Available online www.ejaet.com European Journal of Advances in Engineering and Technology, 2015, 2(8): 44-48 Research Article ISSN: 2394 - 658X 44 A Comparative Assessment of Nano-SiO 2 & Nano-TiO 2 Insertion in Concrete Mainak Ghosal and Arun Kr Chakraborty Department of Civil Engineering, Indian Institute of Engineering Science & Technology, Shibpur, Howrah, India mainakghosal2010@gmail.com _____________________________________________________________________________________________ ABSTRACT One of the concrete that is becoming famous for its usage nowadays is nanoconcrete and our paper deals with the fact that nanomaterials (like nano-SiO 2 & nano-TiO 2 ) when added in optimized proportions to a standard M-40 Grade concrete improves its both fresh and hardened properties (both short term & long term).The results simply corroborated the fact that for nano concrete the workability increased by more than 90% w.r.to controlled M-40 Grade concrete. The compressive strength of nano concrete with nano-SiO 2 gave a strength gain of more than 24% at 28 days and more than 18% at 90 days while that of & nano-TiO 2 gave a strength gain of more than 9% at 28 days and more than 6% at 90 days all under ordinary curing conditions. However, under exposure to MgSO 4 & MgCl 2 the standard concrete specimens gave a greater crushing strength when compared with both the nanoconcretes, the reason of which is not clear. Key words: Nanotechnology, Dwarf, Titanium Oxide, Silicon Oxide, Concrete _____________________________________________________________________________________ INTRODUCTION In the recent years nanotechnology is gaining day by day popularity in the field of civil engineering & construction technology. The objects produced using nanotechnology have unique characteristics such as super connectivity, high strength, low friction, high thermal insulation, specific beam frequency selectivity, quantum effects, extreme water repellence & self-assembling geometric patterns. In fact it was Nanotechnology that allowed creation of iPods, iPhones and all sort of these ‘i’ products which in a way completely changed the IT and electronics sectors. The continuous research in the area of concrete material & innovations has been made to cope with challenges of many construction aspects. One of the concrete that is becoming famous for its usage nowadays is nanoconcrete and it is due to its physical characteristics which makes it an obvious choice as an excellent medium of construction. Use of Nano concrete brings down weight, improves strength, allows for rationalization of design and being environment-friendly thus reducing carbon footprint is gaining attention from more academic institutes and housing construction agencies [1]. ‘Nano’ is a Greek word and means ‘Dwarf’. The new ISO working definition says that Nano technology (NT) is the application of scientific knowledge to the control and use of matter at the nanoscale (10 -9 m), where size related phenomenon & processes may occur. There have been many successful nanotechnology based applications which could have been almost impossible without utility of nano sized particles. For example, anti-scratch paints, anti- bacterial paints, anti-fouling concrete, dirt repellant textiles, clothes that need no ironing, non-reflective glasses, wonder drugs etc. are only the tip of the ice-berg. The Nanoparticles size which is below One billionth of a meter is produced as nano-additives are from traditional cement, silica (quartzite sand) or even fly ash. For larger scale, nano-Silica(nS)[the first nanomaterial to be used in construction] are produced from vaporization of silica or by feeding worms with rice husk or by precipitation method while techniques have been developed to produce Nanotubes in sizeable quantities, including arc discharge, laser ablation, high-pressure carbon monoxide disproportionate, and deposition. Nano-Titanium Oxide a Nano-additive as cement replacement in very insignificant dosages changes the hydration kinetics of entire cementitious system resulting in the improvement in the compressive strength of paste, mortar and concrete apart from its self-cleansing properties and is the most widely used Nano material today. Nano-Titanium Oxide is readily mined in its purest form from beach sand. Schomberg, a German Scientist, discovered in 1909 traces of monazite in the sand flakes on the imported coir from Sankaramangalam, Kerala, India.The beaches of