Industrial Concrete Silo Restoration and Strengthening

Project description

Location: Milos Island
Year: 2018

The 10 reinforced concrete silos of 10m diameter and 30m height are part of the industrial facilities of IMERYS SA (former S&B) at Voudia, Milos Island, and were gradually constructed from 1970 to 1990. Due to the highly corrosive environment, reinforcement corrosion and concrete degradation were present. ENKA carried out the restoration and strengthening of the oldest silos.

Tasks description

In 2018 ENKA executed the restoration and strengthening of silo No2 and of the top beam ring of silo No10.

The works that took place were the following: scaffolding installation at the full height of the silos, removal of the loose concrete, sandblasting and cleaning of the corroded reinforcement, application of corrosion inhibitor onto the reinforcement, installation of new steel reinforcement and dowels, and construction of 15cm thick jacket with shotcrete, with its pour in-situ foundation.

At the beginning of the 2000’s, repairs of the silos comprising corrosion inhibitors, repair mortars, and coatings that protect against carbonation took place, but 15 years later new and more extensive damages appeared. Thus, Xypex Concentrate was applied at the whole surface of the shotcrete jacketing of silo No2 to permanently waterproof and seal it and, so, protect it from any kind of water ingress. That way, the steel reinforcement was protected against corrosion and the life expectancy of the structure was largely prolonged.

In general, the chloride concentration inside the existing concrete was below the max acceptable limits.

The process followed and the materials and systems used were in accordance with relevant standards (mainly EN 1504) and the Greek Technical Guidelines (ΕΤΕΠ).