1 MECHANICS PROPERTIES OF NANO-SILICA MATERIAL CONCRETE Saloma 1 , Amrinsyah Nasution 2 , Iswandi Imran 3 and Mikrajuddin Abdullah 4 1 Lecturer, Faculty of Civil Engineering, Sriwijaya University. 2, 3 Professor of Civil Engineering, Faculty of Civil Engineering & Enviromental, ) 4 Professor of Physic, Faculty of Sciences and Mathemathics, Bandung Institute of Technology (ITB) ABSTRACT Nano-scale silica or nanosilica is a material at level of individual atoms and molecules in the range of 0.1 to 100 nanometer (10 -6 mm). Adding nano-scale silica fume into concrete mixes improves durability of concrete structures. Understanding enactment that takes place in the cement particle at a nano-scale level can lead to improved industry standard for mixing and curing concrete. Material of nanotechnology product as part of concrete ingredient enables self-consolidating concrete (SCC) of which the concrete may achieve consolidation without the need for vibration and to saving up 50% labor costs. The construction sector can benefit from this new construction material with ultra-high strength, ductility, and high durability, such as steel, polymers, and concrete. The research showed that 2.5% - 10% prosentage weight nanosilica to cement’s as partial cement substitution increases the mechanics and physics properties of concrete. INTRODUCTION The widespread use of high performance concrete in construction has encouraged more research to be conducted in this field. Some advantages of this high performance concrete makes it the most preferred for the material of the construction work. However, despite all these advantages, a problem to be solved in the high-performance concrete is how to strengthen the inter-surface zone between mortar and aggregate. Some additives commonly used to improve interface zone are silica fume, fly ash and slag. One of the new innovations in the development of material technology is nanosilica. This innovative product is processed based on nanotechnology - a technology that is capable to performing at the accuracy less than 1 m or 1 x 10 -9 m. Nanoparticles have a greater value of ratio between a surface area and a volume compared to similar particles with larger size. This makes the nanoparticles more reactive. It is expected that the composition of a given material at a certain volume will be ultra-densed, namely a packing density. Such extreme densities are due to the relatively large empty spaces between the particles, such as amongs cement particles are filled with grains of fine sands of nanometer size, either it is reactive or not. Additional material called nanosilica is used in the study. The presence of nanosilica in concrete is intended to accommodate the byproduct of the production of cement hydration in the form of free calcium hydroxide. This is made possible due to the presence of active silica oxide contained in nanosilica. There are several previous studies related to the use of nanomaterials on the performance of concrete. Nazari, A., (2010) and Luciano (2009) have conducted research on the workability and setting time of nanomaterial concrete. Furthermore, Ozyildirim, et al (2010) and Nittaya, et al (2008) examined the effect of adding nanosilica on the density of concrete. Meanwhile, Valquiria S., et al (2011), Zhang, M., (2011), M. Nili, et al (2010) and Abbas, R., (2009) conducted a study on the effects of the use of nanosilica on compressive strength of concrete. Then, a review of the effect of nanomaterials on the microstructure of concrete has also been done by Nazari, A., (2011), Khanzadi, et al (2010), Nittaya, T., and Apinon, N., (2008).