Browsing by Author "Melinge, Y."

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External corrosion to concrete sewers : a case study
(2012) Oualit, M.; Jauberthie, R.; Rendell, F.; Melinge, Y.; Abadlia, Mohamed Tahar
The aim of this study was to investigate the deterioration of concrete sewers and identify responsible factors; this investigation was a part of an ongoing asset evaluation for Rennes (France). The sewer studied was a 300 mm spun concrete pipe laid in 1992. Core samples (D 28 mm, L 40 mm) were taken from different areas of a pipe (invert, crown and side wall) and analysed to quantify the condition of the concrete and the extent of damage to the internal and external surface of the pipe. Physical and mechanical properties of the material were characterised. The depassivation of the concrete was measured by testing with a phenolphthalein solution. The study showed that in this particular case the external corrosion was extensive with minimal internal corrosion. It is proposed that the corrosion was possibly linked to the use of a contaminated backfill or organic acids in the ground water. Recommendations are proposed concerning the direction of future research
Performance and analysis of concrete in sewer environment : anisotropy of damage
(2011) Oualit, M.; Jauberthie, R.; Melinge, Y.; Abadlia, Mohamed Tahar
The costs associated with the provision and maintenance of drinking water and wastewater infrastructure represents a signiﬁcant ﬁnancial demand worldwide. Maintenance costs are disproportionately high, indicating a lack of adequate durability. The aim of this paper is to study the degradation mode and the responsible factors of deterioration concrete pipe, used in the sewage’s city of Rennes (France). Thus, samples taken from different areas of the pipe (Raft, medium and roof) were analyzed using investigation methods in order to illustrate the internal and external rate of damage, caused by effluents and ground. In addition, chemical and mineralogical changes recorded were identified using scanning electron micrographs (SEM). In this research program, chemical and mechanical studies were performed by measuring the compressive and splitting tensile strengths. A phenolphthalein indicator solution is applied to a concrete specimen on a fresh fracture surface to determine the corrosion of steel reinforcement and the diseases advancement (pathologies depth). This study clearly shows the important anisotropy of both, internal and external damage. Finally, recommendations are proposed in line with the environment and possible approaches to sustainability assessment are also imposed