Concrete protective liner protects against acid
Project name: Rehabilitation of tanks AGRU Oberflächentechnik GmbH
Project date: 2009 – 2011
Products: PP-R concrete protection, 8mm
Prefabricated basin
Already in 2009 AGRU Kunststofftechnik GmbH delivered concrete protective liners which were used for the rehabilitation of tanks in a facility for anodic treatment of aluminium in Grünburg (Austria). Due to the success further tanks followed in 2010 and 2011.
Initial situation
For the surface treatment during the anodisation of aluminium basins with different chemicals are used. In particular sulphuric acid, chromic acid as well as detergents and rinsing agents are applied.
The existing tanks were satisfactorily used for more than 30 years. For corrosion protection they were lined with standard PP sheets on the inside surface. Over the years the concrete showed significant corrosion due to the continuous contact with vapour from sulphuric acid. Consequently the load bearing capacity was reduced. Furthermore the leak tightness could not be ensured in the long run. Hence, the decision was made to renovate the basins.
The pilot project
The planning started in May 2008. It was soon evident that the biggest challenge for this project would be the timeline. To ensure occupational health and safety it was not possible to conduct the renovation during production. As a result all the work on-site had to be scheduled for the shut down during winter holidays. Altogether only 3 weeks in December 2008 and January 2009 were available.
Due to the excellent operating experience using polypropylene over a period of 30 years, PP was chosen for the renovation. In particular concrete protective liners made from PP-R were used. In order to reduce the risk of accidental damage and also to have enough safety in case of abrasion, sheets with a thickness of 8 mm were selected. Furthermore all attached and built-in parts were fabricated from PP-R sheets and pipes.
The only possibility to meet the stringent timeline was to prefabricate the entire basin and the built-in parts. The fully welded basin made from concrete protective liners was delivered to the facility. It was lifted into the existing concrete tank by a crane. There it was aligned, applied to an inner formwork and cast into concrete.
Follow-up projects
Due to the successful renovation of the first tank and the excellent experience with SureGrip concrete protective liners follow-up projects were made. Altogether 6 additional tanks were renovated from 2009 until 2011. A close cooperation between the companies Heson and AGRU was the key for the effective completion of these projects.
