Catherine Noiriel recommends Alexandru Popa for a PhD program. During his 6-month internship, Alexandru assisted PhD student Gaël Blanc by conducting experiments on efflorescence formation in cementitious materials using various techniques, including 3D imaging with X-ray microtomography. Alexandru demonstrated great intellectual ability in understanding the scientific aspects and adapted easily to new techniques. Catherine found Alexandru to be highly motivated, polite, and open-minded. Gaël Blanc also recommends Alexandru, praising his planning skills, analysis abilities, curiosity, and ability to integrate into the laboratory team.

3. 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.

4. 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