UNIVERSITÉ PARIS-EST ÉCOLE DOCTORALE Sciences, Ingénierie et Environnement Thèse de doctorat Spécialité : géotechnique Chi-Wei CHEN A MINERALOGICAL APPROACH TO USE THE NON-QUALIFIED FINE AGGREGATES IN ASPHALT CONCRETE PAVEMENT Thèse dirigée par Jean-Pierre MAGNAN Soutenue le 29 Mars 2016 Jury : Rapporteurs : George E. CHRISTIDIS Technical University of Crete Véronique SCHMITT Université de Bordeaux Examinateurs : Anne PANTET Université du Havre Jean-Eric POIRIER Colas Groupe Directeur de thèse : Jean-Pierre MAGNAN IFSTTAR Co-Directeur de thèse : Yannick DESCANTES IFSTTAR Co-encadrant de thèse : Myriam DUC IFSTTAR Vincent GAUDEFROY IFSTTAR © 2016 Chi-Wei CHEN ALL RIGHTS RESERVED To my grandmother, every word was crafted while missing you. I know you are sitting on a rainbow and being pround of me. Preface and acknowledgments My curiosity started growing by encountering the construction problem in pile foundation while I was working as a geotechnical Engineer 8 years ago. My engineering background was unable to explain the occurrence of construction damage, but I knew there was a better solution than pouring more and more concrete into the foundation: it is finding the solution by seeing problem through scientific and engineering aspects. Therefore, I left my engineer position and started the journey of completing my Geo-scientific knowledge. Time was too fast to rewind the life after it – warming up for living abroad through working holiday at Australia, learning Geomaterials and Geosciences through International Master of Advanced Clay Science (IMACS), seeing the world through traveling and living in foreign countries, and being tough through finding my own strength. There was nothing easy, but these experiences fertilized me to have hands-on competence for completing the PhD in Geotechnical engineering. The work of my master thesis collaborated between IMACS and IFSTTAR enlightened me to solve Engineering problem by applying Geo-scientific and Geotechnical engineering skills. My beloved supervisor, M. Duc, recruited me for PhD and showed me the beauty of seeing through the problems and the excitement of bottoming up the solutions. I have not only learnt to be a passionate scientist from her, but also saw the most grateful heart during these years, which fills with trust, sympathy and supporting. By seeing the valuable personalities of my dear co-director, Y. Descantes, I have also learnt to be helpful, to be self-required and to be realistic for my work. I have also seen the patience, compassion and kindness whenever I asked advices to my adorable director, J.-P. Magnan, Moreover, I have learnt to be efficient, to be rational and to be cheerful from my delightful co-supervisor, V. Gaudefroy. I appreciate all of them that brought me on their shoulders to see further during these 3.5 years. Certainly, working with them was the best gift in my PhD life. Moreover, this PhD work was credited to E. Hamard, A. L'alloret, O. Burban, J. Demoncheaux, D. Demare, O. Garcin, F. Hammoum, T. Gabet, B. Bechet, A. Cothenet, J.-P. Terrier, F. Buisson, S. Buisson and N. Buisson from IFSTTAR as well. Their generosity and help made the success of this study and my fantastic stay at Nantes. Luckily, I have met my international family, M. Harikiopoulo, J-P.Harikiopoulo, A. Guimond-Barrett, L. Radtke, S. Miñarro, J. Yousaf, S. kleinz, A. Maloula, A., Potysz, A. Ganzenko, F. Dudouyt, K. Pluta, L. Lefort, A. Themeli, E. Gennesseaux, F. Maillet and my softball teammates, BK Paris, supported me and listened to me all over these years. I appreciate their protection and warming me up when I lost the faith and missed the direction in life. Last, to my original Family in Taiwan, thank you for these unconditional loves even with my 8 years absence, the honor of this PhD title belongs to you. To who is interested in my work, wish you a pleasant reading journey in my PhD dissertation. Chi-Wei CHEN Marne-la-Vallée, March 29, 2016. 1 2 Abstract The need to save natural aggregate resources in a sustainable development approach led to consider quarry sands of bad quality. The presence of clays in the fine fraction of these sands has been known for long to increase the water sensitivity of hot-mixed asphalt (HMA), with the risk of mitigating the lifetime of asphalt concrete pavements. In order to detect the presence of clay fines and quantify their harmfulness, methylene blue (MB) tests are routinely performed on sands used for HMA mix design. As the relation between the MB value of a fine aggregate and the Duriez value assessing the water sensitivity of a HMA mixture is questionable, MB tests may by mistake disqualify some sands. The present research investigates the clay mineralogy of various sands to better predict the water sensitivity of a HMA mixture. Water sensitivity seems to be caused by cohesive failure in kaolinite- HMA mixtures, whereas swelling properties of clays are responsible for the stripping of HMA incorporating illite or montmorillonite. As a consequence, HMA mixtures comprising kaolinite have a higher water resistance than HMA mixtures comprising illite or montmorillonite. Furthermore, the high valence of compensating cations onto clay surface coupled to small cation radius (eg. Ca2+ and La3+) may improve the water resistance of illite- and montmorillonite- HMA mixtures. Upon observing the correlations between Duriez test, MB value or CEC value and clay mineralogy, a new methodology for sand qualification was suggested and validated successfully on several natural fine aggregates. This methodology is comprised of four steps: when the conventional MBdrop test (step 1) used to qualify fine aggregates in France is in excess of MB2 threshold, cation exchange capacity (CEC or MBCEC) (step 2) measurements are performed which generally extend the range for fine aggregates qualification. Would the fine aggregate remain non-qualified, clay mineralogy is identified and quantified using XRD powder pattern and Reitveld method, as far as possible validated by a complementary method using chemical analysis. The clay mineralogy is then used to calculate the Duriez value that has to be compared to the 0.8 threshold (step 3) whereas the experimental Duriez test (step 4) is performed when the conclusions from step 3 are unclear. Key words: clay, mineralogy, asphalt concrete pavement, hot mix asphalt, stripping, methylene blue value, qualification, Duriez test, surface energy. 3 4 Résumé La nécessité d’économiser les ressources naturelles en granulats dans une logique de développement durable conduit à s’intéresser à certains sables stériles de carrière. La présence d’argiles dans la fraction fine de ces sables est connue pour accroître la sensibilité à l’eau des enrobés hydrocarbonés à chaud (EHC), avec le risque de raccourcir la durée de vie des chaussées. Afin de détecter la présence de telles fines et de quantifier leur nocivité, des essais de bleu de méthylène (MB) sont usuellement réalisés sur les sables entrant dans la confection des EHC. Cependant, la relation entre la valeur MB d’un sable et la valeur de Duriez caractérisant la sensibilité à l'eau d'un EHC n’étant pas explicite, cette pratique est susceptible de disqualifier à tort certains sables. La présente recherche examine la minéralogie des argiles de différents sables afin de mieux prédire la sensibilité à l’eau d’un EHC. Celle-ci semble se traduire par une rupture cohésive de la phase liant à l’interface eau-bitume-argile dans un EHC contenant de la kaolinite, alors que les propriétés de gonflement des argiles de type illite et montmorillonite sont responsables du désenrobage dans les EHC correspondants. Par conséquent, un EHC contenant de la kaolinite est moins sensible à l’eau qu’un EHC contenant de la montmorillonite ou de l’illite. De surcroît, la valence élevée des cations compensateurs à la surface de l'argile ainsi que leurs petits rayons (par exemple Ca2+ et La3+) peuvent améliorer la résistance à l'eau d’un EHC contenant de l’illite ou de la montmorillonite. A partir de l'observation des corrélations entre l’essai Duriez, la valeur de bleu ou la capacité d’échange cationique et la minéralogie de leurs argiles, une nouvelle méthodologie de qualification des sables pour EHC est proposée et a été validée avec succès sur quelques sables naturels. Quatre étapes composent cette méthodologie: lorsque la valeur de bleu MBdrop classique (étape 1) utilisée pour qualifier des sables en France est supérieure au seuil MB2 habituel, la mesure de la capacité d'échange cationique (CEC ou MBCEC) (étape 2) permet d'élargir la gamme des sables qualifiables. Faute de qualification, les argiles sont ensuite identifiées et quantifiées en soumettant le sable à une analyse par diffraction de rayons X sur poudre avec exploitation du diffractogramme par la méthode Reitveld, si possible suivie d’une validation par une méthode ‘complémentaire’ utilisant l'analyse chimique. La minéralogie de l'argile est alors utilisée pour estimer la valeur de Duriez qui doit être comparée au seuil de 0,8 (étape 3), tandis que la mesure de la valeur de Duriez (étape 4) est réalisée lorsque les conclusions de l'étape 3 ne sont pas claires. Mots-clés: argile, minéralogie, mélanges bitumineux pour couche de chaussées, bitume à chaud, désenrobage, bleu de méthylène, qualification, test Duriez, énergie de surface. 5 6 TABLE OF CONTENT PREFACE AND ACKNOWLEDGMENTS ....................................................................................... 1 ABSTRACT ..........................................................................................................................................