SPECIAL CONCRETE TECHNOLOGY

Question 1

Describe briefly the method “vacuum-treatment” of concrete.

Answer 1

Water is removed from the poured concrete with help of vaccum. It used for floors, especially in industries
Disadvantage:
- Complicated method- expensive

Question 2

Which effects will the vacuum-treatment have on the concrete?

Answer 2

The concrete is compacted and the vct is lowered near the surface (o,30-0-35).

Question 3

Name some advantages with vacuum-treatment.

Answer 3

• strongly reduced shrinkage
• Higher strength in the surface
• Better durability in surface
• Better abrasive resistance in the surface
• reduced initial moisture

Question 4

Describe briefly the method “fibre-reinforced concrete”.

Answer 4

Small fibres are mixed into the fresh concrete in order to replace ordinary reinfrocement.

Question 5

Name some areas of use for “fibre-reinforced concrete”.

Answer 5

• Shot-crete in tunnels
• Thin pre cast elements
• Repair of concrete
• Topping concrete on floors - especially for floors in industries

Question 6

Describe briefly the method “shot-crete”.

Answer 6

Concrete or mortar is sprayed against a surface with the help of compressed air.

Question 7

Name some areas of use for “shot-crete”.

Answer 7

• Construction of thin-walled shells
• Application of surfaces on concrete in connection with renovations
• Strenghtening of beams etc
• Repair-work, e.g. In connection with damages due to fire
• Tunnels

Question 8

Describe briefly the method “slip-form construction of concrete”

Answer 8

A vertical concrete- struccture is produced with the help of a relatively low form. The form is lifted continuously in connection with slip-form and intermittently in connection with climbing form. The pace is adjusted to the reinforcement-work, the casting of the concrete and the hardening of concrete

Question 9

Name some areas of use for “slip-form construction of concrete”.

Answer 9

• Silos
• Chimneys
• Stairs-enclosures
• Reservoirs for fluids