Depuis les années 2000, les grandes entreprises routières axent leurs recherches sur l’abaissement des températures de fabrication et de mise en œuvre des enrobés bitumineux à chaud (de 30 à 50°C). Le développement de ces nouveaux enrobés, dits tièdes, a fait apparaître sur les chantiers des problématiques de maniabilité qui n’existaient pas dans le cas des enrobés à chaud, notamment lors des mises en œuvre manuelles. Ce sujet de thèse, inscrit dans cette thématique des enrobés bitumineux tièdes, vise à étudier leur comportement aux températures de mise en œuvre et à développer une démarche de caractérisation et d’évaluation de leur maniabilité. Pour cela, le travail expérimental a été réalisé à différentes échelles du matériau (liant, mastic et enrobé), sur des matériaux réels (aux liants bitumineux) et modèles (aux huiles de silicone), en s’articulant autour de deux axes principaux : les propriétés de viscosité des liants et des mastics d’une part, puis les propriétés de maniabilité des enrobés évaluées par un outil depuis peu normalisé, à savoir le maniabilimètre. Après un état de l’art sur les enrobés bitumineux, notamment tièdes, leur mise en œuvre et méthodes de caractérisation, et les propriétés rhéologiques des liants et des mastics bitumineux, une présentation des différents matériaux utilisés est faite. Les études rhéologiques menées sur liant et sur mastic sont présentées dans une première partie, depuis la mise en place des protocoles de mesure en plan-plan jusqu’à l’analyse des différents comportements, en fonction de paramètres choisis tels que la température, le taux de cisaillement, le taux de fines ou la présence d’additif tiède. Outre la vérification du caractère newtonien des bitumes et la validation des matériaux modèles, cette partie met en évidence le comportement non newtonien des mastics aux taux de fines testés, ainsi que la présence d’un phénomène de sédimentation dans les mastics, particulièrement à haute température, qui amène à s’interroger sur la pertinence de l’étude à l’échelle mastic par rapport à celle sur liant. En deuxième partie, l’analyse de la maniabilité à l’échelle de l’enrobé est menée à l’aide du maniabilimètre (NF P 98 258-1) ; l’intérêt de maîtriser la compacité de l’échantillon pour une bonne pertinence de l’essai est démontré. Une analyse de différents paramètres, tant géométriques que produits, initialement sur enrobés modèles puis réels, a permis de mettre en évidence la capacité et les limites de cet outil à caractériser la maniabilité, en corrélation avec les études rhéologiques sur liant et mastics / Since the 2000s, road industries have focused their researches on lowering the mixing and implementation temperatures of Hot Mix Asphalt (HMA) (from 30 to 50°C). These new asphalt concretes, called Warm Mix Asphalt (WMA), created a workability issue that did not exist in the case of HMA, especially during manual implementation. This thesis aims to study the behavior of these WMA at implementation temperatures and to develop a method to characterize and evaluate their workability. For that, the experimental work was done at several scales of the material (the binder, the mastic and the mixture), some made with bituminous binders and some with silicone oils. Two properties were studied: on the one hand the viscosity of binders and mastics, and on the other hand the workability of mixtures measured by the workability device, newly standardized. After a state of the art on asphalt concretes, in particular WMA, on their implementation and characterization techniques, on the rheological properties of bituminous binders and mastics, the different materials used are presented along with their characterizations. The rheological studies conducted on binder and mastic are exposed in a first part, from the setup of measure procedures to the analysis of different behaviors with respect to the chosen parameters such as temperature, shear rate, filler content. This part highlights not only the Newtonian nature of binders but also the non-Newtonian behavior of mastics and the sedimentation phenomenon they endured at high temperatures which leads to investigate the legitimacy of the study at the mastic scale. In a second part, the workability of the mixtures is measured with the workability device (NF P 98 258-1), showing the importance of controlling the void content of the sample to guaranty a relevant test. An analysis of several parameters highlighted the ability and the limits of this device to characterize workability, with regard to the rheological studies on binders and mastics

<div>Aluminum alloy sheets are typically manufactured from cast slabs by multi-step rolling and annealing process. This process is very energy intensive, especially in the homogenization process after casting, which usually is conducted at 480 to 580 ℃ for up to 48 h. To reduce the </div><div>processing steps and energy, a shear-based single-step deformation process, large strain extrusion machining (LSEM), was used to create strips from AA6013-T6 with and without preheating of the workpiece. Continuous strips were obtained from this alloy with low workability. Flow patterns through the thickness of the strips exhibited primary shear with grains inclined steeply to the faces of the strips, modified to varying degrees by secondary shear from friction with the tools at the surfaces. Through control of the deformation parameters (strain, strain rate and temperature), a wide range of microstructure could be achieved. In high-temperature LSEM, dynamic recrystallization occurs at lower temperatures than in commercial hot rolling processes. </div><div><br></div><div>LSEM was performed directly on the as-cast AA6013 without homogenization. By appropriate combination of strain and strain rate, continuous strips were obtained in a single step without preheating directly from the as-cast workpiece. The highly deformed LSEM strip has enhanced workability. It can be cold rolled with at least 73% reduction in a single step without cracking. The strips were characterized by strong shear texture with partial {111} and <110> fibers. After annealing, a mixed texture containing simple shear texture and other texture develops. The annealed strips are expected to have better formability than commercial ones made by rolling.<br></div><div><br></div><div>In comparison, multi-step warm-rolling and cold rolling were performed on the as-cast AA6013. The as-cast material was preheated to 300 ℃ and rolled with 12% reduction per pass till the same effective strain as the LSEM. The warm-rolled strips were then cold-rolled with the same reductions as those on LSEM strips. The results showed that during warm rolling process, cracking occurs on the strips before reaching the same effective strain and the warm-rolled strips can only be further cold rolled with reduction less than 26% before cracking, compared with 73% reduction without cracking for LSEM strips.<br></div><div><br></div><div>Based on the simple shear LSEM process, a novel way to produce aluminum strip/sheet material is introduced. The alloys are cast into disk-shape workpiece and then transferred to the LSEM line. In this line, continuous strips/sheets are obtained in a single step at room temperature. The materials are then coiled if needed and cold rolled to the final gauge. Finally, the strips/sheets are solution treated for further deformation processing. In this method, the conventional homogenization and hot rolling, including reversing and multi-stand hot rolling, are replaced by a single-step LSEM process at room temperature.<br></div>

Les enjeux économiques liés à la hausse des coûts des ressources fossiles, leur raréfaction, et les impacts environnementaux inhérents à leur fabrication et à leur utilisation, conduisent les acteurs de la construction à s’orienter vers des matériaux biosourcés. Les ressources issues de la biomasse sont alors au premier plan, celles agricoles notamment, dont les fibres provenant des tiges des plantes. Parmi ces fibres, le lin se démarque en raison de ses propriétés mécaniques élevées et sa faible densité, et sa disponibilité en Normandie. L’objectif de cette étude est de développer un matériau composite innovant par l’association des fibres de lin à une matrice cimentaire, qui sera utilisé dans des procédés de construction préfabriquée. Après la caractérisation fine des constituants de départ, nous avons d’abord décrit en détail l’élaboration des mortiers et bétons biofibrés avec un focus sur la méthodologie de formulation. Puis nous avons analysé l’influence de l’incorporation des fibres de lin sur les propriétés rhéologiques (air occlus, consistance, ouvrabilité et fluidité) et physico-chimiques (pH, ATG). Les propriétés physiques (porosité, module d’élasticité) et mécaniques (contraintes à la rupture, indice de ténacité) ont été mesurées par des essais de flexion et de compression à l’état durci. Ces résultats montrent nettement que la présence des fibres de lin réduit de façon importante les propriétés technologiques des pâtes cimentaires, du fait la sensibilité des fibres au milieu très alcalin et de leur caractère fortement hydrophile. Bien que les traitements de surface des fibres expérimentés (plasma atmosphérique, enrobage coulis de ciment et laitier de hauts fourneaux ou à l’huile de lin) aient permis d’améliorer certaines propriétés des mortiers, ils n’ont pas permis de réduire dans le temps la dégradation des fibres au sein de la matrice cimentaire (hydrolyse alcaline des fibres et leur minéralisation sous l’action de l’hydroxyde de calcium). Il apparaît donc nécessaire de recourir à des liants alternatifs pour tenter d’améliorer la durabilité de ces biocomposites à fibres végétales. Ainsi, de nouvelles formulations de mortiers et bétons sont proposées, dans lesquelles le ciment Portland est remplacé partiellement par le métakaolin / le laitier de hauts fourneaux ou totalement par un ciment sulfo-alumineux, sans préjudices pour le comportement rhéologique. L’étude des nouveaux composites formulés avec le métakaolin ou le ciment sulfo-alumineux indique des niveaux de résistance mécanique et de ténacité élevés. Leurs résistances au gel supérieures au béton classique ou celui incorporant des fibres de verre tient à la forte teneur en air (les fibres jouent un rôle d’agent entraîneur d’air). / The economic issues linked to the rising costs of fossil resources, their scarcity, and the environmental impacts inherent in their manufacture and use, are leading the construction industry to move towards bio-based materials. The resources from biomass are then in the foreground, especially agricultural ones, including fibres from plants stems. Among these fibres, flax stands out because of its high mechanical properties and low density, and its availability in Normandy. The objective of this study is to develop an innovative composite material by combining flax fibres with a cement matrix, which will be used in prefabricated construction processes. After the fine characterization of the initial constituents, we first described in detail the development of plant fibre-reinforced mortars and concretes with a focus on the formulation methodology. Then we analysed the influence of the incorporation of flax fibres on the rheological properties (entrapped air, consistency, workability) and physico-chemical properties (pH, ATG). The physical properties (porosity, modulus of elasticity) and mechanical properties (compressive and tensile strength, toughness index) were measured by bending and compressive tests in the hardened state. These results clearly show that the presence of flax fibres significantly reduces the technological properties of cementitious pastes, because of the sensitivity of the fibres to the highly alkaline medium and their highly hydrophilic nature. The surface treatments of the experimental fibres (by using atmospheric plasma, cement grout coating, blast furnace slag or linseed oil) have effectively improved some properties of mortars, the degradation of the fibres within the cement matrix remain active over the long term (alkaline hydrolysis of the fibres and their mineralization under the action of calcium hydroxide). It therefore appears necessary to use alternative binders in an attempt to improve the durability of these plant fibre biocomposites. Thus, new formulations of mortars and concretes are proposed, in which the Portland cement is partially replaced by metakaolin / blast furnace slag or totally by sulfoaluminate cement, without prejudice to the rheological behaviour. The study of the new composites formulated with metakaolin or sulfoaluminate cement indicates high levels of mechanical strength and toughness. Their resistance to frost superior to conventional concrete or concrete incorporating glass fibres is due to the high air content (the fibres act as an air-entraining admixture).

Concrete in Sweden has traditionally been manufactured with natural aggregate from glaciofluvial eskers. There is a need to preserve the remaining eskers because of their cultural value and importance for water filtration, thus natural aggregate has to be replaced. The most realistic alternative is to use crushed rocks. The major problem with crushed rocks in concrete production is the workability. This is because crushed rocks have less favorable properties. The fragments are flakier and have a rougher surface than natural aggregates that have been rounded in water. Without any amelioration of the crushed rock, to reach a certain workability and strength, the amount of cement in the mix has to be increased. Cement production requires large amounts of energy and the decarbonation of limestone releases large amounts of CO2. Combined, the release of CO2, due to burning and decarbonation of limestone, accounts for about 5% of the global CO2 emissions. An increase in cement consumptions is less desirable. Thus to replace natural aggregates, the use of crushed rocks has to be optimized as regard cement consumption. Several crushed aggregates, most from granitic rocks, from all over Sweden were analysed in this study. These crushed rocks were characterized according to their grading, specific surface, shape and petrography and compared to natural sand. Rheological tests that reveals the workability in detail was performed on mortars. The tests showed that as regard workability the 0-2 mm fraction is the most important factor. Further, the maximum aggregate size was gradually increased up to 16 mm, to have a more realistic approach to the concrete produced by the building industry. The results showed that with grading optimization and superplasticizer, some crushed rocks can be used for concrete production without increasing, and even decreasing, the cement consumption. This research also contemplated the use of filler. As a mineral admixture it can improve the compressive strength. It can also be used to replace cement; a replacement up to 20 kg/m3 of cement by filler can be done without significant effect on compressive strength.

An increase in environmental awareness and energy concerns had recently prompted efforts to make pavement construction cheaper and more environmentally friendly. Warm mix asphalt (WMA) is an asphalt mixture production technology that promises to reduce production costs and greenhouse gas emissions. Foamed asphalt binder is increasingly being used to produce WMA. This dissertation addresses several issues related to the use of foamed asphalt binder for WMA applications. The first objective of the research presented in this dissertation is to develop a method and metrics to precisely quantify the characteristics of asphalt binder foams. Laboratory measurements were obtained using the newly developed method to evaluate the extent and stability of foams produced using different asphalt binders at different water contents and laboratory foaming devices. Results demonstrate that the method developed is promising in terms of its ability to provide a detailed history of the behavior of foamed asphalt binder as the foam collapses. In addition, results indicate that the method is sensitive to distinguish between foaming characteristics of different asphalt binders as well as different water contents and foaming devices. The second objective of this study was to relate intrinsic properties of the asphalt binder to its foaming characteristics. A physical model was developed for expansion of asphalt binder foam based on foam physics and fluid mechanics of micro-droplets. The model relates foamant water and asphalt binder mixing efficiency with the surface tension of the asphalt binder. The model can be used to predict which binder can be effectively foamed and used, and whether any chemical modification to the binder is necessary to achieve the same. Results indicate that only a small percentage of water is effective in foaming the asphalt binder. The last objective of this research was to evaluate the influence of foaming on asphalt binder residues and mixture workability and coatability. The influence of foaming process on the rheological properties of asphalt binder residue was investigated. In addition, the significance of foamed asphalt binder characteristics on mixture workability and coatability was evaluated. Results from this last part of the study can be used to optimize binder foaming such that the resulting mixture is coated and compacted without compromising performance. / text

Improving on our construction practices to promote sustainable development in engineering and to promote eco-friendly living is vital in the fight against global warming and associated problems. This study looked at one of the ways in which engineering can contribute to this fight through promoting the recycling of waste by-products such as fly ash (FA), on a larger scale in the cement and concrete industry, by utilizing the FA to the optimum. In this study concrete mixes of 25 MPa, 35 MPa and 50 MPa with FA partially substituting the cement at 30%, 40%, 50% and 60% were produced and numerous tests were performed to determine the optimum amount of FA that can be used and still obtain better or comparable concrete to ordinary concrete. Testing for concrete properties was conducted under laboratory conditions over a period of one year. In addition, a cost comparison between ordinary concrete and FA concrete was undertaken. The results obtained show that the increase in FA content influenced the rheological properties of fresh concrete favorable. The recorded slump increased with the increase of FA content. Increasing the FA content prolonged the setting of concrete, with the ordinary concrete taking 1 hour 45 min to set, compared to more than 2 hours for FA mixes. The FA increase had negligible effects on the air content of the concrete mixes. The drying shrinkage of concrete increased with the increase of FA content, with the strain ranging from 0,045% to 0,56%. The compressive strength results show that the control mixes with 30% FA content attained the highest compressive strength over a year. In some cases, the 40% FA strength was compatible to the 30% FA strength. The durability index results showed the control mix of 30% FA attaining better results for Oxygen Permeability Index and Sorptivity Index, with the 40% FA mix following closely. The higher FA content mixes (50% and 60%) attained better Chloride Conductivity results than the lower FA content mixes. Increasing the FA content does affect the performance of the concrete at early stages, however concrete with acceptable strength and good durability qualities can be produced even with 50% FA volume. Increasing the FA content can also significantly reduce the cost of producing and working with concrete. The practice of utilizing higher FA content in concrete can be beneficial for the South African cement and concrete industry without compromising the quality of the cement products concrete structures. / M

Un des problèmes de mise en œuvre des bétons rencontrés sur des chantiers de pieux forés à la tarière creuse est la difficulté d’introduire la cage d’armatures dans le béton frais dans 15 % des cas. Cette difficulté est liée en partie au comportement rhéologique du béton et au phénomène de ressuage qui sont des problèmes de formulation du béton. En effet, des études sur des fluides à seuil (pâtes de ciment, solutions de Carbopol, émulsions) comme le béton, montrent une corrélation entre le déplacement d’objets dans ces fluides et leurs seuils de cisaillement.L’objectif de cette étude est de développer un outil de caractérisation du béton sur chantier qui permette de tester la capacité des armatures à être introduites dans le béton à partir d’une technique basée sur le principe de la pénétrométrie. Une formulation de base de béton pour pieux a été choisie sur chantier et modifiée en laboratoire de façon à obtenir des bétons aux comportements variés (seuil de cisaillement, perte d’ouvrabilité et thixotropie) représentatifs des conditions sur site. L’influence de ces différents paramètres rhéologiques sur l’enfoncement des armatures a été étudiée. Elle a permis d’identifier des valeurs seuils pour lesquels un refus d’enfoncement de la cage d’armatures (blocage) est observé : slump<18 cm; τs>780 Pa et τ0>340 Pa.Une étude complémentaire menée sur 4 chantiers de pieux forés à la tarière creuse a permis de valider et d’affiner les conclusions précédentes et de prédire les blocages éventuels. / This study is mainly concerned with a concrete placement problem encountered on continuous flight auger (CFA) pile, namely the difficulty of introducing a reinforcement cage into fresh concrete, difficulty that occurs in 15 percent of cases. These difficulties are correlated in part with the rheological behavior of the concrete as well as with the bleeding phenomenon, both of which pertain to concrete mix design problems. Indeed, studies carried out on yield stress fluids, like concrete, reveal a correlation between object displacements in these fluids and their actual yield stresses.The aim of this study is to develop a tool for the in situ characterization of concrete at rest, based on the principles of penetrometry, which can assess the capability of introducing reinforcements into concrete.A widespread pile concrete mix design was chosen on-site and modified in the laboratory to obtain concrete mixtures with various behavior (yield stress, loss of workability and thixotropy) which are representative of on-site conditions. The influence of these rheological properties on the reinforcement embedment capacity has been studied. For low viscosity values (6 to 12 Pa.s), the rejection of reinforcement becomes a real risk for some threshold values : slump<18 cm; τs>780 Pa and τ0>340 Pa. To avoid blocking τ0 should be limited during casting process.An additional study was conducted on CFA piles on-site and helps to validate previous findings. It also describes reinforcement embedment kinetic. A correlation was found between reinforcement depreciation period during its setting and concrete viscosity.

I kallasfalt med hårt basbitumen bryter vattnet ut ur bitumenet och bindemedlet i massan stelnar olika snabbt beroende på vilket stenmaterial asfaltsmassan består av. Om brytningen sker innan utläggning blir massan obearbetbar, målet är att brytningsprocessen ska kunna styras genom att massans brytningsprocess skall vidta när energi tillförs i massan via en vibratorsvält som packar massan. Från tidigare tester är hypotesen att det är stenmjölet som styr brytningsprocessen och bearbetbarheten. Idag är problemet att massan bryter för snabbt och den blir svårbearbetad vid läggning och resultatet blir dåligt. I arbetet undersöks också täckningsgrad och styvhetsmodulen. Arbetet är utfört på NCC:s väglaboratorium i Umeå 4/4 - 15/4 2016. Sex stycken stenmaterial från olika bergtäkter med olika egenskaper testas. Bergtäkterna är belägna från Närke upptill Västerbotten vid namn Dylta, Råsta, Sälgsjön, Stöningsberget, Ljusberget och Supartallen.  Fraktion 0-16 mm från en och varje bergtäkt handblandas, två asfaltsprover tillverkas enligt två olika mix- och bedömningsmetoder. Täckningsgrad, bearbetningsegenskaperna och brytningprocessen bedöms och antecknas i en matris. I nästa steg ersätts ordinarie stenmjöl (0-2 mm) med stenmjöl från en bergtäkt med ett tidigare känt bra stenmaterial. Med resterande makadam (2-16 mm) görs samma process om på nytt och resultatet analyseras och jämförs. En asfaltsmassa med stenmjöl från bergtäkten Supartallen och makadam från bergtäkten Stöningsberget visar förbättrade resultat i jämförelse med fraktion 0-16 mm från bergtäkten Stöningsberget och vidare laborationstester görs på denna blandning av stenmaterial. Dessa bergtäkter ligger geografiskt nära varandra, drygt 25 mil, vilket också motiverar till att välja dessa stenmaterial som i framtiden kanske kommer användas fullskaligt. Från dessa blandningar tillverkas asfaltskroppar genom packning med gyratorisk packare och styvhetmodulen testas. I ekonomisk och miljömässig vinning görs ett försök med en restprodukt från stålindustrin. Ett försök utförs med skänkslagg (0-2 mm). Slaggen blandas med stenmaterial från bergtäkten Supartallen där bearbetningen, brytprocessen och täckningsgraden undersöks. Detta är ett inledande försök för att få en fingervisning hur asfaltsmassan beter sig blandat med skänkslagg. Utvärdering av resultaten gjordes med hjälp av en matriser där varje asfaltsblandning ingår. Asfaltsblandningen betygsätts enligt bearbetbarhet, täckningsgrad och brytningskontroll. Skålen analyserades och slutsatser om brytningen kunde dras. Genom sönderdelning av massan kunde observationer göras om hur brytningen av massan har kommit, även täckningsgraden analyseras. Resultaten pekar på att stenmjölet har en betydande roll i täckningsgrad, brytning vid blandning och brytningsprocessen, dock ingen skillnad på styvhetsmodulen. Att enbart stenmjölet ska vara problemet är inte hela sanningen men har som sagt en betydande roll. Just att stenmaterial från Supartallen är så pass bra för beaktas och använda sig av stenmaterial med liknande egenskaper och inte använda stenmaterial med för höga halter SiO2 då det ger dålig täckningsgrad. Att massan bryter för snabbt kan bero på halten bindemedel, vidare laborationer bör göras med halten bindemedel i fokus. / In cold asphalt with hard base-bitumen the water breaks out from the bitumen and the binder in the mass solidifies at different rates depending on the containing stone material in the asphalt. If the break occurs before laying the mass becomes unworkable. The intention by this examination is control this process by the mass extraction process should take place when energy is supplied into the mass through a vibrator famine. From previous tests the hypothesis is that the rock flour controls the breaking-process and the workability. Today, the problem is that the mass curing process starts too early and it becomes difficult to manage and work with and the results of the paving are bad. The thesis project also examines coverage and stiffness module, it’s performed on the NCC's road laboratory in Umeå 4/4 - 15/4 in 2016. Six stone materials from different quarries with different properties are tested. Fraction 0-16 mm from each rock quarry are handmixed, two asphalt samples produced by two different mixing- and assessment-methods. Coverage, workability and the breaking-process are assessed and recorded in a matrix. Next, replaced ordinary rock flour (0-2 mm) with rock flour from a quarry of a previously known good stone material. With the remaining makadam (2-16 mm) the process are made all over again and the results are analyzed and compared. An asphalt with rock flour from quarry Supartallen and the remaining makadam from quarry Stöningsberget shows improved results compared with fraction 0-16 mm from quarry Stöningsberget and further tests in laboratory are made with this mixture. These quarries are geographically fairly close to each other, 250 km (about 150 miles), which motivates to choose these quarries for a full scale-test in the future. From these mixtures asphalt-bodies are manufactured by gasket with gyratory compactor and stiffness module is examined. In the economic and environmental profit attempts are made with a residue from the steel industry. An attempt carried out with the slag from ladles (0-2 mm). The slag is mixed with stone material from quarry Supartallen where workability, breaking process and coverage is investigated. This is an initial attempt to introduce how the asphalt mixture behaves mixed with the slag. An evaluation was made with matrix where each asphalt mixture included. The asphalt mixture is graded according to machinability, coverage and breaking control. The bowl was analyzed and conclusions about the break could be drawn. Analyzes of the curing process and coverage was made by dismemberment of the mass. The results indicate that the rock flour has a significant role in coverage, extraction at mixing and mining process, however, the stiffness module has the same results in all mixtures. The mere stone flour shouldn’t be the problem but still has a significant role. At the aggregate of Supartallen is so good for the consideration and use of stone materials with similar properties and not rock material with a high amount of SiO2 as it provides poor coverage. The mass harden too quickly may depend on the content of binder, further laboratory work should be done with the binder content in focus.

This thesis deals with refractory concrete binding system based on aluminous cement and phosphoric acid. The prepared refractory concretes were fired at 1 000 °C. Various effects on compressive strength of refractory concrete were studied. The influence of aluminous cement content and phosphoric acid content, the influence of various admixtures, the influence of plasticizers and the influence of time and method of sample storage were studied. Simultaneous thermogravimetry and differential thermal analysis of the basic unfired sample were performed. Finally, selected refractory concretes were fired at 110, 200, 400, 600, 800, 900, 1 000 and 1 100 °C. The compressive strength of these samples was measured and powder X ray diffraction analysis was performed. The compressive strength of refractory concretes under intermediate temperatures (800–1 100 °C) was most increased in samples with metakaolin and gray microsilica.

Concrete is one of the world’s most common construction materials and is composed of 70-80 % stone material. Today crushed stone is used as aggregate in concrete in order to replace natural aggregates due to strong environmental reasons. Stone crushing yields flaky material and in this thesis studies are made on the flaky particle shape and how it influence properties of concrete such as workability, rheology and strength. The concrete recipes used in this thesis have fixed values, the only variable is the flakiness of the crushed stone. Flakiness is varied between 0 %, 17 %, 50 %, and 100 % in turn for the individual size fractions 2-8 mm, 8-10 mm, 10–12.5 mm, and 12.5–16 mm. By using Swedish and European standards one determines flakiness index, packing factor, slump test, Thaulow tester, compression strength and flexural strength. The Bingham model is applied with the use of a viscometer to determine the concretes rheological properties such as plastic viscosity and yield stress. For the individual size fraction 12.5-16 mm a flow analysis is performed in an L-box to study how the particles are orientated with the flow direction, and how this influences the strength and crack length. Results show that the loose packing factor decreases with increased flakiness for all individual size fractions. Fractions 2-8 mm and 8-10 mm need a small increase in super plasticizer with increased flakiness to achieve 200 mm slump. The larger individual size fractions do not show any increase in super plasticizer regarding this matter. The Thaulow tester indicates constant values with increased flakiness for all individual size fractions except 2-8 mm were a weak increase is observed. Values of the plastic viscosity are indicated unchanged as the flakiness index is increased for all individual size fractions except 2-8 mm that slightly increase for 100 % flakiness. The yield stress behaves unchanged with increased flakiness for all individual size fractions except 12.5-16 mm which significantly decrease for 100 % flakiness. When the concrete flows in the L-box an image analysis concludes that the larger amounts of flaky particles are orientated with the flow direction. The crack length increases with higher flakiness for fraction 12.5-16 mm but this does not lead to an increase in strength. Flexural strength increase with higher flakiness, this is clearly observed for the two largest individual size fractions. Compressive strength is indicated to be independent of flakiness and is approximately constant for all individual size fractions except individual size fraction 12.5-16 mm that indicates an increase. High flakiness on cone crushed granite rock in size fraction 8-16 mm from the bedrock in Enhörna is not regarded as disadvantageous for concrete manufacturing, as it shows good values in workability, rheology and strength. / Betong är ett av världens vanligaste byggmaterial och består av ungefär 70-80 % stenmaterial. Idag används krossten som ballast i betong för att ersätta naturgrus av starka miljöskäl. Stenkrossning ger upphov till flisigt material och i detta arbete studeras den flisiga kornformen och hur den påverkar betongens egenskaper inom arbetbarhet, reologi och hållfasthet. Blandningsreceptet har fixerade värden och den enda variabeln som varierar i arbetet är flisigheten på krosstenen. Flisigheten varieras mellan 0 %, 17 %, 50 % och 100 % i tur och ordning för delfraktionerna 2-8 mm, 8-10 mm, 10–12.5 mm, och 12.5–16 mm. Genom att använda svenska och europeiska standarder bestäms flisighetsindex, packningsindex, sättmått, omformningstal, tryckhållfasthet och böjdraghållfasthet. Bingham modellen tillämpas för att med hjälp av en viskometer bestämma betongens reologiska egenskaper som plastisk viskositet och flytgränsspänning. För delfraktionen 12.5-16 mm utförs även flödesanalys med hjälp av en L-låda för att studera hur partiklar orienterar sig med flödesriktningen, och hur detta påverkar hållfastheten och spricklängden. Resultat visar att den lösa packningsgraden sjunker med ökad flisighet för samtliga delfraktioner. Fraktionerna 2-8 mm och 8-10 mm kräver en liten ökning av plasticerarmängden med ökad flisighet för att uppnå sättmått 200 mm. De större delfraktionerna visar dock ingen ökning av plasticerarmängd i detta avseende. Omformningstalet är i princip konstant med ökad flisighet för samtliga fraktioner förutom för 2-8 mm fraktionen där en svag ökning kan dokumenteras. Den plastiska viskositeten indikeras oförändrad då flisighetsindex ökar för samtliga delfraktioner förutom 8-10 mm fraktionen som ökar en aning vid 100 % flisighet. Flytgränsspänningen beter sig konstant med ökad flisighet för samtliga delfraktioner förutom 12.5-16 mm som signifikant sjunker för 100 % flisighet. När betongen flyter i L-lådan dras slutsatsen från bildanalys att den största delen flisiga partiklar orienterar sig med flödesriktningen. Spricklängden ökar med större flisighet för fraktionen 12.5-16 mm men detta visar ingen ökning i hållfastheten. Böjdraghållfastheten blir högre med ökad flisighet, denna trend visas tydligast av de två största delfraktionerna Tryckhållfastheten kan indikeras vara oberoende av flisighet och är ungefär konstant för samtliga delfraktioner förutom delfraktion 12.5-16 mm som indikerar en ökning. Hög flisighet på konkrossad granitsten fraktion 8-16 mm från bergtäkten i Enhörna anses inte vara ogynnsam för betongtillverkningen, då den ger goda värden på arbetbarhet, reologi och hållfasthet.