Nano-sand particles will help in constructing stronger buildings in a shorter time

Syed Akbar
Hyderabad:  Indian scientists have developed nano-sand
particles that will help in constructing stronger buildings in a
shorter time. The nano-sand particles greatly increase the strength of
cement concrete and reduce the time for curing.

A team of researchers from the Central Building Research Institute
successfully utilised nanotechnology to modify the structure of sand
to obtain nano-sand or silica particles for use in cement concrete. Dr
LP Singh led the research team.

“Addition of nano-particles of sand (silica) significantly improves
the engineering properties of the cementitious materials,” points out
Dr Singh. “Nanotechnology is finding exciting applications in the
construction sector, especially for creating innovative materials.
Nanotechnology can be used to modify the structure of materials to
improve their bulk properties such as mechanical performance, volume
stability, durability and sustainability,” he adds.

The CBRI team synthesized spherical particles of nano silica using a
substance called tetra-ethoxysilane as starting material and ammonia
as the base catalyst. The particle size of nano silica can also be
controlled.

When these nanoparticles are added in cement paste, they give
compressive strength and calcium leaching resistance to cement.

“At early stages of hydration, plain cement paste has 4.4 per cent of
calcium hydroxide while nano sand incorporated paste has only 0.5 per
cent. Addition of nano silica significantly consumes the calcium
hydroxide produced during the hydration process. Therefore, it
increases compressive strength of cement at early ages, thereby
enhancing the durability and mechanical properties of the cement
concrete,” he said.

Study of the microstructure of cement paste following the addition of
nano sand revealed that the formation of hydration products was
denser. It also becomes significantly different, giving cement
concrete additional strength and durability.