Durability of concretes in urban sewer systems

Technologically, the cement-based sanitation network is of various constitutions and the use of more efficient materials contributes to a better durability. However, if today, it is easy to identify reference states, as to the properties of materials and structures, the highlighting of these reference states is delicate for old structures and formulations. The objective of this paper is to study the sustainability of the sewerage networks in the city of Rennes (France) made up of cement-based pipes. Data relating to the characteristics of the pipes were collected (type of network, diameter, thickness, date of installation ...) for each section studied. In addition to the apparent quality of the samples, characterization tests were carried out on core cylindrical specimens such as density, porosity and compressive strength. The results of the analyzes are discussed and correlations are established to explain the evolution of the properties of the materials and to evaluate the kinetics of alteration. This investigation is performed in order to be able to envisage the operations of maintenance in a logic of prevention and not consecutive to an accident.