Corrosion of lined concrete

Author(s): M.Valix, A.W. Cheung, R. C. Sendanayaka and M.K. Nazemi
Paper category: Proceedings
Book title: Proceedings of the Final Conference of RILEM 253-MCI Microorganisms-Cementitious Materials Interactions Volume I
Editor(s): Alexandra Bertron and Henk Jonkers
ISBN: 978-2-35158-207-7 (Set)
ISBN: 978-2-35158-209-1 (Volume1)
e-ISBN: 978-2-35158-206-0
Publisher: RILEM Publications SARL
Publication year: 2018
Pages: 183-192
Total Pages: 288
Language : English

Abstract: This study examined the corrosion of concrete pipes lined with commercially available PVC coating. The lined pipes have been in service for 9-34 years in Water Corporation sewers exposed to average environmental conditions comprising of 6-391 ppm H2S, temperatures of 25-30C and relative humidity of 86 to 97%. Sampling of the coated concrete was conducted at the crown, wall and tidal zones of the pipes. The extent of corrosion was assessed from the surface pH, acid neutralisation capacity, and alkalinity of the extracted concrete. The mineralogical changes were examined by thermal gravimetric analysis and by scanning electron microscopy and elemental mapping. Our results showed the high surface pH and alkalinity of the concrete that has been protected by the PVC coating reflected resistance to corrosion. The lined concretes appear to have corroded primarily by carbonation. While the transformation of H2S, in the absence of sulphur oxidising microorganisms, to intermediate elemental sulphur within the concrete, appears to have restricted the corrosion. It appears the H2S inhibition of sulphur reducing microorganism contributed to the inverse effect of H2S concentration on the corrosion of the lined concrete. These results demonstrated the importance of the performance of PVC coating as a barrier and the environmental conditions in retarding the corrosion of lined concrete pipes.

Online publication : 2018
Publication type : full_text
Public price (Euros) : 0.00

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