Germany - Concrete renovation on several buildings within the Westfalen barracks

Description

Project start: expected 1.3.2025
Project end: expected 1.4.2025

2. general description

When repairing concrete, it is crucial to prevent further carbonation of the concrete and thus corrosion of the reinforcing steel in the carbonated area. This should preserve the building fabric

and prevent consequential damage. The identical buildings show similar damage patterns. The damage is located in basement staircases and their roofs.

3. scope of work

3.1 Removal of loosened and cracked concrete / rust removal Remove the loose concrete over the corroded reinforcement using an electric hammer or flame blasting device. If the flame blasting device is not used, the reinforcement bars must be sandblasted to a bright metallic finish.

3.2 Corrosion protection coating

The exposed reinforcing steel is coated twice with an anti-corrosion coating. Epoxy resins, such as epoxy resin nails or polymer-modified cement slurries, are suitable for this purpose. The final coat

should be sprinkled with quartz sand to ensure a good bond with the repair mortar.

3.3 Bonding bridge

A bonding bridge is applied to the pre-wetted old concrete to improve the bond between the concrete substrate and the repair mortar. Cement-bound

bonding bridges are used. Epoxy resin, 2-component, pigmented 1-2 kg/m2 with very high bond strength should be used for this.

3.4 Repairing damaged areas

The concrete damage is repaired with hydraulically setting, polymer-modified mortar or, in the case of minor damage, with epoxy resin mortar. Plastic fibers should be added to the mortar. This should improve the cohesion and

and thus the stability of the fresh mortar. This also reduces the risk of cracking at the point of excavation. The mortar is applied to the pre-wetted, matt-moist substrate with a trowel in approx.

2 to 5 mm layer thickness. If necessary, the repair area must be shuttered. Layer thickness per application min/max: 10 mm/50 mm ;
Consumption: 2 kg/m2 and mm layer thickness

Remarks: plastic-modified, carbonation-blocking, can be applied under dynamic loads

3.5 Surface
A thin plaster coating of fine-grained, plastic-modified cement filler is used to even out structural differences and visually harmonize the repaired concrete surface.

Layer thickness per application min/max: 1 mm/5 mm

Consumption: 1.3 kg/m2 and mm layer thickness

Remarks: Can be painted over with silicate and emulsion paints

3.6 Hydrophobization

If there is a risk of cracking and a simultaneous risk of heavy moisture penetration, hydrophobization is recommended.

3.7 Surface protection

A siloxane acrylic resin-based coating is suitable for surface protection. Weather and alkali-resistant plastic dispersions provide additional protection against frost and de-icing salt. After concrete refurbishment of the

roofs, which frequently come into contact with moisture due to weathering, a protective coating is necessary to prevent damage. The protective coating should be opaque and based on synthetic resin.

be applied.
3.8 The following standards must be observed during the work:
Standard Status Title

DIN 488 1999-04 Reinforcing steel, types, properties, characteristics

DIN 1045 2001-07 Load-bearing structures made of concrete, reinforced concrete and prestressed concrete

DIN 1084 Monitoring (quality control) in concrete and reinforced concrete construction

DIN 1048 1991-06 Test methods for concrete

DIN 1164 2004-08 Cement with special properties

DIN 1504 2008-04 Products and systems for the protection and repair of concrete structures

DIN 4030 2006-10 Assessment of water, soils and gases attacking concrete

DIN 4226 2002-02 Aggregates for concrete and mortar

3.9 Additional requirements: Building 3/1 and Building 103

The stairs on the above-mentioned buildings that lead to the building must be sealed at the building connection.

be sealed at the building connection.
4. materials and equipment

All materials and equipment are to be provided by the contractor and must comply with the applicable standards and regulations.

comply.

Opportunity closing date

13 February 2025

Value of contract

to be confirmed