[pt] Neste trabalho foi realizado um estudo comparativo do desempenho mecânico e da durabilidade de concretos reforçados com macrofibras discretas de sisal e polipropileno. Foram utilizadas duas matrizes cimentícias com teores distintos de material pozolânico. As duas fibras, com comprimento de 51 mm, foram incorporadas em dosagens de 3 a 15 kg/m3. Foram realizados ensaios de tração direta para ambas as fibras, obtendo-se valores de tensões equivalentes. Para caracterização mecânica dos compósitos, foram realizados ensaios de flexão em três pontos sob carregamento monotônico, de acordo com o procedimento da norma EN 14651. Também se avaliou este comportamento sob carregamentos cíclicos. Na avaliação da aderência fibra-matriz, ensaios de arrancamento foram realizados. A fibra de sisal apresentou menor aderência nas duas matrizes. Todos os compósitos com fibras de sisal e polipropileno apresentaram comportamento deflection softening quando submetidos à flexão. Para se obter desempenho mecânico na flexão similar para ambas as fibras, foi necessário aproximadamente o dobro da dosagem de fibras de sisal. De acordo com a classificação proposta pelo fib Model Code, essas fibras podem substituir parcialmente ou integralmente o reforço convencional no estado limite último. A durabilidade dos compósitos foi estudada por meio de processo de envelhecimento acelerado, utilizando-se ciclos de molhagem e secagem. A utilização do reforço de sisal na matriz com maior alcalinidade apresentou degradação, enquanto que sua incorporação na matriz livre de hidróxido de cálcio não resultou em perdas mecânicas após os ciclos. Concretos reforçados com fibras de polipropileno não apresentaram degradação pelos processos de envelhecimento acelerado. / [en] This work aims to present a comparative study of the mechanical performance and durability of concretes reinforced with discrete sisal and polypropylene macrofibers. Two cementitious matrices with different pozzolan material content were used. The both fibers were incorporated into fractions of 3 to 15 kg/m3 and were 51 mm long. Direct tensile tests were performed for the fibers, achieving equivalent stress values. For mechanical characterization of the composites, three-point flexural tests were performed under monotonic loading in accordance with the EN 14651 procedure. The behavior under cyclic loading was also investigated. To evaluate the fiber-matrix interaction, pull out tests were performed. The sisal fiber showed lower adhesion with the two matrices. All the composites with sisal and polypropylene fibers presented deflection softening behavior when subjected to flexural loads. In order to obtain similar flexural mechanical performance for both fibers, approximately twice dosage of sisal fiber was required. According to the classification proposed by fib Model Code, these fibers can partially or fully replace the conventional reinforcement at ultimate limit state. The durability of the composites was studied by accelerated aging process through wetting and drying cycles. The use of sisal fibers as reinforcement in the matrix with higher alkalinity showed degradation, while its incorporation into the matrix free of calcium hydroxide did not result in mechanical losses after the cycles. Concretes reinforced with polypropylene fibers did not present degradation caused by accelerated aging processes.

La presente investigación se basa en el estudio de la influencia de microfibras sintéticas de polipropileno en las propiedades mecánicas y plásticas de losas de concreto f’c=210 kg/cm2 expuestas a altas temperaturas en el departamento de Ucayali. Para ello, se procedió a realizar mezclas de concreto con dos microfibras de polipropileno de 20 y 30 milímetros de longitud, a su vez, dichas mezclas fueron dosificadas con 600, 900 y 1200 g/m3 de concreto y evaluarlas respecto a contracción platica, resistencia a compresión y flexión residual. El primer ensayo, se realizó en base a la Norma ASTM C-1579 (Método de prueba estándar para evaluar el agrietamiento por contracción plástica del hormigón reforzado con fibra restringida), evaluando losas de concreto de 560x355x100 mm. sometidas a temperaturas mayores a 27°C y velocidades de viento de 8 km/h y compararlas entre la muestra patrón y muestras reforzadas con microfibras; obteniéndose una Relación de Reducción de Grietas (CRR) máxima de 68.50% para el concreto con fibra de 300 mm. y una dosificación de 1200 g/m3. Para el ensayo de compresión, guiado por la NTP 339.034 – ASTM-C39 (Método de ensayo normalizado para la determinación de la resistencia a la compresión del concreto, en muestras cilíndricas) se ensayaron probetas de 6x12 pulgadas para cada longitud de y dosificación de microfibra para compararlas respecto a la mezcla convencional; para el concreto con microfibra de 30 mm se obtuvo un incremento promedio de 8% para una dosificación de 1200 gr/m3 para un tiempo de curado de 28 días, por otro lado, la de 20 mm alcanzo incrementos máximos de 7% para la misma dosificación y tiempo de curado que el anterior. Para el último ensayo, se basó de la Norma ASTM C 1399 (Método de ensayo para determinar el esfuerzo residual promedio del concreto reforzado con fibra), en la cual se evaluaron muestras prismáticas de 100x100x350 mm sometiéndolas a cargas para obtener cual es la tensión residual que soportan a diferentes deformaciones para cada tipo de microfibras y dosificaciones. El concreto reforzado con microfibra sintética de 30 mm, obtuvo mayores valores de tensiones residuales (1.95 MPa para 1200 gr/m3) para todas las dosificaciones estudiadas en comparación a la de 20 mm. (1.86 MPa 1200 gr/m3). Al finalizar la experimentación, se concluyó que la microfibra sintética de polipropileno de 30 mm tuvo mejor desenvolvimiento que la de 20 mm para los 3 ensayos realizados. Además, se observó una relación directa entre el aumento de las propiedades mecánicas y plásticas con la cantidad de dosificación incorporada al concreto. / This research is based on the study of the influence of synthetic polypropylene microfibers on the mechanical and plastic properties of concrete slabs f’c = 210 kg / cm2 exposed to high temperatures in Ucayali. For this, concrete mixtures with two microfibers of 20 and 30 millimeters in length were made, in turn, dosages of 600, 900 and 1200 g / m3 of concrete were included and evaluated for plastic contraction, compressive strength and residual flexion. The first test was carried out on the basis of ASTM C-1579 (Standard test method to evaluate cracking by plastic contraction of reinforced fiber reinforced concrete), evaluating concrete slabs of 560x355x100 mm subjected to temperatures greater than 27 ° C and wind speeds of 8 km / h and compare them between standard samples and reinforced with microfibers; obtaining maximum Crack Reduction Ratio (CRR) of 68.50% for concrete with 300 mm fiber. and a dosage of 1200 g / m3. For the compression test, guided by Standard NTP 339.034 - ASTM-C39 (Standard test method for the determination of the compressive strength of concrete, in cylindrical samples) 6x12 inch specimens were tested for each microfiber and dosing to compare them with respect to the conventional mixture; for concrete with 30 mm microfiber an average increase of 8% was obtained for a dosage of 1200 gr / m3 for a curing time of 28 days, on the other hand, the 20 mm reached maximum increases of 7% for the same dosage and cure time than the previous one. For the last test, it was based on ASTM C 1399 (Test method to determine the average residual stress of fiber reinforced concrete), in which prismatic samples of 100x100x350 mm were evaluated by subjecting them to loads to obtain what the residual tension is that support different deformations for each type of microfibers and dosages. The reinforced concrete with synthetic microfiber of 30 mm, obtained higher values ​​of residual stresses (1.95 MPa for 1200 gr / m3) for all the dosages studied in comparison to that of 20 mm. (1.86 MPa 1200 gr / m3). At the end of the experimentation, it was concluded that the 30 mm polypropylene synthetic microfiber had a better performance than the 20 mm microfiber for the 3 tests performed. In addition, a direct relationship was observed between the increase in mechanical and plastic properties with the amount of dosage incorporated into the concrete. / Tesis

With the population expected to grow dramatically in the future. The existing state of the ecosystem appears to be worse in the future. One of the key culprits that has been wreaking havoc on the ecosystem is the use of plastic that is used to produce composites. Composites, because to its versatility, has applications in all areas, and as the population grows, so will the demand for them. This can be reduced by using biodegradable and natural materials. The study is done in collaboration with the company Trifilon. The raw materials of the mixture are compared, and the best polymer, fibers, and additives are chosen. Composites made from synthetic raw materials are being replaced by bio-composites, which contain one natural component. The material selected are polypropylene as the polymer, maleic anhydride as compatibilizer and glass fiber for composite while hemp fiber for Bio-composite. To achieve optimal mechanical qualities, the mixture is created using varied amounts of essential components. The mechanical properties aid in defining the industries in which the material can be employed. There are various combinations of raw materials available with varying fiber content, from which the best proportion of the fiber is chosen. For composites and Bio-composites, the fiber content in the mixture is 10% to generate the best material with the appropriate adaptability and flexibility, allowing the material to be used and have applications in several industries. A comparative life cycle evaluation is used to compare the environmental impact of both materials' production procedures. The assessment model was created with the help of a literature review to generate the optimal recipe for composite and bio-composite materials. In most impact categories, bio-composite materials were found to be more sustainable than composite materials. The usage of Polypropylene as a raw material has the greatest influence on global warming, with glass fiber contributing more to global warming than hemp fiber. Future studies could include replacing Polypropylene with natural polymer and hemp fiber with a combination of synthetic and natural fiber to have strong mechanical properties from the synthetic and eco-friendliness from the natural fiber respectively. / Med befolkningen som förväntas växa dramatiskt i framtiden. Ekosystemets befintliga tillstånd verkar vara sämre i framtiden. En av de viktigaste bovarna som har orsakat förödelse på ekosystemet är användningen av plast som används för att producera kompositer. Kompositer har, på grund av sin mångsidighet, tillämpningar inom alla områden, och när befolkningen växer kommer efterfrågan på dem att öka. Detta kan minskas genom att använda biologiskt nedbrytbara och naturliga material. Studien görs i samarbete med företaget Trifilon. Blandningens råmaterial jämförs och den bästa polymeren, fibrerna och tillsatserna väljs. Kompositer tillverkade av syntetiska råvaror ersätts av biokompositer som innehåller en naturlig komponent. Materialet som väljs är polypropen som polymer, maleinsyraanhydrid som kompatibiliseringsmedel och glasfiber för komposit medan hampafiber för biokomposit. För att uppnå optimala mekaniska egenskaper skapas blandningen med olika mängder väsentliga komponenter. De mekaniska egenskaperna hjälper till att definiera de branscher där materialet kan användas. Det finns olika kombinationer av råvaror med varierande fiberhalt, från vilka den bästa andelen av fibern väljs. För kompositer och biokompositer är fiberinnehållet i blandningen 10 % för att generera det bästa materialet med lämplig anpassningsförmåga och flexibilitet, vilket gör att materialet kan användas och ha tillämpningar inom flera industrier. En jämförande livscykelutvärdering används för att jämföra miljöpåverkan från båda materialens produktionsprocedurer. Bedömningsmodellen skapades med hjälp av en litteraturöversikt för att generera det optimala receptet för komposit- och biokompositmaterial. I de flesta påverkanskategorier visade sig biokompositmaterial vara mer hållbara än kompositmaterial. Användningen av polypropen som råvara har störst inflytande på den globala uppvärmningen, med glasfiber som bidrar mer till den globala uppvärmningen än hampafiber. Framtida studier kan innefatta att ersätta polypropen med naturlig polymer och hampafiber med en kombination av syntetiska och naturliga fibrer för att ha starka mekaniska egenskaper från syntet respektive miljövänlighet från naturfiber.

[pt] O presente trabalho investigou o comportamento mecânico do concreto projetado com fibras aplicado nas escavações da mina Cuiabá e o seu controle tecnológico através do ensaio de duplo puncionamento. Para essa pesquisa utilizouse o traço desenvolvido pelos engenheiros da mina Cuiabá com dois tipos diferentes de fibra sintética e uma fibra de aço. Inicialmente, caracterizou-se o material compósito através de ensaios de flexão em prismas (EN 14651) e de arrancamento. Em seguida, os resultados obtidos foram utilizados em conjunto com os ensaios de flexão em painéis circulares (ASTM C1550), quadrados (EN 14488-5) e de larga escala para o dimensionamento do sistema de suporte utilizado na mina Cuiabá. As frações mais baixas de fibras sintéticas são mais indicadas nos locais onde a qualidade da rocha é razoável ou boa, enquanto as fibras de aço podem ser aplicadas onde a qualidade do maciço rochoso é classificada como muito fraca. Em relação ao controle tecnológico do concreto com fibras, os ensaios de duplo puncionamento realizados em máquinas mais rígidas são mais eficientes em diminuir a extensão da instabilidade pós-fissuração, limitar os erros nas correlações com os ensaios de flexão (EN 14651) e em reduzir a variação das propriedades mecânicas do material. A aplicação do ensaio de duplo puncionamento com controle fechado pela corrente extensométrica foi o método mais efetivo em limitar a instabilidade pós-fissuração independente da máquina de ensaios selecionada. / [en] The present work investigated the mechanical behavior of the fiber reinforced shotcrete applied at the Cuiabá mine excavation and its quality control through the double punch test. For this research, the mix composition was developed by Cuiabá mine Engineers with the addition of two different types of synthetic fibers and one steel fiber. Firstly, the cement based composite was studied at the material level through bending (EN 14651) and pullout tests. Thereafter, the support system of the Cuiabá mine excavation was designed based on round (ASTM C1550), square (EN 14488-5) and large scale panel tests. The application of lower synthetic fiber volume fractions was more suited for the areas with good quality rock indexes, while steel fibers were better suited at field with lower rock classes. Regarding the quality control of FRC, the double punch tests that were conducted in stiffer testing machines were more effective in reducing the post-peak instability, in limiting the errors in the correlations with bending tests (EN 14651) and in reducing the mechanical properties variations of the material. Finally, the application of the double punch test with closed-loop control of the circumferential extensometer turned to be the most effective method in limiting the post-peak instability regardless of the selected machine.

Si la sueur fraîchement émise par le corps humain est inodore, la dégradation de celle-ci par la flore bactérienne cutanée produit des composés volatils malodorants, responsables des odeurs de transpiration. Les odeurs de transpiration apparaissent également sur les vêtements au cours de leur utilisation, particulièrement sur les textiles réalisés en fibres synthétiques. Ce travail a pour but d’améliorer la compréhension du phénomène d’émanation d’odeurs en étudiant l’effet du sujet testé, l’effet de la flore bactérienne et l’effet du textile sur les émissions de composés volatils malodorants.L’intérêt de ce travail réside dans l’approche globale de la problématique des odeurs de transpiration et dans la diversité des méthodes de mesure mises en place, tant dans l’étude de la flore microbiologique que dans les méthodes de mesures des composés odorants émis.Dans un premier temps, le dénombrement simultané de la flore bactérienne sur la peau et sur le vêtement a été réalisé sur un échantillon de 15 sujets à l’issue d’un exercice physique. Cette expérimentation a permis d’évaluer le taux de transfert bactérien moyen lors d’une activité sportive et d’étudier son rôle dans l’émission d’odeurs. Ensuite, afin d’affiner ces résultats, une méthode basée sur la biologie moléculaire a été mise en place pour réaliser le suivi qualitatif de la stabilité de la flore commensale axillaire d’un sujet pendant 3 mois. Le transfert bactérien spécifique entre la peau du testeur et le vêtement a été étudié pour 4 matières textiles sélectionnées (dont le coton et le PET). Ceci a permis de déterminer le rôle du transfert bactérien spécifique dans l’émission des odeurs à partir de textile.Enfin, le dernier chapitre est consacré à l’étude de l’émission de composés volatils et odorants à l’aide de mesures olfactives et d’un nez électronique au cours du temps par 8 composants textiles sélectionnés. Après traitement statistique par analyse en composante principale et étude détaillée des mesures, 9 composés chimiques ont été identifiés comme indicateurs d’un comportement textile malodorant. Ces derniers pourraient être utilisés dans la mise en place d’une méthode ciblée de mesure physico-chimique des mauvaises odeurs.Ce travail a permis de déterminer l’impact de chacun des facteurs sujet, flore bactérienne et textile dans l’émission d’odeurs. En outre, ce travail ouvre des perspectives sur l’étude des contaminations bactériennes par contact, mais également dans l’étude des odeurs, sur les phénomènes de désorption de molécules volatiles à partir de différentes matrices textiles et sur les solutions pouvant être envisagées pour limiter les émissions odorantes à partir de textiles. / Fresh human sweat is odorless. Odoriferous volatile compounds are produced by the metabolism of bacteria living on the skin, generating strong malodor. Sweaty body odors do also appear on clothes during use, and especially on synthetic fabrics. The aim of this document is to improve understanding of odor emission by investigating subject effect, microbiota effect and fabric effect on the emission of odoriferous volatile compounds.Odors of perspiration are hereby globally approached with a wide use of methods and experimental devices, for microbial flora study as well as for odoriferous volatile compounds emission study.First, microflora enumeration has been simultaneously processed on the skin and on the fabric after exercise for 15 subjects. This experiment allowed an evaluation of the average bacterial transfer yield during physical activity and the beginning of the investigation of its effect on odor emission.A molecular biology methodology has then been developed in order to refine these results. Monitoring of qualitative composition of the microbiota has been performed to study the stability of the armpit’s ecosystem on a subject during 3 months. Specific microbial transfer from subject’s skin to clothe has been performed for 4 textile fabrics (including cotton and PET). This leaded to characterize the effect of specific bacterial transfer on odor emission from fabric.The last chapter is dedicated to the study of the emission of odoriferous volatile compounds over time using olfactory measurements and electronic nose for 8 selected fabrics. Principal component analysis targeted 9 chemical compounds that have been selected as malodorous behavior indicators for a given fabric. Those 9 compounds could be used for setting up a fitted physicochemical method of malodor.To conclude, this study helped to understand the effect of 3 factors in odor perception from a fabric after sport : subject, microbial flora and fabric. Perspectives have been charted on contact microbial contamination, but also on odor, and especially on desorption of odoriferous volatile molecules from a textile or knitted matrix. The solutions that could be used to limit malodorous emission from fabrics have also been discussed.