MATETPRO - Matériaux et Procédés pour Produits Performants

Optimization of functional properties of particulate aerated materials – ProMAP

Foamed particulate materials

Optimized functional properties for foamed particulate materials

Stakes and Objectives

This project deals with issues related to Foamed Particulate Materials (FPM), encountered as foams produced from granular suspensions, such as cement or plaster pastes for example. Those materials have a high development potential in the context of thermal renovation of buildings. However, their thermal performance is currently insufficient in most cases and a dedicated research work has to be made.<br />The most ambitious objective is to understand the link between the microstructure of those foamed materials, which partly results from the incorporated particles, and the functional properties, i.e. mechanical, thermal and acoustical properties. As a second major objective, we would like to understand and to control the mechanisms responsible for the deterioration of the structure during the early age of the fresh material, i.e. before the hardening.

A significant part of our work is based on model (simplified) systems, consisting in well-controlled arrangements of bubbles and particles. The great advantage of such approach is to allow for a precise parametric study of fluid and solid FPM, which has not been possible in previous studies. More precisely, it is now possible to quantify the effect of particle size on the morphology and the functional properties of FPM.
The time evolution of the morphology in the fluid systems, i.e. between the generation stage and the hardening, is deeply studied. This allows for the dynamics of segregation phenomena to be understood and modelled. At solid state, we characterized the resulting morphology as a function several control parameters: particle size, bubble size, particle content, binder (or liquid in case of fluid systems) and gas contents. We measure the mechanical, thermal and acoustical properties of the model systems, and for each property, we look for the presence of an optimum. This general approach allows for relevant strategies to emerge for elaborating multifunctional materials.
The project is based also on a dedicated theoretical work in order to interpret the experimental results and to develop numerical tools for optimizing all the functional properties mentioned above. Those understanding elements will help to develop a rational way for elaborating FPM of industrial interest, such as cement foams.

- A new generation method has been developed for elaborating several foamed materials with well-controlled bubble size and gas volume fraction, allowing for a complete parametric study to be performed.
- Highlighting of a morphological transition controlled by a geometrical parameter, ?, that compares the particle size to the one of interstices between particles.
- This morphological transition is found to be responsible for the transition observed for several properties of the foamed materials, such as drainage (gravity induced segregation) and rheology of fluid systems, or the mechanics of solid systems. We expect other properties to be also concerned by this transition.
- The theoretical work showed that a normalized transition can be obtained for each investigated property, and that all the normalized data can be described with the same (unique) curve as a function of the parameter ?.

- In the following we will focus on the transition observed for drainage, rheology and mechanical properties. We will evaluate if it is possible to describe all the properties of foamed particulate materials using our theoretical framework.
- We will investigate more complex systems where functional particles are used. Particles of interest will we PCM (phase-change-material) particles, where latent heat capacity can provide interesting thermal properties to be exploited in combination with foam properties.
- We will continue the effort devoted to the development of numerical tools for the simulation of foam samples and the modeling of the functional properties of foamed particulate materials.
-We will pursue our work on systems having a direct industrial interest, such as cement foams. The objective is to identify the sets of parameters controlling the morphology during the early age of the material (several hours for cement).

[ACL 1] Critical size effect of particles reinforcing foamed composite materials, Composites Science and Technology (2015) 119, 62-67
[ACL 2] The drainage of foamy granular suspensions, Journal of colloid and interface science (2015) 458, 200-208
[ACL 3] Linear elastic properties derivation from microstructures representative of transport parameters, The Journal of the Acoustical Society of America (2014) 135, 3172
[ACL 4] Foam clogging, Soft Matter (2014) 10, 6990-6998
[ACL 5] Capture-induced transition in foamy suspensions, Soft Matter (2014) 10, 4137-4141
Flow and jamming of granular suspensions in foams, Soft Matter (2014) 10, 3277-3283
[Conf 1] «Flow and jamming of granular suspensions in foams«, Eufoam 2014, 7-10 juillet, Thessalonique
[Conf 2] «The clogging of aqueous foams«, Eufoam 2014, 7-10 juillet, Thessalonique
[Conf 3] «Strengthening of soft polymer foams loaded with rigid inclusions«, Eufoam 2014, 7-10 juillet, Thessalonique
[Conf 4] «Rheology of emulsion foams«, 10th European Rheology Conference, 14-17 avril 2015, Nantes,
[Conf 5] «Flow and jamming of granular suspensions in foams«, 10th European Rheology Conference, 14-17 avril 2015, Nantes
[Conf 6] «Flow and jamming of granular suspensions in foams«, Journées de la Matière Condensée 2014, 24-29 aout, Paris
[Conf 7] «Mousses particulaires«, Matériaux 2014, Montpellier
[Conf 8] «Strengthening of foamed composite materials«, Congrès Français de Mécanique, Lyon, 2015
[Conf 9] «Rheological behaviour of foamy complex fluids «, Eufoam 2016, 3-6 juillet, Dublin
[Conf 10] «Model cement foams «, Eufoam 2016, 3-6 juillet, Dublin
[Conf 11] «Rheological behaviour of foamy complex fluids«, ICR 2016, 8-13 août, Kyoto

New constraints on energy consumption impose a strong research effort in order to develop new materials, less energy-consuming during their production, energy-saving during their use, and more efficient in recycling processes. The incorporation of air into conventional materials appears to be a simple and efficient answer to these new constraints, in every stage of the material life, from the production stage to its use as thermal insulation material in buildings. This proposal concerns issues for aerated materials known as Particulate Aerated Materials (PAM), elaborated from granular pastes, such as cementitious and plaster pastes. The potential of development of these MAP is huge, especially in the field of the thermal renovation of buildings, because contrary to the nowadays used organic foams, these materials are incombustible and can be directly produced on construction site. Nevertheless, in order to increase their thermal performance at a level comparable to that of organic foams, important research effort must be undertaken in order to increase as much as possible the fraction of incorporated air, and so increase the energy benefits which we have just recalled. So, from slightly aerated materials, they are called to become foamy materials. This transition is under way in building materials companies, but it is nowadays hindered by several major scientific challenges that must be overcome to develop this class of new materials in an optimum way.

This proposal aims at overcoming a decisive stage in the understanding and the development of the existing PAM. We like to elaborate model systems for which it is possible to control finely all parameters influencing their properties. These systems will allow us to study in a parametric manner the properties of solidified and non-solidified PAM. The most ambitious objective is to develop one or several functions of industrial interest (thermal, acoustical) without degrading the mechanical resistance of the material. The morphological evolution of these systems between the instant of their generation and their hardening, which poses serious difficulties in their elaboration nowadays, will be also studied to resolve the numerous issues encountered for this class of materials.

This multidisciplinary proposal gathers academic and industrial partners with supplementary competences, covering all theoretical and experimental aspects in physics and chemical physics of cellular materials, in mechanics, in heat science and in acoustics. Dedicated work will be simultaneously devoted to model systems, allowing for a complete experimental study to be undertaken on problems of industrial interest, as well as a rigorous comparison of results obtained with theoretical predictions – also developed as part of this proposal. The optimization of industrial materials, such as foamed concrete, is also planned.

Project coordination

Olivier PITOIS (Laboratoire NAVIER)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

NAVIER Laboratoire NAVIER
MSC Laboratoire Matière et Systèmes Complexes
MSME Laboratoire de Modélisation et Simulation Multi Echelle
SGR SAINT GOBAIN RECHERCHE

Help of the ANR 448,812 euros
Beginning and duration of the scientific project: December 2013 - 42 Months

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