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CONCRETE TECHNOLOGY32 CPI %u2013 Concrete Plant International %u2013 6 | 2025 www.cpi-worldwide.coma two-tiered approach that can improve durability assessment practices in industry. As such, durability control assessment can be carried out quickly, and substantiated by further testing in the laboratory in inconclusive or cases where there may be an indication of potential durability issues. This approach provides a rigorous assessment of in-situ gas permeability, and hence potential durability.Concluding remarksThe study explored opportunities for site implementation of a combined gas permeability testing approach using the OPI and Torrent method. The OPI and TPT methods had similar responses to experimental variables such as w/b ratio, binder type, and age on site-manufactured concrete elements in the summer season of Cape Town, South Africa. A strong correlation was found between the methods (R=-0.80), aligning with the observations from previous studies. A basis for practical implementation was put forward, involving a two-tiered approach enabling comprehensive site testing using non-destructive methods, and complemented by laboratory testing in scenarios of potential durability acceptance issues. Future work will analyze the influence of moisture on the site correlation of the OPI and TPT methods. nReferences[1] M. G. Alexander, J. R. Mackechnie, and Y. Ballim, %u2018Guide to the use of durability indexes for achieving durability in concrete structures%u2019. pp. 1%u201318, 1999.[2] M. J. Alexander, %u2018Durability indexes and their use in concrete engineering%u2019, pp. 9%u201322, 2005, doi: 10.1617/2912143586.002.[3] M. G. Alexander, A. Bentur, and S. Mindess, Durability of concrete: Design and construction. CRC Press - Taylor & Francis Group, 2017.[4] G. W. Nganga, %u2018Practical implemenation of the durability indexbased performance approach%u2019, MSc. Thesis submitted to University of Cape Town, 2012.[5] G. W. Nganga, M. G. 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Fig. 7: Correlation between OPI and Torrent methods for existing and current data.