Citi-Con was again entrusted with repairing concrete silos. This time, the repairs were urgent and, therefore, had to be completed in a very short period.
We delivered according to expectation by completing quality workmanship within the three-week contractual period. This significant feat was achieved by deploying our rope access expertise. It provided a cost-effective and faster method of mobilising to site and then executing the works. Our seasoned rope access technicians also performed in a safe manner while working at heights of up to 36m. All of Citi-Con’s rope access technicians have been professionally trained. They have also been certified by the Rope Access Chamber – The Institute For Work At Height to work at height. Citi-Con is also a proud member of The Institute For Work At Height.
Repairing concrete silo conical roofs
The work scope included repairing seven concrete silo conical roofs. High pressure washing was used to remove debris before thoroughly inspecting the roofs for cracks. They were repaired with a 100mm polyester membrane and sealed with a primer coat. We then applied three coats of a.b.e. Super Laycryl acrylicliquid waterproofing compound, to complete the repairs.
super laycryl® | a.b.e.® Saint-Gobain is a highly flexible liquid applied emulsion that has been reinforced with a.b.e. membrane. Refer to abe® membrane | a.b.e.® Construction Chemicals.
This system provides an in-situ, seamless professional waterproofing system. With its sound weathering properties and adhesion, it carries a conditional 10-year warranty when maintained correctly by an expert. This should ideally be done every two years to avoid extensive and costly repairs.
Our workmanship plays an important role in avoiding contamination of agricultural product stored in the silos. Silo roofs that are not maintained can also eventually collapse. Silo roof beams are a frequent area of corrosion or concrete deterioration due to roof leaks. Spalling of concrete roof beam pockets can further expose beams and lead to eventual roof failure.
Repairing concrete silo walls
The project also entailed repairing concrete spalling on the silo walls. After undertaking an extensive structural investigation and preparatory work, we treated the reinforcing bar with a.b.e. Durarep ZR primer. A single-component liquid epoxy resin, enriched with metallic zinc, this system provides excellent corrosion protection properties. durarep ZR Primer | a.b.e.® Saint-Gobain achieves longevity of repair via a electro-chemical reaction.
Thereafter, we applied a.b.e. Epidermix 344, a structural wet-to-dry concrete adhesive. Notably, epidermix 372 | a.b.e.® Saint-Gobain provides a robust, long-lasting bond with high compressive and lap shear strengths.
We then reinstated the areas with a.b.e. durarep FR – Mortar | a.b.e.® Construction Chemicals and left it to cure for three days. The polymer-modified fibre-reinforced, cement-based mortar provides high ultimate strength.
a.b.e Silocoat, a two-component polymer-modified cementitious coating, was then applied to the areas. abe® silocoat | a.b.e.® Saint-Gobain cures to form an impermeable membrane that withstands high positive and negative hydrostatic pressures. It is also an effective barrier to sulphates [Sulfates and concrete. | Concrete Society]. This is in addition chlorides [Chlorides and concrete. | Concrete Society] and low pH. The system also slows down carbon ingress [Carbonation of concrete | Concrete Society].
Systems for repairing concrete silos
Citi-Con is an approved applicator of quality systems for repairing concrete silos. This enables us to guarantee our workmanship for the maximum available term.
As an approved a.b.e.® Saint-Gobain • Innovative Construction Chemical Solutions applicator, we ensure the correct use of its systems. This includes when maintaining them during the warranty period.
Achieving a complete repair solution depends on selecting a suitable product and a contractor that is knowledgeable in its use. All too often, project specifications are limited to specific technical properties of products. Scant regard is given to specifying substrate prerequisites, correct application methods and detailing information. These are also critical to the success of a concrete repair project.
Considering the specialised work involved in repairing and maintaining silos, owners of these assets only work with the best.
They appoint contractors on their experience and track record undertaking similar work, key to warranty credibility. This is also underpinned by the experience of the contractor’s supervision/project management team.
Longevity of association between the system supplier or manufacturer and contractor are also important.