Solution: Concrete Repair & Protection
When the steel reinforcement of the concrete Balby Flyover began to suffer from corrosion due to carbonation and chloride attack, Doncaster Council needed a reliable renovation method that would provide long term protection. The solution also had to enable the bridge to remain open during repair works. It specified a concrete repair system from global building product manufacturer, Sika, for its outstanding market reputation.
Preventing the corrosion of steel reinforcement in concrete is essential. Consisting of high performance mortars, anti-corrosion agents and sealants, Sika’s proven concrete repair system – trusted to the extent that it was used on Spanish City, the world’s oldest reinforced concrete dome – ensures that any structure will be able to stand the rigours of usage for years into the future.
Sika was involved with the project from the start, having been approached directly by the Bridges Division of Doncaster Council. After meeting with the council’s engineers, Sika’s technicians analysed the problems facing the bridge and specified a solution – meeting the council’s brief for a cost effective, reliable and long lasting system. Sika was even able to recommend possible contractors for the scheme.
Repairs, which were undertaken by ROK Concrete Repairs, were required across the structure of the bridge. These included the soffit, columns, deck and abutment walls. As the bridge was a key part of Doncaster’s road infrastructure, it remained open for the duration of works. Key to Sika’s concrete repair system is that it can be quickly applied and has a life expectancy upwards of fifteen years – meaning that the disturbance of renovation is brief and need not be repeated regularly.
The smaller concrete repairs were conducted using cementitious polymer modified Sika Monotop 610/615. Monotop 610 is first applied. It inhibits corrosion, improving the lifespan of steel reinforcements. It also acts as a bonding bridge for Sika Monotop 615 high build repair and re-profiling mortar. Where more extensive concrete repairs were required, Sikacem 133 Gunite was used. The cement based, polymer modified one component repair mortar contains silica fume and a high range of water reducing agents. It can be spray applied for quick application, making it ideal for large scale projects such as the Balby Flyover.
The entire reinforced concrete sections of the bridge were then covered by a spray applied coat of Sika Ferrogard 903. A crucial part of Sika’s concrete repair system, this innovative liquid inhibits corrosion, delaying its start and slowing its rate – extending the maintenance and service life cycles of reinforced concrete for fifteen years. Easily and economically applied to surfaces, it’s a simple way to protect reinforced structures. As it does not have an adverse effect on concrete, it is frequently specified on valuable structures and heritage projects.
For a final level of concrete protection, a coat of Sikagard 680S Clearglaze was applied. A one part solvent coating, it’s resistant to weathering, alkalis and ageing. Suitable for a variety of mineral surfaces, it has a self cleaning effect and does not adversely affect the characteristic texture of concrete.
Following extensive testing, Sika’s entire range of concrete repair products is certified to BS EN 1504, the European standard for concrete repair. This accreditation applies not only to the production quality of the products themselves but also to the guidance issued with them. The accreditation ensures users of the high quality nature of Sika’s concrete repair systems.
Longstanding concrete renovation is essential for a variety of public and private structures. For its effectiveness, Sika’s concrete repair system has ensured simply applied, economical and longstanding preservation of the Balby Flyover. It stands as an example of why Sika’s innovative products are a favourite of specifiers and operatives the world over.