Microbial-Induced Calcium Carbonate (CaCO3) Precipitation (MICP) is a biological process in which microbial activities alter the surrounding aqueous environment and induce CaCO3 precipitation. Because the formed CaCO3 crystals can bond soil particles and improve the mechanical properties of soils such as strength, MICP has been explored for potential engineering applications such as soil stabilisation. However, it has been difficult to control and predict the properties of CaCO3 precipitates, thus making it very challenging to achieve homogeneous MICP-treated soils with the desired mechanical properties. This PhD study investigates MICP at both micro and macro scales to improve the micro-scale understandings of MICP which can be applied at the macro-scale for improving the homogeneity and mechanical properties of MICP-treated sand. A microfluidic chip which models a sandy soil matrix was designed and fabricated to investigate the micro-scale fundamentals of MICP. The first important finding was that, during MICP processes, phase transformation of CaCO3 can occur, which results in smaller and less stable CaCO3 crystals dissolving at the expense of growth of larger and more stable CaCO3 crystals. In addition, it was found that bacteria can aggregate after being mixed with cementation solution, and both bacterial density and the concentration of cementation solution affect the size of aggregates, which may consequently affect the transport and distribution of bacteria in a soil matrix. Furthermore, bacterial density was found to have a profound effect on both the growth kinetics and characteristics of CaCO3. A higher bacterial density resulted in a quicker formation of a larger amount of smaller crystals, whereas a lower bacterial density resulted in a slower formation of fewer but larger crystals. Based on the findings from micro-scale experiments, upscaling experiments were conducted on sandy soils to investigate the effect of injection interval on the strength of MICP treated soils and the effects of bacterial density and concentration of cementation solution on the uniformity of MICP treated soils. Increasing the interval between injections of cementation solution (from 4 h to 24 h) increased the average size of CaCO3 crystals and the resulting strength of MICP-treated sand. An optimised combination of bacterial density and cementation solution concentration resulted in a relative homogeneous distribution of CaCO3 content and suitable strength and stiffness of MICP-treated sand. This thesis study revealed that a microfluidic chip is a very useful tool to investigate the micro-scale fundamentals of MICP including the behaviour of bacteria and the process of CaCO3 precipitation. The optimised MICP protocols will be useful for improving the engineering performance of MICP-treated sandy soils such as uniformity and strength.

L’objectif de ce travail est d’adapter une formulation dispersante mise au point par la société Mäder à la dispersion de carbonate de calcium (CaCO3) dans une résine polyester insaturée (UP). Le carbonate de calcium est utilisé en tant que charge dans les matériaux composites à matrice thermodurcissable et en particulier dans les SMC (Sheet Molding Compound). Le rôle de cette formulation est de diminuer les viscosités de résines UP fortement chargées tout en conservant voire en améliorant les propriétés mécaniques des composites formés par un renforcement de l’interface charge / matrice. Trois grands axes ont été développés au cours de ce travail : - le comportement rhéologique d’un mélange CaCO3/résine UP a été déterminé et la formulation dispersante a été optimisée ; - la nature des interactions entre les différents constituants de la formulation dispersante et la surface du CaCO3 a été mise en évidence ; - de nouveaux polymères permettant une dispersion plus efficace de la charge dans la résine ont été synthétisés. Le mélange CaCO3 / résine UP présente un comportement rhéologique complexe. L’optimisation de la formulation dispersante a permis d’augmenter de plusieurs pourcents le taux de charge tout en conservant des viscosités inférieures à celle autorisée par le procédé industriel. L’étude des interactions des constituants de la formulation avec le carbonate de calcium a permis de déterminer les fonctions les plus réactives et de comprendre leur interaction avec la surface de la charge. La synthèse de nouveaux dispersants a également été effectuée. Ces derniers ont ensuite été testés dans l’application et ont montré une efficacité à disperser le CaCO3 dans la résine UP. / The aim of this study is to adapt a dispersive formulation developed by the Mäder group to the dispersion of calcium carbonate (CaCO3) in an unsaturated polyester resin (UP). The CaCO3 is commonly used as filler in the domain of composites especially for Sheet Molding Compound (SMC). This dispersive formulation is able to decrease the viscosity of UP resin containing a high amount of filler. In addition, the mechanical properties of composites could be increased by reinforcing the filler / matrix interface. Three main ways have been studied: - characterization of the rheological behavior of CaCO3 / polyester blends and optimization of the dispersive formulation ; - determination of the interactions between the dispersive formulation components and the CaCO3 surface ; - synthesis of new polymers in order to improve the CaCO3 dispersion in an organic matrix. A complex rheological behavior has been observed for CaCO3 / polyester blends. The dispersive formulation improvement led to an increasing of the filler percentage by keeping the viscosity under the industrial limit. The most reactive functions with the CaCO3 surface have been identified by studying the interactions between the dispersive formulation components and the CaCO3 surface. New dispersing agents have been synthesized. Their efficiency has been demonstrated for the dispersion of CaCO3 in a UP resin.

O hexaluminato de cálcio (CaAl12O19 ou CA6) poroso é um material promissor para aplicações de isolamento térmico pois combina baixa condutividade térmica (~0,33 Wm-1K-1 a 1400 °C), resistência mecânica razoável (2 – 8 MPa), inércia química, boa refratariedade (Tf ~1830 °C) e alta resistência ao choque térmico. Existem várias rotas para se obter o CA6 por meio de reações em temperaturas acima de 1300 °C, usando diversas fontes de Al2O3 e CaO, assim como diferentes métodos de processamento. No entanto, embora suas propriedades físicas tenham sido avaliadas, dois pontos principais ainda requerem investigação: o impacto das características das matérias-primas no desenvolvimento da microestrutura de sistemas porosos formados in situ, e a evolução da microestrutura e propriedades de sistemas obtidos a partir de CA6 pré-formado. Neste trabalho, foram produzidas peças de CA6 in situ a partir de diferentes fontes de Al2O3 (alumina calcinada e hidróxido de alumínio) e carbonato de cálcio (CaCO3) de diferentes granulometrias, processados por prensagem uniaxial e moldagem direta de suspensões e submetidas a diferentes tratamentos térmicos. As amostras (verdes e secas e após tratamento térmico) foram submetidas à análise microestrutural (MEV e DRX) e dilatométrica, ensaios para determinação das propriedades físicas (porosidade total, distribuição de tamanho de poros e condutividade térmica) e propriedades mecânicas (resistência à ruptura por compressão e módulo elástico). Estruturas à base de CA6 formado in situ obtidas por prensagem e moldagem direta apresentaram elevada porosidade (até 71 %) e uma resistência à compressão acima de 10 MPa. Verificou-se que o processo de conformação determinou a porosidade à verde inicial da peça, enquanto o tamanho de partícula de alumina induziu a um crescimento de grão assimétrico (partícula grossa) ou à densificação da peça (partícula fina). Dois mecanismos antagonistas acontecem ao mesmo tempo na reação in situ: a reação expansiva da formação de aluminatos intermediários (efeito porogênico) e a densificação das partículas de Al2O3. As partículas de carbonato tiveram uma grande influência no tamanho final dos poros. O efeito porogênico do hidróxido de alumínio foi efetivo até um conteúdo máximo de 50 %vol. / Porous calcium hexaluminate (CaAl12O19 or CA6) is a promising material for thermal insulation applications because it combines low thermal conductivity (~0,33 Wm-1K-1 at 1400° C), reasonable mechanical strength (2 – 8 MPa), chemical inertia, good refractoriness (Tf ~1830 °C) and high resistance to thermal shock. There are several routes to obtain CA6 by reactions at temperatures above 1300 °C, using various sources of Al2O3 and CaO, as well as different processing methods. However, although its physical properties have been studied, two main points still require investigation: the impact of the characteristics of the raw materials on the development of the microstructure of in situ formed porous systems, and the evolution of the microstructure and properties of systems obtained from preformed CA6. In this study, in situ CA6 bodies were produced from different sources of Al2O3 (calcined alumina and aluminum hydroxide) and calcium carbonate (CaCO3) of different granulometries, processed by uniaxial pressing and direct molding of suspensions and thermally treated at different temperatures. The samples (green and heat treated ones) were submitted to microstructural analysis (SEM and XRD) and dilatometry, also tests to determine the physical properties (total porosity, Hg porosimetry and thermal conductivity) and mechanical properties (compression strength and elastic modulus). In situ formed CA6-based structures obtained by pressing and direct molding showed high porosity (up to 71%) and a compressive strength above 10 MPa. It was found that the conformation process determined the initial porosity of the green body, while particle size of alumina may induce asymmetric grain growth (coarse particle) or densification of the ceramic body (fine particle). Two antagonistic mechanisms occur at the same time in the in situ reaction: the expansive reaction of the formation of intermediate aluminates (porogenic effect) and the densification of Al2O3 particles. The carbonate particles had a great influence on the final pore size. The porogenic effect of aluminum hydroxide was effective up to a maximum content of 50% vol.

Specially designed non-damaging lost circulation pills (LCP) are being effectively applied for drilling depleted zones worldwide. Optimizing the LCP compositions stop the lost circulation effectively and protect the production zone from liquid and solids invasion significantly. Shape, particle size distribution and concentration of the lost circulation materials (LCM) are key parameters determining the effectiveness of LCP. In this study, the Permeability Plugging Apparatus (PPA) is utilized to evaluate effectiveness of various LCM&rsquo / s in curing the lost circulation. Sized calcium carbonates are used as LCM in different concentrations and in different particle size distribution. Lost circulation zones are simulated using the ceramic disks and slotted disks. Ceramic disks with nominal pore sizes 20, 35, 60, 90, and 150 microns are characterized in terms of pore size distribution using the computerized image analysis technique. Filter cake quality, spurt loss and filtrate volume are basic parameters to be evaluated in this study. Tests are performed at 75 F and 300 psi of differential.

Στο πλαίσιο της παρούσας εργασίας έγινε προσπάθεια για την ανάπτυξη αναλυτικών μεθοδολογιών με στόχο την ταυτοποίηση και την ποσοτική ανάλυση σε περιπτώσεις ταυτόχρονης συνύπαρξης και των τριών φάσεων του άνυδρου κρυσταλλικού ανθρακικού ασβεστίου. Η Φασματοσκοπία Raman και η Φασματοσκοπία Υπερύθρου ήταν οι δύο αναλυτικές τεχνικές οι οποίες χρησιμοποιήθηκαν σαν βάση για την ανάπτυξη των ανάλογων αναλυτικών μεθοδολογιών. Η χρήση της Φασματοσκοπίας Raman οδήγησε στην ανάπτυξη μιας μη καταστροφικής αναλυτικής μεθοδολογίας, στην οποία όμως μόνο τα σχετικά ποσοστά των τριών φάσεων έγινε δυνατόν να προσδιοριστούν. Για την δημιουργία των ευθειών αναφοράς, κατασκευάστηκαν δυαδικά μίγματα, ενώ χρησιμοποιήθηκαν οι κορυφές στα 711cm-1 για τον ασβεστίτη, στα 700cm-1 για τον αραγωνίτη και στα 750cm-1 για τον βατερίτη. Τα όρια ανίχνευσης προσδιορίστηκαν 0.13mol%, 0.18mol% και 1.3mol% για τον ασβεστίτη, αραγωνίτη και βατερίτη αντίστοιχα, ενώ τα σφάλματα κατά τον προσδιορισμό τριαδικού μίγματος γνωστής σύστασης βρέθησαν να είναι 1.6mol% για τον ασβεστίτη, 0.3mol% για τον αραγωνίτη και 1.1mol% για τον βατερίτη. Στην προσπάθεια επιλογής των κατάλληλων δονήσεων Raman, έγινε μελέτη των φασμάτων Raman των καθαρών κρυσταλλικών φάσεων και απόδοση των κορυφών. Τέλος με την χρήση της Φασματοσκοπίας IR έγινε δυνατός ο προσδιορισμός των απόλυτων ποσοστών των τριών φάσεων, κάνοντας χρήση των δονήσεων στα 714cm-1 για τον ασβεστίτη, στα 700cm-1 και 714cm-1 για τον αραγωνίτη και στα 745cm-1 για τον βατερίτη. Οι απόρροφητικότητες των κορυφών (σε mg-1CaCO3 mm-2) βρέθηκαν ίσες με: α 63.38 714 = για τον ασβεστίτη, α .30 700 = 19 και α .43 714 = 40 για τον αραγωνίτη και α .79 745 = 21 για τον βατερίτη. Τα όρια ανίχνευσης (σε mgCaCO3/mm2) προσδιορίστηκαν σε: 714 -4 C O.A. =6.6 ×10 για τον ασβεστίτη, 700 -3 A O.A. =2.2 ×10 και 714 -3 A O.A. =1.1×10 για τον αραγωνίτη και 745 -3 V O.A. =1.9 ×10 για τον βατερίτη. / In the present work new analytical methodologies were developed for the study of calcium carbonate polymorphs (calcite, aragonite, vaterite). Two vibrational techniques were employed for the simultaneous quantitative analysis of mixtures of crystalline materials; Raman Spectroscopy (non-destructive technique), Infrared Spectroscopy (destructive technique). Using binary mixtures from known quantities of the crystal phase the calibration curves were constructed using the Raman bands at 711cm-1 for calcite, 700cm-1 for aragonite and 750cm-1 for vaterite. Detection limits (DL) were found to be 0.13, 0.18 and 1.3mol % for calcite, aragonite and vaterite, respectively, while the relative errors in determining the mol % of a known ternary mixture of calcium carbonate polymorphs were 1.6% for calcite, 0.3% for aragonite and 1.1% for vaterite. Infrared Spectroscopy was used, in order to determinate the absolute concentration of the calcium carbonate crystal phases, using the bands at 714cm-1 for calcite, at 700cm- 1 and 714cm-1 for aragonite and at 745cm-1 for vaterite. The asborptivities were found to be α 63.38 714 = for calcite, α .30 700 = 19 and α .43 714 = 40 for aragonite and α .79 745 = 21 for vaterite. The detection limits were also established and found to be 714 -4 C D.L. = 6.6 ×10 for calcite, 700 -3 A D.L. = 2.2 ×10 and 714 -3 A D.L. =1.1×10 for aragonite and 745 -3 V D.L. = 1.9 ×10 for vaterite.

The main purpose of this thesis was to find ways to maintain a low level of light‐induceddiscolouration at an increased addition of mechanical and chemimechanical pulps in coated highqualityfine paper and magazine paper grades. Current technology allows the production of highyieldpulps such as thermomechanical and chemimechanical pulps with properties suitable formanufacturing high‐quality paper or paperboard with a low basis weight. Coating of woodcontainingpaper will probably be necessary for photo‐stability reasons if lignin‐containing pulps areto be used as the main fibre furnish in long‐life and high‐value products.In order to find the most suitable pulp for this purpose, light‐induced discolouration of a variety ofpaper samples from unbleached and bleached softwood and hardwood pulps was studied under bothaccelerated and long‐term ambient light‐induced ageing conditions. Hardwood high‐yield pulps,especially aspen pulps, were proven to be more photo‐stable compared to softwood pulps. Hardwoodpulps should therefore be the first choice for applications where a high permanence is desirable.Evaluating ageing characteristics using the CIELAB colour system showed that accelerated ageingconditions tend to mainly increase the b* value and decrease the L* value (i.e. yellow the pulp),whereas long‐term ambient ageing also increases the a* value, which makes the pulp more reddish.A new method for studying the influence of the UV‐screening properties of coating layers on abase paper was developed, and used to investigate the effect of pigment, pigment size distribution,binder and UV‐absorbing additives. The coat weight and pigment type were found to be the mostimportant factors for reducing the transmittance of UV‐radiation. Coating colours containing kaolinpigments had a lower UV‐transmittance than calcium carbonate pigments. Of the calcium carbonates,precipitated calcium carbonates were better than ground calcium carbonates and the difference wasgreater at higher coat weights. The particle size distribution should preferable be narrow. When thebest pigment (bleached kaolin) and the best binder (styrene butadiene latex) were combined withtitanium dioxide, the UV‐transmittance could be reduced by about 90% at a coat weight of ~10 g/m2.At a coat weight close to 20 g/m2, the transmittance was close to zero. This shows that it is possible tomore or less fully protect a double coated base paper from harmful UV‐radiation, when the coatinglayer has an optimum composition for that purpose. A prerequisite to reach so far is that the coatinglayer has an even coat weight.

L'implantation de matériaux pour reconstruction osseuse par des techniques chirurgicales peu invasives nécessite des substituts osseux synthétiques, résorbables, injectables et radioopaques. C'est pourquoi le contrôle des propriétés de ces matériaux est primordial. Dans ce contexte, ce travail s'intéresse à la formulation de deux ciments, l'un uniquement à base de carbonate de calcium, le second composé d'un mélange de carbonate de calcium et de phosphate de calcium en quantités égales. Le traitement des phases solides pulvérulentes de ces deux ciments par les procédés de broyage et de co-broyage a été étudié. Ces procédés permettent entre autres de diminuer la taille moyenne des particules. Un mélange intime et homogène entre les constituants de la phase solide est obtenu grâce au co-broyage et les propriétés des ciments sont très significativement améliorées. Le temps de prise est diminué et l'injectabilité de la pâte est fortement augmentée (facteur 100). Cette dernière propriété a pu être évaluée grâce à la mise au point d'un dispositif et d'un protocole de mesure adaptés à un analyseur de texture. Dans le but de visualiser par radiographie aux rayons X l'introduction du ciment injectable dans le site osseux à réparer, du strontium a été introduit en tant qu'agent de contraste radio-opacifiant. Deux voies d'ajout à la formulation du ciment ont été étudiées : la première sous forme de SrCO3 dans la phase solide, la seconde sous forme de SrCl2 dans la phase liquide. Les études réalisées montrent que le co-broyage de la phase solide contenant du SrCO3 est intéressant pour homogénéiser la dispersion de l'agent de contraste et ainsi optimiser la quantité de strontium à incorporer pour atteindre le niveau de radio-opacité requis par la norme en vigueur. De plus, il a été observé que l'ajout de SrCl2 dans la phase liquide rend la pâte plus visqueuse et diminue son injectabilité. Par ailleurs, l'étude de la dissolution de ces ciments à pH physiologique a révélé une libération lente et prolongée du strontium. Enfin, des tests cellulaires in-vitro ont été réalisés sur ces ciments ; ils mettent en évidence l'excellent comportement de cellules ostéoprogénitrices vis-à-vis de ces formulations de ciment ainsi que l'intérêt d'utiliser le sel de SrCO3 plutôt que de SrCl2. La dernière partie de ce travail concerne l'étude de la cristallisation de l'aragonite, variété polymorphe du carbonate de calcium, en présence d'ions phosphate, connus pour inhiber la cristallisation du CaCO3. Grâce à une modélisation à l'aide de la technique de croissance cristalline à composition constante permettant de se placer dans des conditions proches de celles de la prise du ciment uniquement à base de carbonate de calcium in-vivo, il a été montré que la présence d'ions phosphate, même en très faible quantité (concentration < 0,5 µM) diminue à la fois la vitesse de germination et la vitesse de croissance cristalline de l'aragonite. L'ensemble de ces travaux contribue à l'optimisation des propriétés de ces ciments biomédicaux et à mieux appréhender leur comportement que ce soit au moment de leur implantation in-vivo ou de leur évolution et suivi post-opératoires. D'un point de vue fondamental, ces travaux pluridisciplinaires menés dans des conditions modèles in-vitro mais également dans le cadre d'une expérimentation in-vivo ont mis en évidence l'intérêt de confronter ces deux approches pour identifier et comprendre les phénomènes et les réactions impliqués lors de la prise des ciments à base de carbonate de calcium in-vitro et in-vivo. / Implantation of bone substitute materials using minimally invasive surgical techniques requires specific properties for the material including resorbability, injectability and adequate radio-opacity. The control of such properties of the material is of prime importance to meet a surgeon's requirements. In this context, this study deals with two different mineral cements: the first one is only composed of calcium carbonate phases and the second one is a mixture of equal amount of calcium phosphate and calcium carbonate phases. An original methodology involving complementary analytical techniques was implemented to thoroughly investigate the grinding mechanism of separated or mixed reactive powders constituting the solid phase and its effects on cement reactivity and properties. We show that co-grinding the solid phase decreases the mean size of the particles and favours both a homogeneous mixing and good contact between the components, leading to a decrease in the setting time. We also set two original protocols designed to evaluate paste injectability and phase separation during paste extrusion. Co-grinding leads to synergistic positive effects on cement injectability and radio-opacity. It allows maintaining a low and constant load during the extrusion of paste, which composition remains constant. Moreover, the cement's mechanical properties can be enhanced by lowering the L/S ratio because of the lower plastic limit. To be able to follow in situ the injection of the bone cement using X-ray radiography, strontium has been introduced as a contrast agent in the cement composition. Two different routes have been investigated: SrCO3 has been added to the solid phase or SrCl2 has been dissolved in the liquid phase. We show that co-grinding process permits to homogenise strontium distribution in the cement allowing us to optimise the minimum amount of strontium to add into the cement paste to reach the radio-opacity required by ISO 9917-1 standard. Moreover, adding SrCl2 in the liquid phase makes the cement paste more viscous and diminishes its injectability. Release tests performed on Sr-loaded cements show a sustained release of strontium at 37°C and pH 7.4. Finally, in-vitro cell tests have shown the excellent behaviour of osteoprogenitor cells, especially on cements including SrCO3. The last part of this work deals with the study of the crystallization of aragonite CaCO3 in the presence of phosphate ions, naturally present in biological fluids, to better understand the setting ability of calcium carbonate cements in-vivo. Using the constant composition crystal growth technique, we show that the presence of phosphate ions, even in very low amount (concentration < 0.5 µM) diminishes both the nucleation and the crystal growth rates of aragonite. This work contributes to the optimization of the properties of calcium carbonate-based cements and a better understanding and control of their behaviours during implantation and their evolution in-vivo. From a fundamental point of view, this multidisciplinary work performed in model conditions in-vitro and completed by preliminary in-vivo experiments have underlined the interest in combining these two approaches to identify and understand the phenomena and the chemical reactions involved during the setting of biomedical cements.

Scaling in green liquor handling systems is a persistent problem in many kraft mills. Scaling is commonly believed to be the result of pirssonite (Na2Ca(CO3)2∙2H2O) deposition. In this work, scale characterization was performed by analyzing 12 scale samples obtained from 10 kraft mills. Only 4 samples were identified as pirssonite while the remaining consisted of CaCO3. The predominant presence of CaCO3 in the scale samples was found to be the result of selective dissolution of Na2CO3 from pirssonite scale, leaving CaCO3 behind. Experimental studies were also conducted to study pirssonite solubility under green liquor conditions. Results obtained from these studies were used to create and validate a database for pirssonite in the OLI Systems® software to predict its formation. This database was used to generate a family of pirssonite solubility curves that can be used by the kraft mills as operational guidelines to prevent pirssonite precipitation.

Scaling in green liquor handling systems is a persistent problem in many kraft mills. Scaling is commonly believed to be the result of pirssonite (Na2Ca(CO3)2∙2H2O) deposition. In this work, scale characterization was performed by analyzing 12 scale samples obtained from 10 kraft mills. Only 4 samples were identified as pirssonite while the remaining consisted of CaCO3. The predominant presence of CaCO3 in the scale samples was found to be the result of selective dissolution of Na2CO3 from pirssonite scale, leaving CaCO3 behind. Experimental studies were also conducted to study pirssonite solubility under green liquor conditions. Results obtained from these studies were used to create and validate a database for pirssonite in the OLI Systems® software to predict its formation. This database was used to generate a family of pirssonite solubility curves that can be used by the kraft mills as operational guidelines to prevent pirssonite precipitation.

Made available in DSpace on 2015-04-17T14:49:38Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2333945 bytes, checksum: 37aa07213864fdd3567bdd8aedc1db21 (MD5) Previous issue date: 2014-03-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to evaluate the fortification of white pan bread with whey powder and calcium carbonate and the effects of the addition of these ingredients on the physicochemical and sensory characteristics of the products obtained. A cross-sectional study with adult women (n = 50) was also conducted, in order to assess the dietary intake of calcium and verify its relationship with bone mineral density. The ingredients added to the white pan bread were tested individually and combined, according to a 22 full factorial design, resulting in seven assays. The parameters pH, acidity, specific volume, moisture content, water activity and calcium content were evaluated. Additionally, a consumer acceptance testing was carried for the sensory attributes appearance of the slice and loaf bread, color, flavor, taste and crumb softness, beyond of the overall acceptability on a 9-point hedonic scale. The habitual dietary calcium intake and the consumption of food groups and sources of calcium were evaluated through three 24-hour recalls and food frequency questionnaire, respectively. The bone mineral density of the spine and femur was determined by dual energy absorptiometry X-ray. The method of the apparent adequacy evaluated individual needs of calcium intake and the chi-square test verified associations between bone mineral density and age and calcium intake. The addition of calcium carbonate, in isolated form, promoted an increase in pH and a reduction in the acidity to the final product (assay 3), while the addition individualy of whey powder caused a decrease in the moisture content and water activity in bread of the assay 2. When these two ingredients were combined in the maximum concentration, a reduction in the specific volume of bread (assay 4) was observed. Both calcium carbonate and whey powder increased the calcium content, which ranged from 31.9 mg to 723.3 mg/100g bread. Concerning to the sensory analysis, all the formulations tested were accepted with scores ranging from 6.72 to 8.07. However the bread added with calcium carbonate alone showed a lower acceptance, indicating that the association of this ingredient with whey powder was better accepted. The mean dietary calcium intake was 854.89 ± 697.30 mg/day, lower than recommended for the group >50 years of age and the percentage of apparent adequacy was < 50%, within of the age group and income studied. The consumption daily of the milk and dairy products was an average 1.35 servings. The calcium/protein and calcium/phosphorus ratios were 7,7:1 and 1:1.3, respectively. The presence of osteopenia or osteoporosis was found in 60% of participants, and was associated statistically with age. The results suggest that the fortification of the white pan bread with calcium can be an alternative to increase the calcium intake for adult women over a lifetime. / O objetivo desse trabalho foi avaliar a fortificação de pão de forma com soro de leite em pó e carbonato de cálcio e os efeitos da adição desses ingredientes sobre as características físico-químicas e sensoriais dos produtos obtidos. Ainda, foi realizado um estudo transversal com mulheres adultas (n=50) a fim de avaliar a ingestão dietética de cálcio e verificar a sua relação com a densidade mineral óssea. Os ingredientes adicionados ao pão de forma foram testados individualmente e combinados, segundo um delineamento fatorial completo do tipo 22, totalizando sete ensaios. Os parâmetros avaliados foram pH, acidez, volume específico, teor de umidade, atividade de água e conteúdo de cálcio. Posteriormente, foi aplicado um teste de aceitação sensorial para avaliar a aparência do pão inteiro, aparência da fatia, cor da casca, cor do miolo, aroma, sabor, umidade, maciez do miolo e aceitação global, utilizando escala hedônica de nove pontos. A ingestão habitual de cálcio e o consumo de alimentos fontes desse nutriente foram avaliados por meio de três recordatórios de 24 horas e questionário de freqüência de consumo alimentar, respectivamente. A densidade mineral óssea da coluna e do fêmur foi determinada por absorciometria de energia dupla de raios X. O método da adequação aparente avaliou as necessidades individuais de ingestão de cálcio e o teste qui-quadrado verificou as associações entre a densidade mineral óssea com a idade e com o consumo de cálcio. A adição do carbonato de cálcio, de forma isolada, promoveu elevação no pH e redução na acidez do produto final (ensaio 3), enquanto a adição individual do soro de leite em pó promoveu redução no teor de umidade e atividade de água no pão do ensaio 2. Quando esses dois ingredientes foram combinados, em sua máxima concentração, foi verificada redução no volume específico do pão (ensaio 4). Ambos elevaram o teor de cálcio, que variou de 31,9 mg a 723,3 mg/100g pão. Com relação à análise sensorial, todas as formulações testadas foram aceitas, apresentando escores variando de 6,72 a 8,07, entretanto o pão adicionado somente de carbonato de cálcio apresentou menor aceitação, indicando que a associação deste ingrediente com o soro de leite em pó foi melhor aceita. A ingestão dietética de cálcio foi, em média, 854,89 ± 697,30 mg/dia, estando abaixo do recomendado para o grupo >50 anos de idade e o percentual de adequação aparente foi < 50%, dentro das faixas de idade e renda estudados. O consumo médio diário de alimentos pertencentes ao grupo de leite e derivados foi 1,35 porções. As relações cálcio/proteína e cálcio/fósforo foram 7,7:1 e 1:1,3, respectivamente. A presença de osteopenia/osteoporose foi verificada em 60 % das participantes, estando estatisticamente associada com a idade. Os resultados sugerem que a fortificação do pão de forma com cálcio pode ser uma alternativa para elevar o aporte de cálcio em mulheres adultas ao longo da vida.