Graduation date: 2004

Graduation date: 1995

Institute of Paper Science and Technology / Thesis (Ph. D) -- Institute of Paper Science and Technology, 1998.

published_or_final_version / abstract / toc / Dentistry / Master / Master of Philosophy

No description available.

No description available.

No description available.

Thesis (Ph. D.)--Columbia University, 1936. / Vita. Bibliography: p. 39.

The work in this thesis examines the suitability of utilising ground waste brick as a cement replacement material. The brick types investigated were obtained from the UK,Denmark, Lithuania and Poland. Cement was partially replaced by various quantities and types of ground brick in mortar and concrete. Compressive strength, pore size distribution and sorptivity of mortar generally all benefit from the presence of ground brick and the greatest effect can be seen after water curing for one year. Compressive strength of concrete is also shown to increase as the fineness of ground brick increases although the optimum particle size for ground brick in concrete is still to be determined. The ground bricks investigated have a significant effect on the performance of ground brick mortar when exposed to sodium sulphate solution and synthetic seawater. It is seen that depending on the chemical and phase composition, the effect of ground brick can increase substantially the rate of deterioration of mortar or can reduce significantly the expansion observed. No definite mechanism was identified as being responsible for the observed deterioration of mortar exposed to sodium sulphate solution although it seems likely that water intake due to ettringite formation and adsorption of water by the resultant colloidal product are the primary causes of expansion. Sulphate content, glass content and oxide chemistry of brick are key factors as to its performance when used as a cement replacement material in mortar. Bricks with a high proportion of low calcium glass make very effective pozzolans. Bricks with high calcium glass or a low proportion of glass should not be used as pozzolans. Small amounts of sulphate in ground brick do not have any serious deleterious effects on ground brick mortars and can be beneficial. It is established that it is technically feasible to partially replace cement with ground brick in mortar and concrete, depending on its chemical and phase composition to produce a more durable, cost effective and (due to the lower cement content) a less environmentally damaging material than that produced without cement replacement.

La société LTF (Lyon Turin Ferroviaire), filiale de RFF (Réseau Ferré de France) et de RFI (Réseau Ferré Italien) est le promoteur de la section transfrontalière de la future liaison ferroviaire entre Lyon et Turin. LTF souhaite valoriser une grande partie des 16 millions de m3 de déblais qui seront générés par les chantiers du futur tunnel de base en granulats à béton pour le revêtement du tunnel. Cette solution est proposée dans le cadre d'une démarche de développement durable. Cependant, pour une partie des matériaux qui doivent être valorisés en granulats à béton, la teneur en sulfates est comprise entre 1,61 et 4,30% en masse (exprimé en SO3). Ces matériaux se démarquent alors par rapport au contexte réglementaire qui limite la teneur en sulfates dans les granulats à béton à 0,2% pour ce type d'ouvrage. Cette prescription est appliquée pour éviter les risques de dégradation du béton par réaction des sulfates apportés par les granulats avec certains composants présents dans le ciment. Ce phénomène est connu sous le terme de réaction sulfatique interne. Les travaux de recherche ont porté dans un premier temps sur la lixiviation des sulfates issus des matériaux d'excavation. Les résultats ont montré que les sulfates sont rapidement accessibles dans les fractions granulométriques inférieures à 4 mm. Un possible traitement des matériaux par lavage avant leur utilisation dans le béton peut être une solution pour limiter l'attaque sulfatique interne. Dans un second temps, pour définir un liant adapté à ce type de granulats, une étude comparative de différents ciments supposés résistants aux sulfates a été mise en place. Trois essais accélérés ont été développés afin de prendre en compte le risque de dégradation des matériaux cimentaires par formation d'ettringite et de thaumasite. Seuls deux ciments présentent un bon comportement vis-à-vis de la réaction sulfatique interne engendrée par des granulats contenant une forte teneur en sulfates. Il s'agit d'un ciment Portland à très faibles teneur en alcalins et ne contenant quasiment pas d'aluminates tricalciques ainsi qu'un ciment sursulfaté. Enfin, une dernière solution innovante a été proposée et réside dans l'utilisation des sulfates apportés par les matériaux d'excavation pour réaliser le gypsage du ciment. Les sulfates provenant du sable excavé permettent de réguler correctement la prise du matériau cimentaire au même titre que les sulfates de calcium ajoutés au clinker dans le ciment / The construction of a 57 km length base tunnel for the future railway link between Lyon (France) and Turin (Italy) promoted by Lyon Turin Ferroviaire (LTF), subsidiary of Réseau Ferré de France (RFF) and Rete Ferroviaria Italiana (RFI), will result in the production of 16 millions of m3 of excavated materials. In order to promote efficient and sustainable management of natural resources and to reduce greenhouse gas emission and environmental impact, one wish of LTF is to use the most part of these materials as concrete aggregates. However, a part of the excavated materials from LTF tunnel has a sulphate content between 1.46 and 4.30% (expressed in mass of SO3) and cannot be used considering the European standards, which drastically limit the sulphate content in order to avoid structural damages resulting from internal sulphate attack. The sulphate content is limited to 0.2% for this type of construction. The first study, carried out in order to define solutions for the use of these excavated materials, focuses on the behaviour of sulphates, more particularly on their leaching in solution in order to determine the sulphate content that could be released in the concrete. The results show that the sulphates are quickly available for the particles size lower than 4 mm. The washing of excavated materials before their use in concrete can be a solution to limit the internal sulphate attack. The second study has been conducted in order to define a suitable cement for the use of excavated materiels as aggregates. A comparative study of different cements supposed to be resistant to sulphates has been carried out. Three accelerated tests have been developed to assess the risk of degradation of cementitious materials by formation of ettringite and thaumasite. Only two cements show a good behavior against the internal sulphate attack resulting from sulphated aggregates. These cements are a Portland cement with a very low calcium aluminates and alkaline contents and an over sulphated cement.In the frame of a third study, an innovative solution has been proposed and concerns the using of excavated materials as a source of sulphates for regulating the hydration of cement. Sulfates from the excavated sand can regulate the cement hydration and then cancel any further damage due to sulphates