Durable and Environmental design of Monitored COncrete structures in Marine environment – DEMCOM

Durable and Environmental design of Monitored COncrete structures in Marine environment

This interdisciplinary project deals with Durability, Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) of Reinforced Concrete (RC) structures under marine environment like bridges, floating turbines... The objective is to develop an eco design method to maximize service life and minimize environmental impacts and costs of structures submitted to chloride ingress. These stakes require monitoring results to be directly integrated in durability models to improve the service life prognostic.

Development of an eco design method to maximize service life and minimize environmental impacts and costs of monitored RC structures submitted to chloride ingress.

The aim of the DEMCOM project is to tackle all these challenges through the major issue that affects marine concrete structures integrity: alteration by chloride ingress. For this purpose, this project will be divided in four Tasks (T). The methodological approach, described by the figure, is the conducting line of the DEMCOM project. Task 1 is dedicated to the management of the project. The main objective of Task 2 (T2) is to drive an experimental campaign with slag blended concrete slabs instrumented with the recently developed resistivity sensor designed for monitoring resistivity profiles over the whole thickness of a concrete structure. It is intended to address new scientific challenges: i) measuring and analyzing the electrical, conductive and capacitive phenomena, in order to extract not just one but two complementary observables, resistivity and chargeability, and their distribution in the material with a single probe ii) it would be possible to evaluate the kinetics of water and chloride penetration for concrete slabs exposed to tidal iii) analysing these outpouts data to get the input of the transport model integrating the processes of chloride and liquid transport. Task 3 (T3) is the main part of the project. It has to combine durability modeling and multi-scale modeling by validating modeled results with experimental results obtained in T2 by monitoring. T3 is dedicated to develop a multi-scale model to estimate the concrete transport properties (input of the durability model) from the concrete compounds (technological parameters), as required for combination with LCA and LCC models. Indeed one challenge of the project is that the durability and LCA/LCC models should use the same inputs which are technological parameters and environmental parameters. This will be developed in the case of other binders than Portland cement as slag. The key ingredients are respectively: 1) an appropriate hydration model to determine the amount of each phase, 2) a morphological model to describe their geometrical organisation and repartition across different length scales and 3) a suitable homogenization schemes to successively upscale the macroscopic properties of interest from those of each phase at the microscopic scales Task 4 will be devoted to the combination of durability LCA and LCC models for identifying the most favorable material solution. To optimize the design also by reducing the calculation time of the method, Sensitivity Analysis (SA) will be developed to identify the action levers for maximize service life and minimize environmental impacts and costs. Different scenario will be studied for giving recommendations dedicated to the designers to also accept environmental LCA combined with LCP analysis as decision-making tool. Advice includes optimum concrete mix design to meet specific surrounding conditions, corrosion protection for reinforcing steel by considering LCC LCA LCP analysis.