The Carinus Bridge is located at km 140.49 on Trunk Road 77/1 (R27) and crosses the Berg River estuary immediately south of Velddrif in the Western Cape, South Africa. Bridge inspections conducted principally by visual means, identified certain elements of the bridge that had deteriorated and has resulted in the bridge being classified as a highly critical structure. The most prominent defects relate to the half-joints in the central span (span 6) that has a drop-in element and is the longest span over the main river channel. Highways England’s CS 466 Risk Management and Structural Assessment of Concrete Half-joint Deck Structures was used to assess the primary risk. From this assessment, the half-joints on three corners were deemed a very high risk with the northwest corner being classified as immediate risk. This paper presents the findings from diagnostic tests performed at the existing bridge, with emphasis placed on the assessment of the exposure environment and reporting of environmental rate parameters that can be used for new reinforced concrete construction in the vicinity of the Berg River Estuary.