| PROJECTS |
State-of-the-art
CONCRETE REPAIR
C ut t i n g- e d g e S pr ay l o c k C o n c r e t e P r o t e c t i o n’s S C P t e c h n o l o g y w a s deployed in the successful repair of five concrete silos at Rio Tinto’s Richards Bay Minerals (RBM) operation, SA’s largest minerals sands producer. SCP 743 was specif ied as part of the repair design by LNW Consulting Engineers, a leading provider of multidisciplinar y eng ineering and project m a n a gement ser v ices to t he heav y industrial engineering and commercial sectors. On t he company’s prev ious projects, SCP 743 enhanced concrete remediation practices. It fills the concrete capillaries and pores to waterproof the construction material. Tests have shown that concrete treated with SCP 743 can withstand 100m of negative head pressure. Depending on the mix designs, SCP 743 purges and/or encapsulates contaminants within the concrete capillary and pore structure, eliminating their contribution to reinforced concrete distress. Enhanced concrete remediation LNW Consulting Engineers also supervised the repairs, which were undertaken by Rodcol Contracts, a concrete repair specialist
with a solid track record providing quality services to all industries in the Zululand area, Swaziland, the Natal Midlands, Mozambique and the Eastern Cape. Walter Muhl, CEO of Rodcol Contracts, says a total of 4 725m 2 of concrete was treated with SCP. “SCP is an extremely effective product, in terms of its ability to purge concrete of contaminants and provide permanent protection. While initially costlier than other available products on the market, it significantly reduces the maintenance of reinforced concrete structures, saving time and money over the long term,” he says. Rodcol Contracts mobilised to site at the end of 2019. The repairs to the five structures, including Char Silo 1 and 2, Ore Silo 4, Magnetite Silo and Lime Silo, were successfully completed at the end of 2020.
Monstrous and time-consuming Considering the sheer size of the silos, it was an extensive undertaking. Ore Silo 4 is 20m in diameter and 34m high; the Char Silos are 12m in diameter and 25m high, and the Lime and Magnetite Silos are each 7m in diameter and 17m high. The most onerous and time-consuming
“The most onerous and time-consuming process entailed first erecting scaffolding inside and outside the structures to provide access to the work areas.” process entailed first erecting scaffolding inside and outside the structures to provide access to the work areas, the largest of which was Ore Silo 4, where SCP was applied over 2 095m2. The external repairs f irst entailed removing the spalled and cracked concrete and then cleaning and treating the exposed reinforcing bar with an epoxy coating. SCP 743 was then applied to the opened concrete area to neutralise the concrete and bring it back to an acceptable level. Once the repair was completed, SCP 743 was applied to the repaired concrete and the surrounding areas. A Sika repair system and protective coating was then applied to complete the repairs. (Top): SCP 743 was specified for the repair of five concrete silos at Rio Tinto’s Richards Bay Minerals Operation by LNW Consulting Engineers.
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PRECAST | ISSUE ONE | 2022
