque fire shield when is heated.Nanotechnologies for Coatings and PaitingsNanotechnology is applied to paints in order to assure the corrosionprotection under insulation since it is hydrophobic and repels water from themetal pipe and can also protect metal from salt water attack. Others applicationsrefer to coatings that have self healing capabilities through a process of selfassembly.In addition to the self-cleaning coatings mentioned above forglazing, the remarkable properties of TiO2 nanoparticles are put to use as acoating material on roadways in tests around the world (Mann, 2006).

Nanotechnologies for Thermal InsulationMicro- and nanoporous aerogel materials are appropiate for being corematerials of vacuum insulation panels but they are sensitive to moisture. As a Bul. Inst. Polit. Iai, t. LVII (LXI), f. 4, 2011 115 possible remedy it was produced an ultra-thin wall insulation which uses ahydrophobic nanoporous aerogel structure.Another application of aerogels is silica based products for transparentinsulation, which leads to the possibility of super-insulating windows.Micro- or nanoelectomechanical systems offer the possibility ofmonitoring and controlling the internal environment of buildings and this couldlead to energy savings.Nanotechnologies for Fire ProtectionFire resistance of steel structures is often provided by a coatingproduced by a spray-on cementitious process. Nano-cement (made of nanosizedparticles) has the potential to create a tough, durable, high temperaturecoatings. This is achieved by the mixing of carbon nanotubes with thecementious material to fabricate fibre composites that can inherit some of theoutstanding properties of the nanotubes.Nanotechnologies for Structural MonitoringNano- and microelectrical mechanical systems (MEMS) sensors havebeen developed and used in construction to monitor and/or control theenvironment condition and the materials/structure performance. Nanosensorranges from 109 to 105 m. These sensors could be embedded into the structureduring the construction process and could monitor internal stresses, cracks andother physical forces in the structures during the structures life (Lee et al.,2010).

Solar panel innovations

Nanotechnology could also greatlyimprove the efficiencyof solar panels, making it possible to embed a single panel with a huge array of individual solar cells. This would greatly reduce the cost of the technology, finally making solar energy a viable alternative to fossil fuel. Other explorations in making solar energy cheaper includedye-sensitized solar cells(DSSCs) and DuPont'ssilicon inkcomponent.

In addition to insulating, Aerogel also has the unique property of being translucent, potentially redefining the "glass house." Photo ofHemsworth Managed Offices(Atkins Architects)viaKalwallbyDavid Jewel.2.3Aerogel insulationWhether it's climate change or simply daunting energy bills, nearly everyone is demanding more efficient, greener new buildings. Insulation is therefore a hot topic, especially when it comes to aerogelnot only one of the lightest materials available, but also one of the highest insulators. (It also held 13 other Guinness World Records in 2011.) Originally developed by NASA, a commercial spinoff has recently emerged in the form ofThermablock, specifically designed for residential and commercial uses.