A Brief Guide To The Working Of Silica Fumes For Concrete
Silica Fumes are very important when it comes to concrete and construction purposes. Furthermore, there are various other uses of silica fumes. But, silica-fumes for concrete is one of the most distinct and precise purposes of using the particular material.
This particular piece of writing highlights the precise uses of silica fumes in the construction industry and what are the changes that take place in a concrete mix after the addition of silica fumes. Read on to know more.
When silica-fumes are added to the concrete mix, it remains as an inert material. Silica fumes for the concrete mix are extremely important when it is added to the mixture of Portland cement and water. But, before knowing what the uses of this particular material are, you need to know what is the change that takes place when silica-fumes is added to the concrete mix.
Also, you need to know what changes occur during the reaction of silica fumes with water and cement. Follow the subsequent section to know what happens when silica fumes are added to the concrete.
What Happens When Silica Fumes For Concrete Is Added To The Mix?
When you add silica-fumes for the concrete mix to the concrete itself, it remains inert. Once the water and Portland cement in the mixture start reacting with each other (or the hydration of cement starts), the basic chemical reactions give rise to two chemical compounds namely - CSH and Ca(OH)2.
The compound names Calcium Silicate Hydrate or CSH is mainly responsible for the crystallization part of Silica Fumes for concrete. Furthermore, the Calcium hydroxide which is also known as the free lime is mainly responsible for lining the available pores of the concrete. It basically works as a filler compound and helpful in leaching out weak concrete.
A pozzolanic reaction takes places among the silica fumes which, in turn, produce Calcium Silicate Hydrate in the voids present around the hydrated cement particles. This additional Calcium Silicate hydrate not only produces a strong and flexible bond among the concrete particles, but also the matrix tends to be a lot stronger by the increase in bond-strength.
Uses Of Silica-Fumes For The Concrete Mix
When silica-fumes are added to the concrete mix, it reduces permeability and increases the electrical resistance power of the concrete mix. These benefits are mainly witnessed when is fresh. In the hardened state, one might not be able to notice the changes in the concrete mix.
The particle size of the concrete becomes greatly finer when silica fumes are added to its mix. It produces a ball-bearing effect because the fineness modulus of the concrete improves to a great extent. It helps in creating a thixotropic behavior which, in turn, modifies the viscosity of the concrete.
Silica fume particles have a high surface area. That is the reason why it affects segregation, mobility of water in the concrete, and helps in reducing the bleeding property of the concrete.
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