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With the introduction of waste legislation, in the form of regulations and directives, in many parts of the world a significant move towards sustainable waste management is becoming a legal requirement. Emphasis is now being placed on increasing recycling and promoting more sustainable practices for waste materials, including glass. The present research, therefore, aimed at examining the feasibility of Foamed Glass Gravel (FGG) as construction material, in particular Geofil Foamed Glass Gravél (GFGG), a manufactured lightweight secondary aggregate, for use as a primary aggregate substitute in concrete production. Comparison is made at all times with other FGG material, namely Hasopor, and other lightweight by-product manufactured material namely Lytag. In the main, research was carried out in three distinct parts; Part 1 examining the key characteristics of GFGG (following relevant BS and BS EN standards), Part 2 assessing its suitability for use in concrete applications, and Part 3 providing practical implications of the findings. The programme of work was designed to establish benchmarking level for coarse and fine GFGG and to provide simple practical guidelines for its use in concrete. The research has identified some of the key practical and application issues for utilising GGFG in concrete. The physical characteristics of GFGG were found to be comparable, and in some cases superior, to those obtained for currently available manufactured lightweight secondary aggregates. The grading of GFGG was found to be almost within the limits of lightweight aggregates with similar voids ratio as that of NA. Typically, GFGG, rough in it's texture, could create better mechanical interlocking with cement paste than smooth aggregates. GFGG had 60- 65% lower bulk density, 40-50% lower apparent particle density and water absorption 3 to 5 times higher than natural Thames Valley Gravel but still performed comparable to other lightweight aggregates. However it was found to have slightly higher density than Hasopor, but also higher heat and crushing resistance. Overall, characterisation test results showed that GFGG has a potential for use as quality lightweight aggregate in concrete production. However, it was noted that the precautions may be necessary to take account of bubble densities and water absorption characteristics to guarantee suitable fresh properties of concrete. In order to determine the practical upper limit of GFGG content for a range of applications and to assess the performance of GFGG concrete, mixes were proportioned using Natural Aggregate (NA) and GFGG bubbles blends with up to 60% coarse or 15% fine bubbles- by volume. The general trends observed indicate comparable workability with inclusion of GFGG in concrete mixes and slump loss with time was not adversely affected. Results of compressive strength testing showed that up to 30% coarse or 15% fine GFGG had negligible effect on the cube and cylinder strength of concrete and using up to 15% fine GFGG caused a slight increase in cube, cylinder and other engineering properties. Moreover, within 3-days 30% coarse GFGG and (5-15%) fíne GFGG concrete mixes achieved on average 73% of 28-day compressive strength. This increased to 85% within 7 days, regardless of GFGG content when compared to NA (Control) concrete mixes. However, results show gradual reduction in strength with an increase in GFGG content beyond 30% coarse in the mix. Indeed, the results showed that such reduction in strength with high GFGG proportions can be compensated for by adjusting the mix water/cement ratio. The results also showed that the original glass source had a negligible effect on fresh and key bulk engineering properties of resulting concrete. The subject of GFGG concrete durability study included initial surface absorption, carbonation rates and alkali-silica reaction testing. In general, GFGG concrete mixes were found to posses near surface absorption properties similar to the corresponding NA concrete mixes, providing GFGG content was restricted to 30% coarse or 15% fme. Carbonation rates for up to 60% GFGG mixes were comparable to NA mixes. Results of accelerated ASR testing of 30-100% fine GFGG mortar prisms indicated that none of the tested samples expanded significantly during the test and that damaging deleterious expansion due to ASR did not occurred during testing. The practical implications of the study to the construction industry are also discussed.

This research was undertaken to investigate the effectiveness of carboxylic corrosion inhibitor in fly ash and silica fume (respectively FM and SM) samples and nitrite-based corrosion inhibitors in fly ash (FGC) sample. The findings from this research show that the addition of the carboxylic inhibitor altered the hydration of fly ash and silica fume self-compaction concretes (SCCs) by delaying the formation of ettrngite and the production of portlandite in the FM and SM samples and ultimately causing the calcium aluminate hydrates to surround the fly ash and cement particles. It was shown that this resulted in slight setting retardation in the silica fume particles but significant delay in the hydration of the fly ash SCC. Further, this development brought about by the use of the carboxylic inhibitor contributed bleeding of different levels in the fly ash and silica fume samples and this condition was shown to increase the heterogeneity of the FM and SM SCCs. Although addition of the nitrite-based inhibitor retarded the setting of paste of the fly ash SCC, no noticeable delay in the hardening of the concrete was manifested. When the nitrite-based inhibitor was included in the fly ash SCC, the physical structure of the interfacial transition zone and the bulk of the mortar were found to be less porous and hence the concrete displayed a higher level of homogeneity. The incorporation of the carboxylic inhibitor increased the corrosion resistance of the silica fume concrete to chloride -induced corrosion but the corrosion resistance of the fly ash SCC was only improved when exposed to low concentration of chloride ions. The reduction in the inhibiting capacity of the FM SCC to high chloride load was the result of the elevated degree of porosity and higher propensity to chloride migration resulting from the use of the carboxylic compound. On the other hand, when the nitrite compound was used in the fly ash SCC, the current density was reduced which is ascribed to the effectiveness of the inhibitor and the reduction in the porosity and chloride migration that resulted from the incorporation of the inorganic compound. However, as the concentration of the corrosion inhibitors increased, the corrosion resistance of the inhibited SSCs reduced. The study also shows that the nitrite fly ash see showed the ability to undergo self-healing of corroded reinforced concrete but the carboxylic inhibited types of SCCs (FM and SM) could only prevent further corrosion after the corrosive environment is removed. Comparative testing showed that, in all three types of inhibited SCCs, there is a high probability that the inhibiting capacity will become depleted under certain conditions of chloride exposure. Using the nitrite inhibitor in the fly ash SCC also imparted moderate to significant improvement to the 7 - 60-day compressive strengths but the long term strength of the concrete was slightly lower than that of the traditional fly ash SCC. When the carboxylic compound was used in the fly ash SCC, the 7 - 28-day compressive strengths were marginally lowered and the 60 - 90-day compressive strengths were profoundly reduced. The addition of the carboxylic inhibitor to the silica fume SCC also significantly reduced the 28 - 90-day compressive strengths of the concrete.

Understanding the correlation between the mix proportions, micro structural characteristics, and macro-scale properties of concrete (i.e. the process-structure-properties relationship) is fundamental to achieving a more advanced understanding of how to apply and optimise this abundant engineering material. Although, concrete has been traditionally evaluated by its physico-mechanical and functional properties; development of advanced and effective inspection techniques during the last decade has demonstrated that fundamental macro-level properties of concrete depend, to a great extent, on its properties at the micro- and nano levels. This research was intended to make a quantitative assessment of impact load-induced micro-structural damage in concrete and, more particularly, to investigate the influence of ITZ micro-and nano local properties (as influenced by aggregate characteristics) on the impact load-induced cracking behaviour of concrete. Five different types of concrete mixtures were designed with the same total water cement ratio either by using natural aggregates as reference or by totally replacing the natural coarse aggregate with unconventional aggregates (such as copper slag, blue brick, sintered fly ash and tyre rubber) having significant differences in strength, shape and surface texture, porosity and roughness, and elasticity. A range of advanced techniques including X-ray diffraction, mercury porosimetry, 3D X-ray computed tomography coupled with digital image analysis, laser surface profilometry, 3D nanotech vertical scanning interferometry and scanning electron microscopy fitted with energy-dispersive X-ray spectrometer were used to characterize the aggregates and the concrete micro-structures. Based on the results obtained a possible mechanism for the micro-structural damage in concrete was proposed. Poorer aggregate characteristics alone could be responsible for a greater ITZ deterioration after loading but the results demonstrated that in fact, the aggregate causes a change in the ITZ conditions and it is these altered ITZ conditions that have a major effect on overall mix behaviour and govern the damaging process of concrete under impact loading. It was also concluded that the presence of a weak and porous ITZ has two opposite effects on the failure process. First, the chemical and porosity heterogeneities within the ITZ can cause fluctuations/disordering in the cracking (fracture) path, resulting in an increase in the tortuosity and corresponding fracture energy dissipation. Second, a weak and porous ITZ transfers less stress from the matrix to the aggregate particles. This leads to a lower compressive strength but increased toughness due to micro crack path lengthening and energy dissipation. Finally, the effect of the aggregate on the surface area roughness of the ITZ was established for the first time in the concrete literature. The roughness number of the area near the ITZ was found to positively correlate with dissipated surface fracture energy. An increase in the roughness number is associated with an increase in the dissipated fracture energy. The significance of this correlation however, lies in the fact that the rougher near – ITZ fraction of the bulk paste is more resistant to cracking at the macro level. Findings from this study will lead to a better understanding of the impact load-induced micro-structural damage phenomena. In addition, the micro-structural data from SEM and X-ray CT obtained during impact and mechanical testing of the concrete mixtures could be used to develop a multi-scale finite element model to simulate and predict the behaviour and fracture damage of concrete subjected to dynamic loading.

Concrete, our most widely used construction material, is a fluid that offers the opportunity to economically create structures of almost any geometry. Yet this unique fluidity is seldom capitalised on, with concrete instead being cast into rigid prismatic moulds to create high material use structures with large carbon footprints. Our rate of concrete consumption means that cement manufacture alone is estimated to account for some 5% of global Carbon Dioxide emissions. This dissertation shows that by replacing conventional orthogonal moulds with a flexible system comprised primarily of high strength, low cost fabric sheets, the fluidity of concrete can be utilised to create structurally optimised concrete structures. Flexible formwork therefore has the potential to facilitate the change in design and construction philosophy that will be required for a move towards a less material intensive, more sustainable, construction industry. Optimisation and design processes developed in this thesis show that material savings of up to 40% are possible in flexibly formed concrete beams. Full scale structural testing of these processes is undertaken to verify the flexural and shear behaviours of non-prismatic elements. This is supported by further experimental and theoretical investigations into the durability of concrete cast in a permeable, flexible mould. Detailed analysis is provided alongside practical guidance for designers. Coupled with innovation in design and analysis techniques, flexible formwork is shown to provide a globally accessible method for the construction of low carbon, materially efficient and architecturally interesting concrete structures. Recognising the impact construction has on the environment, design philosophies centred around the need to put material where it is required are becoming increasingly desirable. This can now be achieved by replacing rigid formworks with systems comprised of flexible sheets of fabric. This is a step change in the way we think about our new concrete structures.

Le béton est un des matériaux de construction les plus répandus. Néanmoins son comportement en traction dynamique n’est pas parfaitement connu. C’est afin de mieux concevoir les structures en béton et de prédire leur ruine dans le cadre d’éventuels accidents industriels qu’il est nécessaire de connaître sa résistance. Cette dernière évolue en fonction des différentes sollicitations auxquelles le béton peut être soumis. Afin de caractériser la résistance en traction d’un béton de type R30A7, ainsi que son évolution en fonction de la vitesse de déformation, différents essais de flexion trois points ont été réalisés que cela soit en statique ou en dynamique. Un dispositif conforme aux normes en vigueur en statique ainsi que le dispositif dynamique des barres de Hopkinson ont été utilisés. Ce dernier permet de réaliser des essais dynamiques en mesurant le chargement et la vitesse en entrée comme en sortie. En plus de l’instrumentation traditionnelle, les essais ont été suivis à l’aide d’une caméra rapide afin de réaliser des mesures de champ de déplacement à l’aide de la corrélation d’images numériques. Des outils utilisant ces champs de déplacement ont été créés afin de suivre au mieux l’apparition et l’évolution de la fissure. L’ensemble de ces moyens de mesures permettent, avec l’aide de différentes modélisations, qui prennent en compte ou non l’endommagement des éprouvettes, de caractériser l’évolution de la contrainte de rupture en traction en fonction de la vitesse de déformation. Ce travail a mis en avant le fait qu’ignorer l’endommagement du matériau lors d’essais dynamiques augmente de manière non négligeable la valeur de la contrainte à rupture déduite des essais. / The concrete is one of the most widely used constructional materials. However, its tensile behavior in dynamic is yet not perfectly known. In order to design concrete structures and predict their collapse in the case of industrial accidents, it is mandatory to know its tensile strength. This property depends on the different solicitations to which the concrete can be exposed. In order to characterize the tensile strength of a R30A7 concrete and its dependence on the strain rate, three points bending tests are performed in static and dynamic cases. For this purpose, the most recent standards are used in the static tests. The dynamic ones are carried out with the split Hopkinson pressure bars. This device allows to perform dynamic tests with both the speed and effort loading measurements. Moreover a high speed camera is used to record these experiments in order to acquire full-field displacement measurements with the help of the digital image correlation. Tools using these fields are created to detect the apparition of the crack in one hand, and to follow the crack propagation in the other hand. All these experimental devices and the use of different models, some of which take in account the sample damage, make it possible to determinate the evolution of the tensile strength depending on the strain rate. This work brings forward the fact that ignoring the material damage increases the tensile strength obtain from the tests.

La corrosion de l'acier par carbonatation du béton est un phénomène de dégradation majeur des structures en béton armé, qui débute par la dépassivation de l'acier due à l'abaissement du pH de la solution interstitielle. Un modèle est été développé pour estimer la profondeur de carbonatation du béton. Le modèle proposé est un approfondissement de modélisations antérieures, notamment afin de prendre en considération dans les simulations l'effet de la température, tant par l’équation de transfert que par des termes de thermo-activation venant modifier les grandeurs de diffusion de dioxyde de carbone et des ions calcium en phase liquide, la solubilité des hydrates, la viscosité de l’eau, ainsi que l’isotherme hydrique. L’objectif étant d’inscrire la modélisation dans un cadre probabiliste, et donc coûteux en terme de calculs, il a fallu réduire la dimension stochastique du problème. Une méthodologie de choix des paramètres intervenant dans le modèle, basée sur une étude de sensibilité, a été proposée. Un modèle de substitution a été construit, à partir du modèle initial, pour déterminer les grandeurs intervenant dans les expressions des états-limites de dépassivation et d’initiation de la corrosion, s’appuyant sur des développements en chaos polynomiaux.Avec une définition de la probabilité d’amorçage de la corrosion et des modèles de substitution pour la profondeur carbonatée et pour l’amplitude de la variation annuelle du taux de saturation au voisinage des armatures, l’analyse fiabiliste proprement dite a été menée, notamment par rapport à l’incidence des conditions climatiques sur la fiabilité des ouvrages en béton vis-à-vis de la durabilité. / Corrosion of the steel by concrete carbonation phenomenon is a major degradation of reinforced concrete structures, which starts with the depassivation of the steel due to the lowering of the pH of the pore solution.A model was developed to estimate the depth of carbonation of concrete. The proposed model is a deepening of previous models, particularly to be considered in the simulations the effect of temperature, both by the transfer equation in terms of thermo-activation that modify dioxide diffusion of sizes carbon and calcium ions in the liquid phase, the solubility of hydrates, the viscosity of water and the water isotherm.The aim is to include in a probabilistic modeling framework, and therefore costly in terms of calculations, it was necessary to reduce the stochastic dimension of the problem. A methodology for the selection of parameters involved in the model, based on a sensitivity analysis, was proposed. An alternative model was built, from the original model, to determine the quantities involved in the expressions of borderline depassivation and corrosion initiation, based on developments in polynomial chaos.With a definition of the boot likelihood of corrosion and substitution patterns for carbonated depth and the amplitude of the annual variation in the degree of saturation in the vicinity of frames, reliability engineer the actual analysis was conducted, including compared to the impact of weather on the reliability of the fabricated vis-à-vis sustainability concrete.

Le béton de chanvre est aujourd'hui le matériau de construction agro-ressource le plus développé en Europe. Il se compose de chanvre et de liant minéral (chaux) mélangé à l'eau. Généralement, il est utilisé pour ses propriétés d'isolation thermique dans le bâtiment. La plupart des blocs de béton de chanvre qui ont été étudiés, présentent un comportement fragile et une très faible résistance mécanique. Les formulations sont généralement riches en liant et légèrement compactées. Jusqu'à présent, le béton de chanvre n'est pas considéré comme un matériau porteur. Il est principalement utilisé comme remplissage isolant, combiné avec des composants de structure en bois, béton ou maçonnerie. Une étude a testé d'autres formulations, avec des teneurs plus élevées en granulats grâce à un procédé de compactage, afin d'améliorer à la fois la rigidité et la résistance des mélanges durcis. Dans ces formulations, l’ajout des granulats de chanvre, plus légers et plus poreux que la chaux, abaisse de manière significative la conductivité thermique. Le présent travail est une étude expérimentale du comportement à la compression et au cisaillement du béton de chanvre, afin d’utiliser ce matériau bio-sourcé dans le contreventement des bâtiments à ossature bois, tout en maintenant de bonnes qualités d'isolation thermique dans le bâtiment. Deux formulations compactées, M1 et M4 ont été expérimentées, ainsi que des éprouvettes obtenues à partir de blocs de commerce Chanvribloc®. Deux séries d’essais ont été réalisées. La première est portée sur la compression uni-axiale dans chaque direction pour caractériser l'anisotropie mécanique du matériau. Cette anisotropie a été engendrée par le procédé de compactage. La deuxième série d’essais permet de caractériser le comportement de cisaillement des formulations étudiées. Dans cette étude, un dispositif spécial d’essai de cisaillement a été développé. Il permet de caractériser au cisaillement des éprouvettes sous différentes contraintes normales appliquées. Les champs de déformations des éprouvettes cisaillées ont été suivis par stéréo- corrélation d’images durant les essais. Les résultats expérimentaux de compression ont montré que ce matériau est anisotrope, même lorsqu'il est industriellement mis en place par vibrations. Le matériau a plus spécifiquement un comportement isotrope transverse. Le comportement dans le sens longitudinal est caractérisé par une ductilité très élevée, tandis que le comportement transversal est très fragile, avec un comportement très variable et instable. Les résultats expérimentaux en cisaillement montrent une ductilité élevée de ce matériau. Ce comportement est intéressant pour le contreventement et le comportement sous action sismique des bâtiments avec des murs constitués de béton de chanvre. Des modélisations et applications numériques à l’échelle structurelle d’un bâtiment à plusieurs étages ont été réalisées, pour illustrer l’utilisation des blocs de béton de chanvre en contreventement de bâtiments à ossature bois. Les formulations les plus compactées présentent un meilleur comportement sous actions sismiques modérées et moyennes, par rapport aux formulations les moins compactées à la mise en œuvre, tandis que les murs en Chanvribloc à l’état actuel, ne permettent pas de contreventer les bâtiments en zones sismiques modérés ou moyennes. / Lime and hemp concrete (LHC) is nowadays the most developed bio-based aggregate building material in Europe. It consists of hemp shiv and mineral binder mixing with water. Generally, bio-based materials like LHC are used for their thermal insulation properties in building. Most blocks of Lime Hemp Concrete which have been studied, show a brittle behavior and a very low mechanical strength. The formulations are generally rich in binder and slightly compacted. Up to now, this material is then not considered as a load bearing material and is mainly used as filler insulation, combined with structure components made of wood, concrete or masonry. A study has tested other formulations, with higher contents of aggregates thanks to a compaction process, in order to improve both the rigidity and the strength of the hardened mixtures. In these formulations, shiv which has higher amount is definitely lighter and more porous than lime, which prevents a significant increase in thermal conductivity. The present work of my PhD is an experimental study of the compressive and shearing behavior of hemp concrete, in order to study the load-bearing capacity and bracing of this bio based material, while maintaining good qualities of thermal insulation in building. Two compacted formulations were tested M1 & M4, as well as samples obtained from trade-blocks Chanvribloc®. Two series of tests were performed. The first one is a uniaxial compression test in each direction for characterizing the mechanical anisotropy of the material. This anisotropy is induced by the compacting process. The second one permits to characterize the shearing behavior of the different mix-designs. In this study, an original shear device was developed, specifically designed for this kind of material, which allows shearing under controlled normal stress. An image processing performed was carried out, using a camera and ARAMIS image processing software during shear tests, to evaluate the fields of deformations and to study the behavior of the specimen during the shear test. The compressive experiments results have shown that this material is anisotropic, even when it is industrially molded by vibrations. The material has a transverse isotropic behavior. The behavior in the longitudinal direction is characterized by very high ductility, while the transverse behavior is very brittle, with a highly variable and unsteady behavior. The experimental results in shear show a high ductility of this material. These results are very promising, an interesting behavior of LHC walls in term of potential bracing. Numerical modeling and applications have been carried out to illustrate the use of hemp concrete blocks for bracing buildings. The formulation M4 exhibits a better behavior under moderate and average seismic actions, compared to the formulation M1, while the Chanvribloc walls in the present state do not allowthe buildings to be braced in moderate or medium seismic zones.

Le béton est le matériau de construction le plus utilisé au monde. C’est un matériau composite hétérogène constitué par un squelette granulaire, enrobé dans une pâte de ciment hydraté. Cette pâte présente une microstructure différente à proximité des granulats délimitant ainsi une zone appelée « Auréole de transition ». Malgré les nombreux efforts fournis par la communauté scientifique internationale pour explorer ce matériau complexe, il reste toujours des zones d’ombres pour maîtriser les propriétés intrinsèques des trois phases qui le composent mais aussi l’influence de chacune d’elles sur le comportement global du matériau. L’objectif de cette thèse est, d’abord, d’étudier l’effet de la zone de transition et de la nature des granulats sur le comportement global du béton et, enfin, de caractériser la matrice cimentaire. Le point de départ est l’utilisation du MEB (Microscope Electronique à Balayage) pour analyser la zone de transition, ce qui a permis de voir que cette zone est fortement influencée par la nature des granulats et que la qualité de l’adhérence matrice/granulats n’est pas toujours parfaite. Un béton numérique 3D est ensuite développé dans le code de calcul aux Eléments Finis Abaqus pour quantifier l’effet de la zone de transition et de l’interface matrice/granulats sur les propriétés mécaniques du béton. Les résultats des simulations ne montrent pas d’influence de la zone de transition autour des granulats sur le comportement global en compression du béton. En revanche, une influence significative de la nature du contact matrice/granulats est démontrée lorsqu’un glissement entre la matrice et les granulats est pris en compte. Dans le but de trouver les propriétés de la matrice cimentaire qui enrobe les granulats, l’essai de micro-indentation est couplé avec une simulation numérique. La corrélation finalement obtenue entre le modèle numérique et l’expérience a permis de conclure sur la faisabilité de la méthodologie adoptée. En dernier lieu, l’essai de micro-indentation est appliqué sur des échantillons de béton afin d’étudier l’effet de l’incendie sur les propriétés de la matrice cimentaire. / Concrete is a construction material the most widely used. This is a heterogeneous composite material consisting of a granular skeleton embedded in a hydrated cement paste. This paste has a different microstructure near aggregates thus defining an area called «Interfacial Transition Zone». Despite the many efforts by the international scientific community to explore this complex material, there are still shadow areas to control the intrinsic properties of the three phases that compose but also the influence of each on the overall behavior of material. The objective of this thesis is, first, to study the effect of the transition zone and the nature of the aggregates on the overall behavior of concrete, and finally to characterize the cement matrix. The starting point is the use of SEM (Scanning Electron Microscope) to analyze the transition zone, which enabled us to see that this area is strongly influenced by the nature of the aggregates and the quality of adhesion matrix / aggregates is not always perfect. A 3D numerical concrete is then developed in the computation code Finite Element Abaqus to quantify the effect of the transition zone of the matrix and / aggregate interface on the mechanical properties of the concrete. The simulation results showed no influence of the transition region around the aggregates on the overall behavior of the concrete in compression. However, a significant influence on the nature of the contact matrix / aggregates is demonstrated when a sliding between the matrix and the aggregate is taken into account. In order to find the properties of the cementitious matrix which coats the aggregate, the micro-indentation test is coupled to a numerical simulation. Finally obtained the correlation between the numerical model and the experiment was concluded on the feasibility of the methodology adopted. Finally, the micro-indentation test is applied on concrete samples in order to study the effect of the fire on the properties of the cementitious matrix.