Catherine Noiriel Lecurer in Geosciences Université Paul Sabatier -UMR 5533 Géosciences Environnement Toulouse- 14, avenue Édouard Belin F-31400 Toulouse tél +33.5.61.33.30.16 catherine.noiriel@univ-tlse3.fr

Toulouse, August 2015

To whom it may concerned

Purpose : recommendation letter for Alexandru Popa

It is with great pleasure that I write this letter of recommendation for Alexandru Popa. I met him 6 months ago when he came to France for a traineeship at the Department of Civil Engineering, Institut des Sciences Appliquées, University of Toulouse. At the time, he was willing to complete his engineering degree with an experience in research. He was proposed to assist a PhD student, Gaël Blanc, by working on efflorescence formation in a new formulation of cementitious materials. The project focused on possible damage involved by salt crystallization within porous network of mortar, and was supported by the company Ménard, which is specialized in soil foundations.

During his traineeship, Alexandru had to run sulfate attacks through capillary rise on mortar plugs of different sizes and compositions, and to characterize chemical, mechanical, and geometry changes derived from the attacks using different techniques, i.e. weighing, Hg-porosity, mechanical tests and 2D and 3D imaging. He was also involved in acid attack experiments for another project with his fellow student, Glad Licsandru. Among the different techniques used, 3D imaging using X-ray micro-tomography was employed to better characterize the effects of salt crystallization on the mortars structure. Although I belong to another Department at the University, I had the opportunity to collaborate with him on the project, especially on the design of the capillary rise experiments and the imaging part. Alexandru demonstrated the great intellectual ability required to understand all the scientific aspects of the problem and adapted easily to new techniques, among other image processing of 3D data sets, which was very new for him. This fact is certainly supported by his curiosity in various domains. It has always been a pleasure to discuss very different scientific topics when we got imaging time allocated. In addition, he was eager to volunteer for work, and was always open to discussion and get pieces of advice.

In the months I have interacted with Alexandru, I found him to be very polite, open-minded, thoughtful, and highly motivated. Alexandru’s self-motivation and keen desire to learn and work hard to succeed in his projects are to be recommended. I certainly believe that he has talent and drive to achieve success in a PhD project. That is why I strongly recommend him into the institution he will apply for a grant.

Yours sincerely,

Dr Catherine Noiriel, lecturer in Geosciences, with expertise in water-mineral interactions, crystallization pressure in rock materials, and 3D imaging with X-ray micro-tomography.

Gaël BLANC

PhD student in Civil Engineering

LMDC Laboratory, 135 avenue de Rangueil

31077 Toulouse Cedex 4, France

tél +33.5.67.04.88.40

g_blanc@insa-toulouse.fr

Toulouse, September 2015

To whom it may concerned

Letter of recommendation for Alexandru Popa

From January 2015, thanks of the Erasmus Program, Alexandru Popa followed a 6 months traineeship

at the LMDC laboratory of the Civil Engineering Department, Institut des sciences Appliquées,

University of Toulouse.

His topic concerning “ the multi-scale analysis of cementitious materials subjected to chemical attack

by X-Ray micro-tomography” was a side project of my PhD subject, which is focusing on the

durability analysis of deep underground foundations.

Sulfate attack, leaching process and salt crystallization have been analyzed on different mortar

compositions using mechanical tests, chemical analyses and 2D/3D imaging using micro-tomography.

The general process of micro-tomography is simple as it takes hundreds of X-Ray scans of a sample to

build a 3D volume. Even though this technique was new to Alexandru, he rapidly understood the

machinery process and 3D software used in the laboratory (Avizo 8.1) thanks to his spirit of curiosity

and a great involvement in the topic.

Alexandru has also shown a good planning method to take care of all the experiments from the start to

the end: sample and solution preparation, regular measurements, micro-tomography analyses and 3D

rendering. He was regularly asking questions about his topic and expressed new ideas on the

experimental campaign.

Throughout the traineeship, Alexandru has shown an important interest about specific aspect of my

thesis as well as in different research domains in civil engineering, exchanging with PhD students and

technician about their work in the laboratory. Alexandru integrated in the laboratory’s team really fast

due to his open-minded spirit, easy and pleasant nature and also, curiosity.

Thanks to his fast-learning skills, his good planning methods, his analysis mind, his curiosity and his

personal human qualities, I think he has all the skills to succeed in a PhD. I strongly recommend him

to the institution he will apply for a grant.

Yours sincerely,

Gaël BLANC