ABSTRACT
The demand for sustainable and healthy food is increasing. Therefore, it is necessary to find new sources of functional ingredients for design of novel food products. Microalgae are reliable sources of functional ingredients, ready for exploitation with purpose of production of human food. This work explores consumers' acceptance of novel foods based on microalgae. To achieve natural and realistic eating location, sensory analysis was conducted in a real restaurant in Universitat Politècnica de València. A check-all-that-apply questionnaire and hedonic scale registered the consumers' expectations (N = 85), perceptions and acceptance, before and after taste of typical Valencian breadsticks. Food neophobia can affect acceptability of novel foods, thus, participants completed a test designed to measure their attitudes towards new food. Microalgae breadsticks have distinctive characteristics compared to control breadsticks, such as colour, flavour and odour, because of microalgae presence. Still, those breadsticks were as acceptable as the control breadsticks according to the consumer preferences. Consumers expected more differences amongst both breadsticks before tasting, but they lowered the differences in perception after trying them. Consumers consider that the product is healthier, and they would understand if it had greater expense. We believe this information can be useful for selling / marketing this novel product.
Subject(s)
Consumer Behavior , Food Handling , Taste Perception , Adult , Aged , Avoidant Restrictive Food Intake Disorder , Choice Behavior , Color , Female , Food Preferences , Humans , Male , Microalgae , Middle Aged , Odorants , TasteABSTRACT
La región andina de Chimborazo en Ecuador está situada en la zona central de la Región Interandina. La alimentación de las comunidades es esencialmente a base tubérculos (patata, oca, melloco y mashwa), granos (maíz, quinua y amaranto) y de leguminosas (chocho, haba, fréjol). Las características de la región han permitido la supervivencia de este tipo de cultivos que presentan una gran variabilidad en colores, formas y tamaños, y están asociados con cantidad de macro y micronutrientes, además de compuestos bioactivos. El objetivo de este trabajo es revisar los datos existentes sobre los componentes con potencial funcional presentes en los cultivos de tubérculos nativos de la región. Esta información servirá como base para la creación, en la Escuela Superior Politécnica de Chimborazo (ESPOCH), de una línea de investigación que estimule la conservación de estos cultivos como fuente de alimentos funcionales naturales (AU)
Chimborazo in Ecuador is located in the Middle Inter-Andean region. People from this region have utilized native tubers for their nutritional and medicinal properties since pre-hispanic time. The health-related properties of Andean tuber crops claimed from folklore use could be in part attributed to the antioxidants present in these crops. Currently there is a high interest in the search for edible plants as novel sources of health-promoting phytochemicals. Andean crops show variability in colors, forms and sizes, and also in primary nutrient constituents and bioactive secondary metabolites derived of a great genetic diversity, unfortunately poorly studied. The objective of this work is to review the existing data on the components with functional properties in the native tubers. The information extracted in this paper should serve to stimulate an increase in the evaluation of these crops as sources of functional foods, as well as to introduce a new research program in the Escuela Superior Politecnica de Chimborazo (ESPOCH) (AU)
Subject(s)
Humans , 24444 , Andean Ecosystem/methods , Antioxidants , Solanum tuberosum , Nutritive Value/physiology , Food Composition , Carotenoids , Polyphenols , Andean Ecosystem/classification , Andean Ecosystem/statistics & numerical data , Ecuador/epidemiology , Nutrition AssessmentABSTRACT
No disponible
Subject(s)
Humans , Male , Middle Aged , Thrombolytic Therapy/methods , Thrombolytic Therapy , Stroke/complications , Stroke/therapy , Stroke , Endocarditis, Bacterial/complications , Intracranial Hemorrhages/complications , Intracranial Hemorrhages , Systolic Murmurs/complications , Systolic Murmurs , Aphasia/complications , Dysarthria/complications , Paresis/complications , Intubation, Intratracheal/methods , Respiration, Artificial/methods , Echocardiography, Transesophageal/instrumentation , Echocardiography, Transesophageal/methods , Echocardiography, TransesophagealABSTRACT
In this study, we report a methodology which enables the determination of the degradation mechanisms responsible for catalyst deterioration under different accelerated stress protocols (ASPs) by combining measurements of the electrochemical surface area (ECSA) and Pt content (by X-ray fluorescence). The validation of this method was assessed on high surface area unsupported Pt nanoparticles (Pt-NPs), Pt nanoparticles supported on TaC (Pt/TaC) and Pt nanoparticles supported on Vulcan carbon (Pt/Vulcan). In the load cycle protocol, the degradation of Pt-NPs and Pt/Vulcan follows associative processes (e.g. agglomeration) in the first 2000 cycles, however, in successive cycles the degradation goes through dissociative processes such as Pt dissolution, as is evident from a similar decay of ECSA and Pt content. In contrast, the degradation mechanism for Pt nanoparticles dispersed on TaC occurs continuously through the dissociative processes (e.g. Pt dissolution or particle detachment), with similar decay rates of both Pt content and ECSA. In the start-up/shut-down protocol, high surface area Pt-NPs follow associative processes (e.g. Ostwald ripening) in the first 4000 cycles, after which the degradation continues through dissociative processes. On the other hand, dissociative mechanisms always govern the degradation of Pt/TaC under start-up/shut-down protocol conditions. Finally, we report that Pt nanoparticles supported on TaC exhibit the highest catalytic activity and long term durability of the three nanoparticle systems tested. This makes Pt/TaC a potentially valuable catalyst system for application in polymer electrolyte fuel cell cathodes.
Subject(s)
Thrombolytic Therapy , Thrombosis/drug therapy , Humans , Splenic Vein , Venous ThrombosisSubject(s)
Endocarditis, Bacterial/complications , Stroke/complications , Thrombolytic Therapy/adverse effects , Fatal Outcome , Fibrinolytic Agents/adverse effects , Fibrinolytic Agents/therapeutic use , Humans , Male , Middle Aged , Shock, Septic/complications , Stroke/diagnostic imaging , Stroke/drug therapy , Tissue Plasminogen Activator/adverse effects , Tissue Plasminogen Activator/therapeutic use , Tomography, X-Ray ComputedABSTRACT
In this paper, physico-chemical and structural properties of cut and cooked purple-flesh potato, green bean pods, and carrots have been studied. Three different cooking methods have been applied: traditional cooking (boiling water at 100 °C), cook-vide (at 80 and 90 °C) and sous-vide (at 80 °C and 90 °C). Similar firmness was obtained in potato applying the same cooking time using traditional cooking (100 °C), and cook-vide and sous-vide at 90 °C, while in green beans and carrots the application of the sous-vide (90 °C) required longer cooking times than cook-vide (90 °C) and traditional cooking (100 °C). Losses in anthocyanins (for purple-flesh potatoes) and ascorbic acid (for green beans) were higher applying traditional cooking. ß-Carotene extraction increased in carrots with traditional cooking and cook-vide (P < 0.05). Cryo-SEM micrographs suggested higher swelling pressure of starch in potatoes cells cooked in contact with water, such as traditional cooking and cook-vide. Traditional cooking was the most aggressive treatment in green beans because the secondary walls were reduced compared with sous-vide and cook-vide. Sous-vide preserved organelles in the carrot cells, which could explain the lower extraction of ß-carotene compared with cook-vide and traditional cooking. Sous-vide cooking of purple-flesh potato is recommended to maintain its high anthocyanin content. Traditional boiling could be recommended for carrots because increase ß-carotenes availability. For green beans, cook-vide, and sous-vide provided products with higher ascorbic acid content.
Subject(s)
Anthocyanins/analysis , Antioxidants/analysis , Ascorbic Acid/analysis , Cooking/methods , Hot Temperature , Vegetables/chemistry , beta Carotene/analysis , Daucus carota/chemistry , Fabaceae/chemistry , Humans , Solanum tuberosum/chemistry , Starch/chemistry , WaterABSTRACT
Dynamic non-classical nonlinear analyses show promise for improved damage diagnostics in materials that exhibit such structure at the mesoscale, such as concrete. In this study, nonlinear non-classical dynamic material behavior from standard vibration test data, using pristine and frost damaged cement mortar bar samples, is extracted and quantified. The procedure is robust and easy to apply. The results demonstrate that the extracted nonlinear non-classical parameters show expected sensitivity to internal damage and are more sensitive to changes owing to internal damage levels than standard linear vibration parameters.
ABSTRACT
Herein, we report a simple methodology for cleaning Pt nanoparticles, prepared by a colloidal synthesis and coated with polyvinylpyrrolidone, without loss of crystalline surface structure. To prove the removal of the polyvinylpirrolidone from a Pt surface without disturbing the superficial order, a cleaning method using a solution of H(2)O(2)/H(2)SO(4) was tested successfully for a Pt(111) single-crystal electrode. The decontamination method was then tested for two different types of nanoparticles by mixing the suspension of nanoparticles with H(2)O(2)/H(2)SO(4) and subsequent centrifugation. The resulting voltammetric profiles of platinum particles synthesized by the colloidal method employing PVP show a marked presence of the adsorption-state characteristic of (111) ordered surface domains. The presence of the well-ordered domains present on the surface of the nanoparticles was confirmed by using the irreversible adsorption of bismuth, tellurium and germanium.
Subject(s)
Nanoparticles/chemistry , Platinum/chemistry , Povidone/isolation & purification , Catalysis , Crystallization , Electrochemical Techniques , Electrodes , Hydrogen Peroxide/chemistry , Nanoparticles/ultrastructure , Surface PropertiesABSTRACT
Objective: To test the reliability of dietary intake data measured with an online food frequency questionnaires (FFQ) applied to a university population by comparing the results with those from a paper and pencil version. Materials and methods: A total of 50 students were recruited from the second-year Food Technology course at the Universitat Politècnica de València (Comunidad Valenciana, Spain) in the academic year 2008-2009. The students were between the ages of 20-32. The participants completed both presentation modes of the FFQ (paper and pencil and online) in a cross-over study with a time interval of 3-week. To study the effect of ordering of the questionnaires, participants were randomly assigned to group A (paper and pencil FFQ first) and group B (online FFQ first). Both self-administered semi-quantitative presentations of the FFQ included 84 food items divided into six groups (dairy products; eggs, meat and fish; vegetables, legumes and fruits; bread, cereals and similar; oils, fats and sweets; beverages and pre-cooked). Participants were asked how frequently and how much each food item they had consumed in the previous year. Results: The response rate was 78% (39 students, 23% men and 77% women). For the total sample, the median dietary intakes were higher for the paper and pencil FFQ than the online version for energy (2,077 vs. 1,635 kcal/day), proteins (96 vs. 88 g/day), carbohydrates (272 vs. 211 g/day), and fat (70 vs. 58 g/day), respectively. These differences were statistically significant. However, there were not significant differences between the two presentations when the consumption by groups of food was calculated, except for beverages and pre-cooked group. Conclusions: The pilot testing showed that this online FFQ is a useful tool for estimating the intake of food groups in this university population. On the other hand, the differences found in the results of the absolute quantities of energy and nutrients intakes were not clear. These differences could be due to the problems that the participants had for reporting portion size in the paper and pencil FFQ as photographs of portion sizes were not presented (AU)
Objetivo: Estudiar la fiabilidad de los datos de ingesta dietética medidos con un cuestionario de frecuencia de consumo de alimentos online aplicado a la población universitaria comparando los resultados con los obtenidos mediante el cuestionario en formato papel. Materiales y métodos: Un total de 50 estudiantes del segundo curso de Ciencia y Tecnología de los Alimentos en la Universitat Politècnica de València (Comunidad Valenciana, España) en el año académico 2008-2009 participaron en el estudio. El rango de edad de los participantes oscilaba entre 20 y 32 años. En un estudio cruzado, los participantes completaron ambas presentaciones del cuestionario (formato papel y versión online) en un intervalo de 3 semanas. Para estudiar el efecto del orden de autoadministración de los cuestionarios, los participantes fueron asignados al azar en el grupo A (realizaron primero el cuestionario en formato papel) y en el grupo B (realizaron primero la versión online). Ambas presentaciones del cuestionario eran autoadministradas y semicuantitativas e incluían una lista de 84 alimentos divididos en seis grupos (productos lácteos; huevos, carne y pescado; vegetales, legumbres y frutas; pan, cereales y similares; aceites, grasas y dulces; bebidas y precocinados). Para cada alimento que los participantes habían consumido el año anterior debían indicar la frecuencia y la cantidad consumida. Resultados: La tasa de respuesta fue del 78% (39 estudiantes, 23% hombre y 77% mujeres). Para el total de la muestra, la mediana de la ingesta dietética fue mayor en el cuestionario en papel que en la versión online para la energía (2.077 vs 1.635 kcal/día), las proteínas (96 vs 88 g/día), los hidratos de carbono (272 vs 211 g/día) y las grasas (70 vs. 58 g/día), respectivamente. Estas diferencias fueron estadísticamente significativas. Sin embargo, no hubieron diferencias significativas entre ambas presentaciones cuando el consumo por grupos de alimentos fue calculado, excepto para el grupo de bebidas y precocinados. Conclusiones: El estudio piloto mostró que este cuestionario online es una herramienta útil para estimar la ingesta de los grupos de alimentos en esta población universitaria. En cambio, las diferencias encontradas en los resultados de energía y nutrientes no fueron concluyentes. Éstas pudieron deberse a los problemas que tuvieron los participantes para indicar el tamaño de porción ingerida en el cuestionario en papel porque las fotografías de los tamaños de ración no se mostraban (AU)
Subject(s)
Humans , Male , Female , Adolescent , Young Adult , Feeding Behavior , Feeding Behavior , Nutrition Surveys/statistics & numerical data , Eating , Modalities, Hourly , Students/statistics & numerical data , User-Computer Interface , Surveys and QuestionnairesABSTRACT
Objective: To introduce and describe a new tool called UPV-FFQ to evaluate dietary intake of the university population. The new tool consists principally in a selfadministered online food frequency questionnaire (FFQ). Materials and methods: The tool UPV-FFQ has been developed by means of web pages applying the technology ASP.NET 2.0 and using the database SQL Server 2005 as support. To develop the FFQ has been used as model the paper and pencil FFQ called "Dieta, salud y antropometría en la población universitaria". Results: The tool has three parts: (1) a homepage, (2) a general questionnaire and (3) a FFQ. The FFQ has a closed list of 84 food items commonly consumed in Valencia region. The respondents has to indicate the food items that they consume (2 possible options), the frequency of consumption (9 response options) and the quantity consumed (7 response options). The UPV-FFQ has approximately 250 color photographs that represents to three portion sizes. The photographs are useful to help the respondents to choose the portion sizes that more adjusts to their habitual portions. The new tool provides quantitative information of the habitual intake of 31 nutritional parameters and provides qualitative information of the general questionnaire. A pilot study was done for a total of 57 respondents. The media time spend to fill in was 15 minutes. Conclusions: The pilot study concluded that the questionnaire was ease-of-use, low cost and time-effectiveness questionnaire. The format and the sequence of the questions were easily understood (AU)
Objetivo: Introducir y describir una nueva herramienta llamada UPV-FFQ para evaluar la ingesta dietética de la población universitaria. Esta nueva herramienta consiste principalmente en un cuestionario de frecuencia de consumo de alimentos (CFCA) autoadministrado online. Materiales and métodos: La herramienta UPV-FFQ se ha desarrollado a través de páginas web aplicando la tecnología ASP.NET 2.0 y usando la base de datos SQL Server 2005 como soporte. Para desarrollar este FFQ se ha empleado como modelo el cuestionario en papel llamado Dieta, salud y antropometría en la población universitaria. Resultados: La herramienta consta de tres partes: 1) una página de introducción; 2) un cuestionario general y 3) un CFCA. El CFCA consta de una lista cerrada de 84 alimentos comúnmente consumidos en la región valenciana. Los encuestados deben indicar qué alimentos consumen (2 posibles opciones de respuesta), la frecuencia de ingesta (9 opciones de respuesta) y la cantidad ingerida (7 opciones de respuesta). El UPV-FFQ presenta aproximadamente 250 fotografías a color con tamaños de ración para cada alimento para ayudar a los encuestados a escoger el tamaño de ración que más se ajusta a su porción habitual. La herramienta proporciona información cuantitativa de la ingesta habitual de 31 parámetros nutricionales y también proporciona información cualitativa proveniente del cuestionario general. Se realizó un estudio piloto con un total de 57 participantes con características similares a la población de estudio. El tiempo medio que emplearon para rellenarlo fue de 15 minutos. Conclusiones: El estudio piloto concluyó que el UPVFFQ era fácil de manejar, de bajo coste y de gran eficacia. Además, entendieron fácilmente el formato y la secuencia de las preguntas (AU)
Subject(s)
Humans , Nutrition Surveys/methods , Feeding Behavior , Nutrition Assessment , Surveys and Questionnaires , Feeding Behavior , Food Preferences , Students/statistics & numerical data , User-Computer InterfaceABSTRACT
The food frequency questionnaires are widely used in epidemiological researches like dietary assessment method. Traditionally, they have been self-administered in paper but the use of information and communication technologies has led to develop Internet and computerized food frequency questionnaires. It is the objective of this article to offer a global perspective of the new technologies applied to FFQ. It will be presented the purpose of the food frequency questionnaire, the number of strengths of the web-based surveys versus print-surveys and finally, a description of the manuscripts that have used web-based and computerized FFQ (AU)
Los cuestionarios de frecuencia de consumo de alimentos son muy utilizados en investigaciones epidemiológicas como método para evaluar la dieta. Tradicionalmente, han sido autoadministrados en papel, pero el uso de las tecnologías de la información y la comunicación (TICs) ha permitido desarrollar cuestionarios de frecuencia de consumo de alimentos computerizados y a través de Internet. El objetivo de este artículo es ofrecer una perspectiva actual del uso de las nuevas tecnologías aplicadas al diseño e interpretación de los cuestionarios de frecuencia de consumo de alimentos. En el presente trabajo se resumen los objetivos de los cuestionarios de frecuencia de consumo de alimentos, las ventajas de los cuestionarios autoadministrados por Internet frente a los administrados en papel y finalmente, se describirán diferentes estudios que han usado cuestionarios de frecuencia de consumo de alimentos autoadministrados mediante el uso de ordenador o a través de Internet (AU)
Subject(s)
Humans , Nutrition Surveys/instrumentation , Technological Development , Feeding Behavior , Surveys and Questionnaires , User-Computer InterfaceABSTRACT
The food frequency questionnaires are widely used in epidemiological researches like dietary assessment method. Traditionally, they have been self-administered in paper but the use of information and communication technologies has led to develop Internet and computerized food frequency questionnaires. It is the objective of this article to offer a global perspective of the new technologies applied to FFQ. It will be presented the purpose of the food frequency questionnaire, the number of strengths of the web-based surveys versus print-surveys and finally, a description of the manuscripts that have used web-based and computerized FFQ.
Subject(s)
Diet Surveys/methods , Surveys and Questionnaires , Computers , Epidemiologic Methods , Feeding Behavior , Humans , InternetABSTRACT
OBJECTIVE: To test the reliability of dietary intake data measured with an online food frequency questionnaires (FFQ) applied to a university population by comparing the results with those from a paper and pencil version. MATERIALS AND METHODS: A total of 50 students were recruited from the second-year Food Technology course at the Universitat Politècnica de València (Comunidad Valenciana, Spain) in the academic year 2008-2009. The students were between the ages of 20-32. The participants completed both presentation modes of the FFQ (paper and pencil and online) in a cross-over study with a time interval of 3-week. To study the effect of ordering of the questionnaires, participants were randomly assigned to group A (paper and pencil FFQ first) and group B (online FFQ first). Both self-administered semi-quantitative presentations of the FFQ included 84 food items divided into six groups (dairy products; eggs, meat and fish; vegetables, legumes and fruits; bread, cereals and similar; oils, fats and sweets; beverages and pre-cooked). Participants were asked how frequently and how much each food item they had consumed in the previous year. RESULTS: The response rate was 78% (39 students, 23% men and 77% women). For the total sample, the median dietary intakes were higher for the paper and pencil FFQ than the online version for energy (2,077 vs. 1,635 kcal/day), proteins (96 vs. 88 g/day), carbohydrates (272 vs. 211 g/day), and fat (70 vs. 58 g/day), respectively. These differences were statistically significant. However, there were not significant differences between the two presentations when the consumption by groups of food was calculated, except for "beverages and pre-cooked" group. CONCLUSIONS: The pilot testing showed that this online FFQ is a useful tool for estimating the intake of food groups in this university population. On the other hand, the differences found in the results of the absolute quantities of energy and nutrients intakes were not clear. These differences could be due to the problems that the participants had for reporting portion size in the paper and pencil FFQ as photographs of portion sizes were not presented.
Subject(s)
Diet Surveys/methods , Surveys and Questionnaires , Adult , Body Weight , Cross-Over Studies , Data Interpretation, Statistical , Dietary Carbohydrates , Dietary Fats , Dietary Proteins , Energy Intake , Feeding Behavior , Female , Food , Food Preferences , Humans , Internet , Life Style , Male , Motor Activity , Pilot Projects , Reproducibility of Results , Smoking , Universities , Young AdultABSTRACT
OBJECTIVE: To introduce and describe a new tool called UPV-FFQ to evaluate dietary intake of the university population. The new tool consists principally in a self-administered online food frequency questionnaire (FFQ). MATERIALS AND METHODS: The tool UPV-FFQ has been developed by means of web pages applying the technology ASP.NET 2.0 and using the database SQL Server 2005 as support. To develop the FFQ has been used as model the paper and pencil FFQ called "Dieta, salud y antropometría en la población universitaria". RESULTS: The tool has three parts: (1) a homepage, (2) a general questionnaire and (3) a FFQ. The FFQ has a closed list of 84 food items commonly consumed in Valencia region. The respondents has to indicate the food items that they consume (2 possible options), the frequency of consumption (9 response options) and the quantity consumed (7 response options). The UPV-FFQ has approximately 250 color photographs that represents to three portion sizes. The photographs are useful to help the respondents to choose the portion sizes that more adjusts to their habitual portions. The new tool provides quantitative information of the habitual intake of 31 nutritional parameters and provides qualitative information of the general questionnaire. A pilot study was done for a total of 57 respondents. The media time spend to fill in was 15 minutes. CONCLUSIONS: The pilot study concluded that the questionnaire was ease-of-use, low cost and time-effectiveness questionnaire. The format and the sequence of the questions were easily understood.
Subject(s)
Diet Surveys/methods , Diet , Eating , Internet , Surveys and Questionnaires , Feeding Behavior , Female , Humans , Male , Pilot Projects , Reproducibility of Results , Spain , Students , Universities , Young AdultABSTRACT
Cerebral lesions after a stroke present different clinical features depending on the neurological structures affected. Complications after an injury in the respiratory center may lead to prolonged mechanical ventilation. Among these possible complications there is a rare neurological condition called "Ondine's curse" that is caused by spontaneous breathing failure. Patients who suffer this syndrome cannot breathe automatically and need to control their respiration consciously and voluntarily. We report the case of a woman who developed a syndrome of central alveolar hypoventilation secondary to an injury in respiratory center after a hemorrhagic stroke. We have reviewed the etiology, physiopathology, diagnosis and treatment of patients with Ondine's curse.
Subject(s)
Hypoventilation/etiology , Ventilator Weaning , Adult , Female , Humans , Stroke/complications , Stroke/therapy , Treatment FailureABSTRACT
Las lesiones cerebrales secundarias a un ictus se manifiestan según la estructura neurológica afectada. Las complicaciones por afectación del centro respiratorio pueden ser causa de una ventilación mecánica prolongada. Entre estas complicaciones se encuentra la llamada «maldición de Ondine», que hace referencia a una rara enfermedad neurológica causada por el fallo en la respiración espontánea. Los pacientes no son capaces de respirar automáticamente, y necesitan consciente y voluntariamente realizar la respiración por ellos mismos. En este artículo presentamos el caso de una mujer que tras un ictus hemorrágico cerebeloso desarrolla un síndrome de hipoventilación alveolar central secundario a una lesión del centro respiratorio. Realizamos una revisión de la etiología, el mecanismo fisiopatológico, el diagnóstico y el tratamiento del síndrome de Ondine (AU)
Cerebral lesions after a stroke present different clinical features depending on the neurological structures affected. Complications after an injury in the respiratory center may lead to prolonged mechanical ventilation. Among these possible complications there is a rare neurological condition called «Ondine's curse» that is caused by spontaneous breathing failure. Patients who suffer this syndrome cannot breathe automatically and need to control their respiration consciously and voluntarily. We report the case of a woman who developed a syndrome of central alveolar hypoventilation secondary to an injury in respiratory center after a hemorrhagic stroke. We have reviewed the etiology, physiopathology, diagnosis and treatment of patients with Ondine's curse (AU)
Subject(s)
Humans , Female , Adult , Ventilator Weaning , Hypoventilation/etiology , Stroke/complications , Stroke/therapy , Treatment FailureABSTRACT
The aim of this paper is to evaluate the compatibility of sewage sludge ash (SSA) with various types of commercially available cements (CEM I and CEM II types, cements with several proportions of clinker). The behaviour of mortars fabricated with various percentages (10-30% by weight) of the cement replaced by SSA has been analyzed in terms of workability, mechanical strength, porosity and shrinkage/expansion. SSA exhibits moderate pozzolanic activity; the highest compressive strengths were obtained with 10% of the cement replaced by SSA. The CEM II/B-M (V-LL) 42.5R cement is considered ideal for preparing mortars containing SSA. Shrinkage data demonstrate that sulphates present in SSA are not reactive towards cement.
Subject(s)
Conservation of Natural Resources/methods , Construction Materials/analysis , Sewage/chemistry , Incineration , Mechanics , Microscopy, Electron, Scanning , Particle Size , Time FactorsABSTRACT
New composite materials based on an alkali-resistant glass-fibre reinforced cement (AR-GRC) system are being developed by using fly ash (FA) produced at coal thermoelectric power plants, and fluid catalytic cracking catalyst residue (FC3R) from the petrol industry as cement replacement materials. These wastes are reactive from the pozzolanic viewpoint, and modify the nature and the microstructure of the cement matrix when a part of the Portland cement is replaced in the formulation of GRC. Several microstructural and mechanical aspects are being studied for AR-GRC systems. The behaviour of composites exposed to ageing shows that the pozzolanic activity of the ground FA added in high amounts and its mixture with the FC3R increase the flexural strength and no evidences of strength decay are observed. Additionally, the fibres due to the high alkalinity of the cementing matrix can be deteriorated. Fibres in the control (only Portland cement) and FC3R containing composites were attacked, whereas composites with FA and their mixture with FC3R show that the fibres have not been attacked, due to the pozzolanic activity of replacing materials that reduce the calcium hydroxide content in the cementing matrix.