Ifsttar PhD subject

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Title : Chemical admixture in model suspensions: a multi-scale study

Main host Laboratory - Referent Advisor Navier  -  GOYON-TROHAY Julie      tél. : +33 181668480

Director of the main host Laboratory SULEM Jean  -

PhD Speciality physico-chimie des matériaux

Axis of the performance contract 2 - COP2017 - More efficient and resilient infrastructure

Main location Marne-la-Vallée

Doctoral affiliation UNIVERSITE PARIS-EST

PhD school

Planned PhD supervisor CHATEAU Xavier  -  Université Gustave Eiffel  -  Navier

Planned PhD co-supervisor GOYON-TROHAY Julie  -  Université Gustave Eiffel  -  Navier

Planned financing Contrat doctoral  - Ifsttar

Abstract

In this experimental PhD thesis, we investigated the effects of a surfactant admixture in colloidal suspensions made of silica beads. The rheology of these materials (yield stress, shear elastic
modulus, aging) arises from adhesive contacts between the silica beads. These contacts are formed by adding a calciumchloride salt into the suspensions.We probed the suspensions frommacro to micro scale using rheometry, zetametry, Total Organic Carbon, confocal microscopy and optical tweezers experiments. Results highlighted that the surfactant leads to non-monotonic variations in the suspension bulk rheology. These variations arises frommicrostructure and contact changes when the surfactant adsorbs onto the silica particle surfaces.We compared these fundamental results on silica bead suspensions, which are model materials, to the behaviour of crushed quartz suspensions in order to assess the scenarios we proposed
from the standpoint of industrial applications.

Keywords : suspensions, colloidal interactions, rheology, chemical admixtures, contact, microstructure

Main host Laboratory - Referent Advisor	Navier - GOYON-TROHAY Julie tél. : +33 181668480
Director of the main host Laboratory	SULEM Jean -
PhD Speciality	physico-chimie des matériaux
Axis of the performance contract	2 - COP2017 - More efficient and resilient infrastructure
Main location	Marne-la-Vallée
Doctoral affiliation	UNIVERSITE PARIS-EST
PhD school
Planned PhD supervisor	CHATEAU Xavier - Université Gustave Eiffel - Navier
Planned PhD co-supervisor	GOYON-TROHAY Julie - Université Gustave Eiffel - Navier
Planned financing	Contrat doctoral - Ifsttar
Abstract In this experimental PhD thesis, we investigated the effects of a surfactant admixture in colloidal suspensions made of silica beads. The rheology of these materials (yield stress, shear elastic modulus, aging) arises from adhesive contacts between the silica beads. These contacts are formed by adding a calciumchloride salt into the suspensions.We probed the suspensions frommacro to micro scale using rheometry, zetametry, Total Organic Carbon, confocal microscopy and optical tweezers experiments. Results highlighted that the surfactant leads to non-monotonic variations in the suspension bulk rheology. These variations arises frommicrostructure and contact changes when the surfactant adsorbs onto the silica particle surfaces.We compared these fundamental results on silica bead suspensions, which are model materials, to the behaviour of crushed quartz suspensions in order to assess the scenarios we proposed from the standpoint of industrial applications.
Keywords :	suspensions, colloidal interactions, rheology, chemical admixtures, contact, microstructure

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