PhD offer: Control of porosity variation in concrete pavements under the influence of evaporative water flow

19 Mar 2024
Job Information

Organisation/Company

Ecole Centrale de Nantes

Department

Civil and Mechanical Engineering

Research Field

Engineering » Civil engineering

Researcher Profile

First Stage Researcher (R1)

Country

France

Application Deadline

16 Apr 2024 - 23:59 (Europe/Paris)

Type of Contract

Temporary

Job Status

Full-time

Offer Starting Date

1 Oct 2024

Is the job funded through the EU Research Framework Programme?

Not funded by an EU programme

Is the Job related to staff position within a Research Infrastructure?

No

Offer Description

When we talk about urban environments, we imply the development of housing and infrastructure and therefore an increase in soil waterproofing. This concerns, among other things, a change in the pace of biodiversity (filtration of groundwater), the associated risk of flooding, or drought. The city, while renovating itself to reduce the negative impacts on its biodiversity, must be able to continue to develop housing. It must also adapt to environmental changes.

Urban developments are responsible for the formation of “urban heat islands” (UHI). The confined nature of the dense urban environment (urban canyons) can be detrimental in summer. Indeed, radiative trapping (multiple reflections and solar absorption) and aeraulic confinement of urban canyons (recirculation zones) can cause UHIs locally. Global warming will accentuate urban canyons when the temperature difference between areas of the city becomes very large. The greening of building envelopes contributes to the direct cooling of this immediate environment. It has already been shown that planting trees along streets can reduce the shade provided and can modify the albedo of the ground and therefore UHI phenomena. However, their alignment limits street ventilation and recent studies have shown that tree photosynthesis coupled with atmospheric pollution generates poor ambient air quality. The solution for cooling streets on building facades remains the most relevant solution.

We speak of evapotranspiration the combination of the actions of evaporation of water from the soil with the transpiration of plants. The project aims to reproduce this combination with the ground-road couple. For this, the doctoral project proposes to evaluate the evaporation of water circulating under the pavements which should allow this cooling. However, periods of extreme heat are often accompanied by drought and the lack of rainwater therefore does not make it possible to supply the water circuit hoped for for cooling. A continuous water resource solution will first be proposed in the project while respecting the water cycle. Mastering water storage and evaporative flow requires a very good understanding of the phenomena in porous media. Evaporation in a porous medium is a complex phenomenon where water vapor diffusion, liquid water flow and phase change occur simultaneously. The evaporation rate depends on both the atmospheric demand (humidity, temperature and velocity of the ambient air), the porous medium and the transport properties (thermal and hydraulic conductivities, vapor diffusion). The development of an experimental protocol based on this physics is necessary to identify the type of porous materials capable of supporting an evaporative flow in summer.

The control of evaporation by the elastic deformation of pores seems to be the most relevant idea to study. In parallel with the experimental study, the development of a predictive model will be necessary by explicitly taking into account the pores in a representative elementary volume with scaling laws to model the material at the macroscopic scale. For this, a thermo-poro-elastic problem with a pressure relationship taking into account dynamic and fluid-fluid effects will be solved. Tests on concrete pavement samples will be carried out to measure the relationship between swelling and shrinkage deformations with drying and water absorption.

The PhD will be realised in the research team « Approaches for Green Engineering » (UTR INGVER) at the Institute of Civil and Mechanical Engineering. The project takes part of new research topics of the Chair EDYCEM.

Supervising:

- Frédéric Grondin (main supervisor), Full Professor, More details ;

- Ahmed Loukili (supervisor), Full Professor, More details ;

Requirements

Research Field

Engineering » Civil engineering

Education Level

Master Degree or equivalent

Skills/Qualifications

Scientific curiosity, knowledges in physics measurement methods, knowledges in modeling by finite element method, able to work in a French or English speaking environment

Languages

ENGLISH

Level

Good

Languages

FRENCH

Research Field

Engineering » Civil engineeringEngineering » Mechanical engineering

Additional Information
Benefits

Gross salary : 2100 € / month (net salary around 1750 €) with a regular increase each year. Possibility to teach with additional salary

Selection process

Candidates will be selected by the supervisors for an interview in front of a jury in May.
The selected candidates will present their profile and their skills in accordance with the PhD subject.
The jury will propose a rank of the candidates at the end of May and the candidates will receive the notification.

Additional comments

Candidates have to download their CV, motivation letter and academic marks in the website link given below.

Documents sent by email will not be considered.

 

Work Location(s)

Number of offers available

1

Company/Institute

Ecole Centrale de Nantes

Country

France

City

Nantes

Geofield

Where to apply

Website

https://theses.doctorat-bretagneloire.fr/sis/campagne-2024/controle-de-la-varia…

Contact

City

Nantes

Website

https://www.ec-nantes.fr/

Street

1 Rue de la Noë

Postal Code

44300

E-Mail

[email protected]

STATUS: EXPIRED