Transparent concrete

Dr. Andras Bela Olah

The concrete as it is known in present days

Gravel and cement and water…

The concrete as it is known by constructors I.

Portland cement (with many kind of consistence improvers) and water and aggregate…

The concrete as it is known by constructors II.

Ferroconcrete: Portland cement (with many kind of consistence improvers) and water and aggregate…. moreover some iron rods are put into it.

The concrete, which is not even called concrete

Gabion wall: unequivocally ferroconcrete without portland cement and water, but there are the iron rods and aggregate.

The concrete in realBack to the definitions:The concrete is a composite material, which consists of aggregate (gravel) and binder (cement+water).Glass concrete: the aggregate is glass fiber.Cement: CaSiO3 ; Cement+water: Ca(HSiO3)2+CaOIn practice: there was simply found a new chemical reaction, which is a little bit different than that of lime setting.Nevertheless:The meaning of cement is more (a matrix material).The meaning of composite is also more.The mixture of two materials, the aggregate and the binder (matrix).

Asphalt concrete

Asphalt: a concrete with bituminous binder.The aggregate is also stone, but the binder is more elastic.

Polimer concrete

Polimer concrete: the binder (matrix) is resin, the aggregate is gravel in this case too.

Stabilized gravel pavement

A special kind of polimer concrete. The binder (resin) is absolutely transparent, there is only one special grain size.

TransparencyFor creating transparent concrete, both the binder and the aggregate must be transparent.On the previous slide there is a good example for transparent binder, these are polimers like different types of resin, poliethylene, polipropylene, PET, policarbonate, teflon etc.To be able to find the ideal transparent aggregate there must be take into consideration its demanded attributes:High pressure resistance and great hardness. The aggregates are typically hard, with high density, very high pressure resistance and because of these they are typically brittle and fragile in greater size.

The ideal aggregate

Glass. Transparent, hard, but brittle and fragile.

Improved glasses

Layered glass, there are transparent polimer adhesive between them. This improves mechanical attributes, but in case of any damage there are still not any possibility for repair, the problem remained, only the mechanical attributes were improved.

The glass as aggregate

The glass is an amorphous silicate, ideal aggregate for composite materials. In case of it is not coloured, then the high rate of transparency can be also provided.

The binder (matrix)

The transparent polimer, which is extremely cheap and affordable everywhere: PET (poliethylene-terephthalate). The raw material of ordinary plastic bottles. It has a very good transparency, unless it is coloured.

The transparent concrete I.

A composite material made of PET binder and glass screening aggregate.Advantages- The binder is cheap and affordable (it is a waste).- The aggregate is cheap and affordable (it is a waste).- The binder can be transformed at a relatively low

temperature (200 °C)- The binder and the aggregate is weatherproof, wear-proof,

chemically neutral and repellent.- There is neither oxidation, nor ageing.- It is fireproof due to the great glass content.

The transparent concrete II.

Further advantages (mechanical properties):- Considering hardness(pressure resistance) and abrasion

resistence this new composite matrial is similar to the aggregate (glass).

- Considering the tensile strength and elasticity this new composite material is similar to the binder (the polimer).

- In case of any damage this composite material can be easily repaired, despite any similar materials (ie. security glasses). Locally heating up the material at about 200 °C and adding any necessary material surplus, the original material quality (and even the aesthetic value) can be entirely reconstructed.

The transparent concrete III.Further advantages:- The binder and the aggregate can be easily reused or even

reclaimed (reused by melting and reclaimed by simply screening after melting)

- The usage of these raw materials are environment friendly, because great amount of waste can be effectively used up on this way.

- The production is relatively cheap and has a low energy demand as against other materials (metals/metallurgy). Only mechanical processes and 200 °C is necessary.

- There is an extremely wide range of applications!!! (buildings, transparent panels, cars, trains, planes any kind of vehicles etc.)

Thank you for your attention!

D. Oláh András Béla