Le glycérol et le fructose sont des molécules qui peuvent être extraites facilement de labiomasse et en des quantités substantielles. Ce travail de recherche porte sur la déshydratationcomme moyen de valoriser ces composés. C’est dans ce but que des catalyseurs supportés suroxydes de zirconium et de titane, ainsi que des matériaux de type phosphate de calcium, ontété préparés et testés pour la réaction de déshydratation du glycérol en phase gazeuse. Desoxydes mixtes de niobium et cerium ainsi que des oxydes mixtes mésoporeux de Nb2O5-MeO2 (M = Ce, Zr, Ti) ont été également préparés et cette fois-ci testés pour la réaction dedéshydratation du fructose en milieu aqueux. Dans les deux cas, les propriétés acido-basiquesde surface des catalyseurs étudiés ont été corrélées à leur efficacité catalytique. / Glycerol and fructose are molecules that are readily available in substantial quantities fromthe biomass. In this work dehydration routes for valorization of these compounds wereinvestigated. Therefore, zirconia and titania based catalysts, and calcium phosphate materialswere prepared and evaluated in the glycerol dehydration in gas phase. Niobia-ceria mixedoxides and mesoporous Nb2O5-MeO2 (M = Ce, Zr, Ti) mixed oxides were prepared andtested in fructose dehydration reaction in aqueous phase. The surface acid-base properties ofthe studied catalysts were correlated to their catalytic performance.

The total annual forage production of tropical grasslands in the Brazilian Central area is expected to increase, however, some studies also predict a higher variability of forage production between and within years. In the future, maintenance of many pastures áreas will probably depend on the use of technology and increased productivity, seeking a competitive advantage concerning other activities, or even on its relocation to marginal áreas where forage grasses will be more suitable to abiotic factors. The water stress, both by flooding and drought, may reduce the production and survival of grasses. The objective was to identify the strategies that some genotypes of Paspalum and Urochloa genus use to cope with the flooding and/or water deficiency in the soil. Two greenhouse experiments were conducted: 1 - morphological and physiological characteristics, survival rate and recovery index in five genotypes of Paspalum sp. (BRS Guará, BGP 289, BGP 293, BGP 402 and BGP 397) and U. brizantha cv. Marandu were evaluated under three water conditions (flooded, drought and control); 2 - dehydration tolerance and dehydration avoidance of three cultivars of Urochoa (\'Marandu\', \'BRS Paiaguás\' and \'Basilisk\') and a cultivar Mediterranean Dactylis glomerata L. cv. Medly. In experiment 1, the genotypes of Paspalum sp., especially BGP 289, BGP 402, BGP 397 and cv. Marandu previously submitted water déficit, presented high tiller survival rates after rehydration. The cv. Marandu and BGP 289 access were not tolerant to flooding, presenting a low tiller survival rate and root recovery index. The BGP 293 access was not resistant to flooding, but it was able to survive periods up to 28 days under water depth. The accesses of Paspalum BRS Guará, BGP 402 and BGP 397 presented resistance mechanisms and survival to flooding, related to a high concentration of chlorophyll in the leaf, leaf biomass, and root recovery and tiller survival after a recovery period under water regular condition. In experiment 2, the distinction of cultivars was in accordance with the resource-use strategy. Cultivars of Urochloa were less tolerant to dehydration than cv. Medly. But the most productive Urochloa cultivars (Marandu and Basilisk) further delayed dehydration due to high investment in the root system, and consequently were less dehydration tolerant, with less survival rates under severe drought. The cv. BRS Paiaguás was less productive under regular irrigation than other Urochloa cultivars, but under drought conditions it is closer to the cv. Medly, being highly dehydration tolerant, and presenting high survival rates under severe drought and dehydration avoidance strategies with roots elongation along the soil profile during the drought period. There are differences in responses to other deficit and flooding between and within the Paspalum and Urochloa genus morphophysiological traits used in this study are relevant for the understanding of the mechanisms and discrimination among genotypes. / A partir de predições de futuros impactos climáticos, é esperado um aumento na produção anual total de forragem tropical, contudo estudos também predizem aumento da variação da produção entre e dentro dos anos. Diante desses cenários, é imprescindível buscar vantagens competitivas e o conhecimento do grau de tolerância a estresse abióticos de gramíneas tropicais. O estresses hídrico, tanto por excesso quanto por deficiência, pode reduzir a produção e a sobrevivência da planta forrageira. Assim, objetivou-se identificar as estratégias que alguns genótipos do gênero Paspalum e Urochloa utilizam para lidar com o encharcamento e/ou com a deficiência hídrica no solo. Foram conduzidos dois experimentos em casa-de-vegetação: 1 - avaliou-se características morfofisiológicas, taxa de sobrevivência e índice de recuperação em cinco genótipos de Paspalum sp. (BRS Guará, BGP 289, BGP 293, BGP 402 e BGP 397) e U. brizantha cv. Marandu sob três condições hídricas (alagado, déficit e controle), em vasos pequenos; 2 - mensurou-se em pequenos vasos a tolerância a desidratação e em longos tubos o atraso a desidratação de três cultivares de Urochoa (\'Marandu\', \'BRS Paiaguás\' e \'Basilisk\') e uma cultivar mediterrânea de Dactylis glomerata L. cv. Medly, submetidos a condições sem limitação hídrica e posteriormente sob seca prolongada. Sob déficit hídrico, os genótipos de Paspalum sp., especialmente o BGP 289, o BGP 402 e o BGP 397, e a cv. Marandu, apresentaram altas taxas de sobrevivência de perfilhos após reidratação. A cv. Marandu e o acesso BGP 289 não são tolerantes ao alagamento, apresentaram baixas taxas de sobrevivência e de recuperação radicular. O acesso BGP 293 não é resistente ao alagamento, porém é capaz de sobreviver a períodos de até 28 dias sob lâmina d\'água. Os acessos de Paspalum BRS Guará, BGP 402 e BGP 397 apresentam mecanismos de resistência e sobrevivência ao alagamento, relacionados à alta concentração de clorofila na folha, de biomassa de folhas, e de recuperação radicular e sobrevivência de perfilhos após período de recuperação sob condição hídrica regular. No experimento 2, a distinção dos cultivares foi de acordo com a estratégia de uso dos recursos. Cultivares de Urochloa são menos tolerantes a desidratação que a cv. Medly. Mas as cultivares de Urochloa mais produtivas (Marandu e Basilisk) atrasaram mais a desidratação, devido ao alto investimento no sistema radicular, e consequentemente foram menos tolerantes a desidratação, com memores taxas de sobrevivência sob seca severa. A cv. BRS Paiaguás é menos produtiva sob irrigação regular em comparação as outras cultivares de Urochloa, mas sob seca aproximou-se mais da cv. Medly, mostrando-se altamente tolerante a desidratação, com altas taxas de sobrevivência sob seca severa, além de apresentar estratégia de atraso a desidratação com o alongamento de raízes ao longo do perfil do solo durante a seca. Existem diferenças entre e dentro de espécies dos gêneros Paspalum e Urochloa em relação as respostas sob duas formas de estresse hídrico. As caraterísticas morfofisiológicas utilizadas neste estudo auxiliaram na compreensão dos mecanismos de resposta ao estresse hídrico e na discriminação dos genótipos.

No description available.

Introduction: Nurses and other health care professionals meet patients with heart failure (HF) who report they are thirsty. Thirst is described by the patients as a concern, and it is distressing. Currently there are no standardized procedures to identify patients with increased thirst or to help a patient to manage troublesome thirst and research in the area of thirst is scarce. In order to prevent and relieve troublesome thirst more knowledge is needed on how thirst is experienced and what factors cause increased thirst. Aim: The aim of this thesis was to describe the thirst experience of patients with HF and describe the relationship of thirst with physiologic, psychologic and situational factors. The goal was to contribute to the improvement of the care by identifying needs and possible approaches to prevent and relieve thirst in patients with HF. Methods: The studies in this thesis used a cross-sectional design (Study I) and prospective observational designs (II-IV). Studies include data from patients with HF who were admitted to the emergency department for deterioration in HF (I, IV) or visited an outpatient HF clinic for worsening of HF symptoms (III); others were patients who were following up after HF hospitalization (II), and patients with no HF diagnosis who sought care at the emergency department for other illness (I). Patients completed questionnaires on thirst intensity, thirst distress, HF self-care behaviour, feeling depressive and feeling anxious. Data on sociodemographic, clinical characteristics, pharmacological treatment and prescribed fluid restriction were retrieved from hospital medical records and by asking the patients. Data were also collected from blood, urine and saliva samples to measure biological markers of dehydration, HF severity and stress. Results: Thirst was prevalent in 1 out of 5 patients (II) and 63% of patients with worsening of HF symptoms experienced moderate to severe thirst distress at hospital admission (IV). Patients at an outpatient HF clinic who reported thirst at the first visit were more often thirsty at the follow-up visits compared to patients who did not report thirst at the first visit (II). Thirst intensity was significantly higher in patients hospitalized with decompensated HF compared to patients with no HF (median 75 vs. 25 mm, visual analogue scale [VAS] 0-100 mm; P < 0.001) (I). During optimization of pharmacological treatment of HF, thirst intensity increased in 67% of the patients. Thirst intensity increased significantly more in patients in the high thirst intensity group compared to patients in the low thirst intensity group (median +18 mm vs. -3 mm; P < 0.001) (III). Patients who were admitted to the hospital with high thirst distress continued to have high thirst distress over time (IV). A large number of patients were bothered by thirst and feeling dry in the mouth when they were thirsty (III, IV). Patients with a fluid restriction had high thirst distress over time and patients who were feeling depressed had high thirst intensity over time (IV). Thirst was associated with fluid restriction (III-IV), a higher serum urea (IIIII), and depressive symptoms (II). Conclusions: A considerable amount of patients with HF experiences thirst intensity and thirst distress. Patients who reported thirst at the first follow-up more often had thirst at the subsequent follow-ups. The most important factors related to thirst intensity or thirst distress were a fluid restriction, a higher plasma urea, and depressive symptoms. Nurses should ask patients with HF if they are thirsty and measure the thirst intensity and thirst distress, and ask if thirst is bothering them. Each patient should be critically evaluated if a fluid restriction really is needed, if the patient might be dehydrated or needs to be treated for depression.

The consequences of ingesting different carbohydrate solutions on fluid movement and availability have not been systematically examined. In addition, the role of carbohydrate in the post-exercise rehydration period has received little attention despite the need for substrate replenishment following exercise and the role of carbohydrates in stimulating water absorption in the intestine. The aims of this thesis were to assess fluid absorption characteristics and availability of solutions containing increasing concentrations of glucose and to evaluate their role in the restoration and maintenance of fluid balance following a period of exercise-induced dehydration. The ingestion of a single bolus of a commercially available hypertonic 18% carbohydrate solution (chapter 3) and a hypertonic 10% glucose solution (chapter 4) resulted in reductions in plasma volume that are most likely due to acute net secretion of water into the intestinal lumen. When investigating recovery of whole body hydration status after sweat loss, a hypertonic 10% glucose-electrolyte solution maintained whole body fluid balance for a longer period than a hypotonic 2% glucose-electrolyte solution and an electrolyte only solution when a fixed volume of fluid was consumed during a rehydration period of one hour following cycle exercise in the heat (chapter 5). When fluid was consumed ad libitum over a two hour period following similar cycle exercise in the heat, a hypertonic 10% glucose-electrolyte solution was as effective in restoring and maintaining fluid balance as a 2% hypotonic glucose-electrolyte solution and an electrolyte only solution (chapter 6). The reduced rate of gastric emptying that accompanies the ingestion of high carbohydrate solutions was likely to be the primary cause for the difference in urine production reported between thetrials during this study (chapter 7). In conclusion, ingestion of hypertonic carbohydrate solutions results in a reduction in extracellular fluid volume that is most likely due to secretion of water into the intestinal lumen and the carbohydrate content of an ingested solution is of importance in the post-exercise rehydration period.

L'exercice permet l'acquisition et l'intégration de nouvelles habiletés motrices propres à la nature de l'activité considérée. L'exercice est également un facteur de risque de lésions et semble altérer temporairement la fonction d'équilibration. Cependant, les mécanismes physiologiques et physiopathologiques et leurs conséquences sur la fonction d'équilibration sont encore mal connus. Ce travail, pour lequel le cyclisme a été utilisé comme modèle neurosensoriel, visait à évaluer les éventuelles modifications des stratégies sensori-motrices physiologiques et compensatoires de la fonction d'équilibration en fonction du type d'exercice et de perturbations de l'homéostasie.Les stratégies sensori-motrices de routiers et de vététistes et celles des effets d'une déshydratation induite par un exercice ont été évaluées par posturographie. De plus, la prévalence de vertiges après compétitions ou entraînements a été évaluée par questionnaire chez des routiers et des descendeurs (spécialistes du vélo tout terrain descente). Pour assurer la fonction d'équilibration, les vététistes, qui pratiquaient le plus de VTT, utilisaient principalement les informations proprioceptives. Les routiers et les vététistes, qui pratiquaient le plus le cyclisme sur route, utilisaient davantage les informations visuelles. La déshydratation induite par l'exercice altérait temporairement le contrôle postural. Plus la déshydratation était importante, moins les informations vestibulaires étaient requises. Les vertiges survenaient couramment après la pratique du cyclisme et, en particulier, en VTT descente. L'épuisement a été rapporté comme un déterminant important des vertiges en cyclisme sur route alors que les accélérations-décélérations brusques et les chutes ont été rapportées comme déterminants des vertiges en VTT descente.La différence d'organisation sensorielle entre les vététistes et les routiers peut être expliquée par des processus adaptatifs élaborés à partir des stimulations environnementales et des spécificités techniques de ces disciplines. Bien que la fatigue musculaire puisse expliquer les altérations posturales à la suite d'un exercice, les modifications de l'homéostasie des liquides vestibulaires peuvent également diminuer le poids de l'information vestibulaire dans la régulation de l'équilibration. Les mécanismes physiopathologiques générant des vertiges peuvent être liés à des modifications homéostatiques induites par l'effort en cyclisme sur route. En VTT descente, les accélérations-décélérations (incluant les chutes), auxquelles la tête est soumise, peuvent générer des dysfonctionnements des structures vestibulaires, en particulier des organes otolithiques / Exercise leads to the acquisition and the integration of new motor skills specific for the type of practiced activity. Exercise is also a risk factor for injuries and seems to transiently alter the balance function. Nevertheless, physiological and pathophysiological mechanisms and their consequences on balance function still remain unclear. This work, which used cycling as a neurosensory model, aimed to evaluate the possible changes of physiological and compensatory balance-related sensory-motor strategies in function of the type of exercise and homeostatic perturbations. Road cyclists? (RCs) and mountain bikers? (MTBs) sensory-motor strategies were evaluated by posturography as well as the effects of exercise-related dehydration. Moreover, the prevalence of vertigo after competitions or training sessions was investigated by a questionnaire in RCs and downhill mountain bikers (MTBsDh).Balance-related visual information was better used by RCs and MTBs, who mainly practised road cycling. Somesthetic information was better used in MTB, who mainly practiced mountain biking. Exercise-related dehydration transiently altered postural control. The more severe the dehydration, the lower was the use of vestibular information. Vertigo commonly occurred after the practice of cycling, particularly in downhill mountain biking. Exhaustion was reported as a crucial factor for vertigo by RCs, whereas for MTBs it was sudden accelerations-decelerations and falls.The difference in sensory organisation between MTB and RC could be explained by adaptive processes elaborated from environmental stimulations and technical specificities of these disciplines. Even though muscular fatigue could explain the exercise-induced alterations of postural performances, vestibular fluid modifications may also be involved by their influence on intralabyrinthine homeostasis, lowering thus the contribution of vestibular information on balance control. The pathophysiological mechanisms generating vertigo might be an effort-related disturbance of homeostasis in RCs. In MTBsDh, the accelerations-decelerations (including falls), to which the head is subjected, might generate dysfunction of peripheral vestibular structures, particularly the otolith organs

Doctor of Philosophy / Department of Chemical Engineering / Keith L. Hohn / Extensive research has gone into developing and modeling the three-way catalyst (TWC) to reduce the emissions of hydrocarbons, NOx and CO from gasoline-fueled engines level. However, much less has been done to model the use of the three-way catalyst to treat exhaust from natural gas-fueled engines. Our research address this gap in the literature by developing a detailed surface reaction mechanism for platinum based on elementary-step reactions. A reaction mechanism consisting of 24 species and 115 elementary reactions was constructed from literature values. All reaction parameters were used as found in the literature sources except for steps modified to improve the model fit to the experimental data. The TWC was simulated as a one-dimension, isothermal plug flow reactor (PFR) for the steady state condition and a continuous stirred-tank reactor (CSTR) for the dithering condition. This work describes a method to quantitatively simulate the natural gas engine TWC converter performance, providing a deep understanding of the surface chemistry in the converter. Due to the depletion of petroleum oil and recent volatility in price, synthesizing value-added chemicals from biomass-derived materials has attracted extensive attention. 1, 3-butadiene (BD), an important intermediate to produce rubber, is conventionally produced from petroleum. Recently, one potential route is to produce BD by dehydration of 2, 3-butanediol (BDO), which is produced at high yield from biomass. This reaction was studied over two commercial forms of alumina. Our results indicate acid/base properties greatly impact the BD selectivity. Trimethylamine can also modify the acid/base properties on alumina surface and affect the BD selectivity. Scandium oxide, acidic oxide or zirconia dual bed systems are also studied and our results show that acidic oxide used as the second bed catalyst can promote the formation of BD, while 2,5-dimethylphenol is found when the zirconia is used as the second bed catalyst which is due to the strong basic sites.

A Thesis Submitted to the Faculty of Education, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master in Education / This study aimed to assess selected physiological, osmoregulatory and thermoregulatory responses to tennis play in children, Twenty-four young male tennis players (X age; 13.3+ 1.31 years) were stndied while playing for 90 min under warm environmental conditions (WBGT index= 13-19). Ad libitum consumption of pure water was permitted. Questionnaires were used in order to elicit information regarding the health status, degree of aeelimatizationnnd pre-match trait and state anxiety of the subjects. The physiological variables assessed. included pre- and post-match rectal temperature (T), heart rate (HR) and oxygen consumption (02) during the match. The biochemical observations included pre- and postmatch blood glucose, haematoerit (Ret), haemoglobin (lIb), plasma electrolyte (Na", Cl', K+, Mg++) and total plasma protein (TPP) concentrations. The findings )q~ed that the young tennis players investigated in this study experienced, ~de!'ate levels of pre-competitive trait and state amdety. The estimated nie.m exercise intensity of 50-55% of VOzmax for a duration of 90 min resulted. in a Tre increase of 0.73 •C. Mean percentage dehydration was 0.MO+O.25. Plasma volume (PV) changes were insignificant and were positively related to TPP changes. Mean plasma. Na" and CI- concentrations increased by 0.88 mmol.r" and 2.2 mmol.r:' respectively. The subjects' mean H... response (145 bpm) of a subset or the sample(n=13) and estimated VOz (21.38 ml.kg-l.min-~ represented a 55% of the age adjusted HRmax reserve and approximately a 50-55% of V02 max respectively. The time spent within the target heart rate range (60-85% HR. max reserve) comprised only 33% of the match duration. Mean energy expenditure was estimated to be 1772 KJ dUl'ing the 90 min period. Itwas calculated that in order to prevent harmful levels of dehydration under warm environmental conditions and at an exercise intensity of tennis play of approximately 55% of the age adjusted HR max reserve or 50-55% of V02 max, consumption of 4.44-6.81 mI.Kg-1.br-1 or 200-360 ml.hr" of water is recommended in young tennis players possessing a body mass of 45-53 Kg. The precise quantity was concluded to be a function of the mass and exercise intensity of the subjects and the environmental heat stress index during play. / Andrew Chakane 2018

Håldäcksbjälklag är ett fördelaktigt bjälklagsalternativ på grund av dess många fördelar så som reducerad vikt och snabbt montage. Däremot har bland annat korta byggtider medfört att betongblandningar med lågt vct och hög andel cement efterfrågats av Strängbetongs kunder för att reducera risken för fuktproblematik, då en snabb uttorkning eftersträvas. Med en allt strängare och ambitiösare miljömålsättning har ett behov för att reducera andelen cement uppkommit. Vid en minskad cementmängd ökar således betongens vct vilket leder till en miljövänligare framställning samtidigt som en ekonomisk vinning erhålls. Syftet med undersökningen är därför att undersöka om olika betongblandningar med ett högre vct kan ersätta den nuvarande betongblandningen och samtidigt uppfylla förekommande uttorkningskrav. Detta skulle innebära fördelar för såväl producenterna som för beställarna. Betongen som undersökts i utredningen är av jordfuktig karaktär och är enbart avsedd för håldäckstillverkning. Uttorkningsprocessen som studeras motsvarar uttorkningen från tillverkning fram till montage. Fyra olika betongblandningar fördelade på tolv kuber kommer att undersökas i tre olika klimat och enbart uttorkningsmässiga skillnader mellan kuberna kommer att jämföras. Undersökningen baseras på mätdata som grundar på mätningar utförda av en auktoriserad fuktkonsult via Rådet för byggkompetens, RBK. Betongrecepten i utredningen har framtagits av Cementa. Litteraturstudier används även för att styrka påståenden och underlag som framkommer i rapporten. Resultatet från studien visar att de kuber som förvarats i inomhusklimatet och i klimatrummet har en linjär uttorkningsutveckling, till skillnad från kuberna som är placerade i utomhusklimatet som har en olinjär uttorkningsutveckling. I inomhusklimatet och i klimatrummet har kuberna med högre vct torkat ut mer än betongblandningarna med lägre vct (0,40 och 0,45), däremot är skillnaden i uttorkning minimal i kuberna som har förvarats utomhus. Den fastställda slutsatsen i undersökningen är att mer djupgående och längre mätstudier behövs för att säkerställa hur betonguttorkningen förändras i ett senare skede av uttorkningsprocessen. / Hollow-deck joists are an advantageous flooring alternative because of its many advantages such as reduced weight and rapid assembly. However, among other things, short construction times have meant that concrete mixes with low w/c ratio and high proportion of cement have been requested by Strängbetongs customers in order to reduce the risk of moisture problems, when a rapid drying out pursued. With an increasingly stringent and ambitious environmental goal, a need to reduce the proportion of cement has arisen. With a reduced amount of cement, the w/c ratio of the concrete increases, which leads to a more environmentally friendly production, while at the same time an economic gain is obtained. The purpose of the study is therefore to investigate whether different concrete mixes with a higher w/c ratio can replace the current concrete mix and at the same time meet existing drying requirements. This would mean benefits for both the producers and orderers. The concrete that has been investigated in the investigation is of a soil-moist nature and is only intended for hole-deck production. The drying process that is studied corresponds to the dehydration from production to assembly. Four different concrete mixes divided into twelve cubes will be investigated in three different climates and only dehydration differences between the cubes will be compared. The survey is based on measurement data that are based on measurements performed by an authorized moisture consultant at Rådet för byggkompetens, RBK. The concrete recipes in the investigation have been developed by Cementa. Literature studies are also used to substantiate claims and supporting documents that appear in the report. The results from the study show that the cubes stored in the indoor climate and in the climate room have a linear dehydration development, unlike the cubes located in the outdoor climate that has a nonlinear dehydration development. In the indoor climate and in the climate room, the cubes with higher w/c ratio have dried out more than the concrete mixtures with lower w/c ratio (0,40 and 0,45), however, the difference in dehydration is minimal in the cubes that have been stored outdoors. The established conclusion in the study is that more in-depth and longer measurement studies are needed to ensure how concrete dehydration changes at a later stage of the drying process.

Os finos de resíduos cimentícios (previamente hidratados) podem ser reciclados através de tratamento térmico, tornando-se um ligante alternativo. Quando tratados termicamente em temperaturas inferiores a 550ºC, o processo não gera emissões de CO2 relativas à descarbonatação do calcário. Esta pesquisa teve como objetivo reativar o cimento Portland de alto forno (CP III) previamente hidratado, desidratando-o em temperatura de 500°C com patamar de 2h e reidratando-o com teores de água e de dispersante variados. Inicialmente foram realizadas caracterizações a fim de comparar as características físico-químicas do cimento desidratado com o cimento anidro. Posteriormente, foram analisadas as transformações de fases observadas com a hidratação, desidratação e reidratação do cimento. A segunda parte do estudo foi de otimização das pastas reidratadas e hidratadas, onde foram definidas condições ideais de dispersão, com a saturação ideal de dispersantes e teores mínimos de água resultado em pastas com volume de poros menores e consequentemente resistências mais elevadas. Os resultados obtidos comprovaram que o cimento desidratado se reidrata e forma fases similares às fases formadas na hidratação, como C-S-H, portlandita, hidrotalcita, etc. O cimento de alto forno carbonata mais do que o cimento Portland (CP V). Devido à área superficial elevada (14 vezes superior ao do cimento anidro), o cimento desidratado libera calor de molhagem elevado, consequencia da recombinação da água com as fases desidratadas. Observou-se ainda que, é possível controlar a resistência à compressão da pasta reidratada, otimizando o volume de poros presentes nas pastas. As resistências das pastas reidratadas com dispersante aos 28 dias foram 2,37 vezes maiores quando comparados com sistemas aglomerados. Com relação a porosidade, há indícios que é possível obter níveis de porosidade para as pastas reidratadas semelhantes com a pasta hidratada. / The fines of cementitious wastes (previously hydrated) can be recycled through heat treatment, becoming an alternative binder. When heat treated at temperatures below 550°C, the process does not generate CO2 emissions relative to limestone decarbonation. The objective of this research was to reactivate the previously hydrated Portland cement (CP III), dehydrating it at a temperature of 500°C with a 2-hours plateau and rehydrating it with varying water and dispersant contents. Characterization was initially performed to compare the physicochemical characteristics of dehydrated cement (DC) with anhydrous cement (AC). Subsequently, the AC-HP phase transformations for DC-RP were analyzed. The second part of the study was the optimization of rehydrated (RP) and hydrated (HP) pastes, where ideal dispersion conditions were defined, with optimum dispersant and water minimum contents, resulting in pastes with smaller pore volumes and consequently more compressive strength high. The results confirm that the DC rehydrates and forms phases similar to the phases formed in the hydration, such as C-S-H, portlandite, hydrotalcite, etc. The blast furnace cement carbonate more than Portland cement (no additions). Due to the high surface area (14 times higher than that of the AC), the DC releases high wetting heat, due to the recombination of the water with the dehydrated phases. It was also observed that it is possible to control the compressive strength of the rehydrated paste by optimizing the pore volume present in the pastes. The strengths of dispersed pastes with additives at 28 days were 2.37 times higher when compared to agglomerated systems. With respect to porosity, there are indications that it is possible to obtain porosity levels for the similar rehydrated pastes with the hydrated paste.