CemCover

Un nou si inovativ sistem pentru producerea tuburilor din beton si caminelor rezistente la acid.

Rezistenta la acid este obtinuta in urma unui proces patentat prin care un produs compozit constand din polimeri rezistenti si particule de sticla este aplicat pe o suprafata din beton.

Cea mai mica fractie de particule din sticla este de dimensiuni nano si deci capabila sa penetreze micii pori de pe suprafata betonului.

Astfel suprafata devine rezistenta la acid dar si la abraziune.

Aplicarea practica a CemCover

Procesul presupune aplicarea a doua straturi de material :

• - CemSeal – produs cu inalta vascozitate cu particule de sticla de marime intre 50 nm si 20 my- etanseaza suprafata betonului;
• - CemCoat – Produs cu vascozitate mai scazuta decat a CemSeal – si cu o cantitate mai mare de sticla - reactioneaza cu primul strat si se transforma in invelis protector.

The smallest fraction of the glass particles are of nano size and thereby also able to penetrate the small pores in the concrete surface.

This way the concrete surface becomes acid resistant and will not be degraded by the presence of e.g. the sulphuric acid in sewage pipes.

Furthermore, a CemCover coated concrete surface has superior abrasive strength properties which secures that the coating stays intact in the sewage system and the acid resistance of the pipes thereby remains permanent.

Practical application of CemCover

The CemCover proces involves coating of the concrete surface with two layers of coating material. The first layer - called CemSeal - fills and seals the poures within the concrete surface and the second layer - called CemCoat – completes the coating of the entire concrete surface by reacting with the first layer.

Both products - CemSeal and CemCoat - are a composite product consisting of a resistant polymer and glass particles. They have following charateristics

• CemSeal - High viscosity product with glas particles in the size range 50 nm to 20 my,
• CemCoat - Product with lower viscosity than CemSeal - and with a larger amount of glass particles.

The CemCover coating is applied to the surface of the cured concrete pipe (age at least 18 maturity hours) in three steps:

• Step one is spraying the pipe with CemSeal on a spraying carrousel.
• Step two is placing the pipe in an autoclave (pressure vessel) with 3 bars pressure for app. 15 seconds. This way the CemSeal penetrates the pores of the concrete surface.
• Step three is spraying with CemCoat on the same or another carrousel.

After a brief hardening - where CemCoat joins with CemSeal – the coated pipes can be transported to the stock yard. After 4-7 days the CemCover has reached its intended properties.

The two layers are due to the hardening process ultimately acting as one single layer.

Documentation from HawkeyePedershaab

Tests - made on full-scale concrete pipes - are to be carried out during Autumn/Winter of 2011.

These tests will provide following documentation of the mechanical and chemical properties of the coated pipes:

1. Mechanical properties
1. Abrasion tests: EN 295-3
2. Jetting resistance: CEN/TR 14920 – Jetting resistance of drain and sewer pipes
2. Chemical properties
1. Corrosion tests: Test guide line from IFF Weimar e.V.
3. Strength properties of coating
1. Adhesion test ISO 4624 – Paints and varnishes – Pull-off test for adhesion

Comparative tests with CemCover coated pipes, normal concrete pipes and clay pipes will be done and documented.

The acquiring of any national approval or accepteance of CemCover pipes remains the responsibility of the concrete pipe producer - but HawkeyePedershaab will of course assist in providing all the relevant documentation for the coating material, the coating process and the mechanical and chemical properties of the CemCover pipes as described above.