NANO CONCRETE - TECHNOLOGY AT ITS BEST

NANO-CONCRETE TECHNOLGY 

Nanotechnology in the civil field has proved to make the construction faster, cheaper, safer and more varied. Automation of Nanotechnology construction can allow for the creation of structures from advanced home to skyscrapers much more quickly and efficiently. 

Amorphous nano-silica (nS) particles were incorporated in cement concrete, and their effect on the fresh state behaviour was analyzed. Nano concrete is defined as concrete made by filling the pores in traditional concrete using nanoparticles of size <500nano meters. 

Nanoparticles of silica turn into nanoparticles of cement (nano cement) in the chemical reactions that take place in the concoction of the concrete. When concrete is reduced to Nano level its properties are strongly influenced so that it increases their strength & durability. 

Addition of nano-silica to the concrete leads to improve the material passing which results in the densifying of micro & Nanostructures.  

The incorporation of ultra-fine particles into a Portland-cement paste within a concrete mixture alters the concrete's material properties and performance by reducing the void space between the cement and aggregate in the cured concrete. This improves strength, durability, shrinkage and bonding to steel reinforcing bars.

MANUFACTURING OF NANO-CONCRETE

To ensure the mixing is thorough enough to create nano concrete, the mixer must apply a total mixing power to the mixture of 30–600 watts per kilogram of the mix. This mixing must continue long enough to yield net specific energy expended upon the mix of at least 5000 joules per kilogram of the mix and may be increased to 30–80 kJ per kilogram. 

A superplasticizer is then added to the activated mixture which can later be mixed with aggregates in a conventional concrete mixer. In the HEM process, the intense mixing of cement and water with sand provides dissipation and absorption of energy by the mixture and increases shear stresses on the surface of cement particles. As a result, the temperature of the mixture increases by 20–25 degrees Celsius. 

This intense mixing serves to deepen the hydration process inside the cement particles. The nano-sized colloid Calcium Silicate Hydrate (C-S-H) formation increased several times compared with conventional mixing. Thus, ordinary concrete transforms into nano concrete. 

The initial natural process of cement hydration with formation of colloidal globules about 5 nm in diameter spreads into the entire volume of cement–water matrix as the energy expended upon the mix. 

The liquid activated high-energy mixture can be used by itself for casting small architectural details and decorative items or foamed (expanded) for lightweight concrete. HEM Nanoconcrete hardens in low and subzero temperature conditions because the liquid phase inside the nano-pores of C-S-H gel doesn't freeze at temperatures from −8 to −42 degrees Celsius. The increased volume of the gel reduces capillarity in solid and porous materials.

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