Nano Silica Self Compacting Concrete

Sakshi Gupta, Assistant Professor, Department of Civil Engineering, ASET, Amity University, Gurgaon, Haryana.

Introduction

Concrete, unique in construction, is the only material exclusive to the construction business and therefore is the beneficiary of a fair proportion of the research and development money from government and industry. Concrete is a composite construction material composed primarily of aggregate, cement, and water, which is a nano-structured, complex, and multi-phase material that age and gain strength over time. It is one of the most important elements for any kind of construction work.

SCC (self compacting concrete) is an important and significant advancement within concrete technology which is having a major impact on concrete practices. As one of the great innovations in concrete technology, self-compacting concrete (SCC) is in the process of casting without imposing additional vibrating forces, and only gravity is necessary to completely fill the mould cavity to form a uniform dense concrete. Compared with traditional vibrated concrete, SCC has obvious advantages in terms of reducing construction costs and improving the construction environment, with significant steps in the direction of sustainably developed concrete. The concept of Self-compacting concrete was firstly presented in 1986 by Okamura, a scholar from the University of Tokyo. He pointed out that the reduction of Japanese skilled workers has a negative impact on the durability of the concrete structures, and proposed developing self-compacting concrete which can avoid the impact on construction quality. Self - compacting concrete is a kind of concrete which is characterized by high - workability. Soon after, Ozawa, a scholar from the University of Tokyo, carried out the study on self-compacting concrete, and produced self - compacting concrete successfully in 1988 [1-3].

Thus, SCC is widely recognized as a high-performance concrete which introduces benefits in workability, durability, reduction in labour cost and higher strength properties compared to normally vibrated concrete. It involves not only high deformability but also resistance to segregation between coarse aggregate and mortar when concrete flow through confined zone of reinforcing bars. Filling ability, passing ability and segregation resistance are the fundamental fresh properties for SCC. It can be used for in situ applications as well as for precast production. SCC, has different proportions as compared to conventional concrete in a way that SCC has more quality of fine aggregates as compared to coarse aggregates and super plasticizer can be used to enhance the workability. To check the workability various tests are performed such as slump flow, V funnel, U box, L box, and J ring. The EFNARC [4] provides the need for workability which should be satisfied to fall under the category of SCC.

NBM&CW August 2016