International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 03 Issue: 05 | May-2016 www.irjet.net p-ISSN: 2395-0072 © 2016, IRJET | Impact Factor value: 4.45 | ISO 9001:2008 Certified Journal | Page 401 STUDY OF HIGH STRENGTH TERTIARY BRAND CONCRETE WITH VARYING CONTENTS OF MICRO SILICA Pendhari Ankush R. 1 , Karnawat Nivedita S. 2 , More Sayali A. 3 , Nandakumar Gopalkrishnan. 4 , Patil Sneha M. 5 1 Assistant Professor, Dept. of Civil Engineering, GESCOE, Nasik. 2, 3, 4, 5 Final Year Students, Dept. of Civil Engineering, GESCOE, Nasik. ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Concrete is the most important engineering material in construction industry because of its inherent strength properties. However, the addition of some other materials may change the properties of concrete. With increase in trend towards the wider use of concrete for pre- stressed concrete and high rise buildings there is a growing demand of concrete with higher compressive strength. Micro- silica, also called as silica fumes is produced in electric arc furnace as a by-product of the production of elemental silicon’s or alloys containing silicon. The mineral admixtures with pozzolanic properties such as fly ash (FA), silica fume (SF), ground blast-furnace slag (GGBS) and metakaolin (MK) are commonly used as a partial substitution of Portland cement during construction. These admixtures are often added to modify the physical and chemical properties of cementitious mixes, performances and engineering properties of the concrete. In comparison to ordinary Portland cement, the collection of GGBS as a by-product requires less energy and it produces less greenhouse gases. Thus, GGBS blended concrete is a more environmentally friendly concrete compared to OPC concrete. This paper presents the study of variation of contents of micro silica in the mix consisting of cement, GGBFS (ground granulated blast furnace slag), and micro silica. Micro silica is used in three percentages 0%, 7%, and 10% and the compressive strength test of cubes is being conducted. Key Words: compressive strength, cementitious content, GGBFS, Micro silica, pozzolanic. 1. INTRODUCTION Fly ash, ground granulated blast-furnace slag, silica fume, and natural pozzolans, such as calcined shale, calcined clay or metakaolin, are materials that when used in conjunction with Portland or blended cement, contribute to the properties of the hardened concrete through hydraulic or pozzolanic activity or both. Supplementary cementitious materials are added to concrete as part of the total cementitious system. They may be used in addition to or as a partial replacement of Portland cement or blended cement in concrete, depending on the properties of the materials and the desired effect on concrete. Traditionally, fly ash, slag, calcined clay, calcined shale, and silica fume were used in concrete individually. Today, due to improved access to these materials, concrete producers can combine two or more of these materials to optimize concrete properties. Mixtures using three cementitious materials, called ternary mixtures, are becoming more prominent. 2. MATERIAL Ground granulated blast furnace slag (GGBS) is a by-product from the blast-furnaces used to make iron. These operate at a temperature of about 1,500 degrees centigrade and are fed with a carefully controlled mixture of iron-ore, coke and limestone. The iron ore is reduced to iron and the remaining materials form a slag that floats on top of the iron. This slag is periodically tapped off as a molten liquid and if it is to be used for the manufacture of GGBS it has to be rapidly quenched in large volumes of water. The quenching optimises the cementitious properties and produces granules similar to coarse sand. This 'granulated' slag is then dried and ground to a fine powder. Silica fume, also known as microsilica, is an amorphous (non-crystalline) polymorph of silicon dioxide, silica. It is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy production and consists of spherical particles with an average particle diameter of 150 nm. The main field of application is as pozzolanic material for high performance concrete. Silica fume is an ultrafine material with spherical particles less than ͳ μm in diameter, the average being about Ͳ.ͳͷ μm. Cement, type of cement is important mainly through its influence on the rate of development of compressive strength of concrete. The choice of the type of cement depends upon the requirements of performance at hand. The most commonly used cement is ordinary Portland cement. Variation in the cement quality will cause the compressive strength to vary more than any other single material. 2.1 Tests on material The materials required and determining their various properties has been carried out in this phase. The Constituents of concrete viz. cement, fine aggregate, and