Doctor of Philosophy / Department of Civil Engineering / Kyle A. Riding / The cement industry is an important component in the quest to reduce global greenhouse gas emissions because of vast amounts of cement used annually. Incorporating supplementary cementitious materials (SCMs) into concrete is one alternative to reduce cement production and thereby reduce greenhouse gas emissions. This study investigated three types of agricultural residues, namely corn stover, wheat straw, and rice straw, in addition to bioethanol byproducts as potential resources for SCM production for concrete applications. Pretreatments, commonly used in bioethanol production, were used to improve pozzolanic reactivity of corn stover ash (CSA), wheat straw ash (WSA), and rice straw ash (RSA) in cementitious systems. In the first part of this research, the impact of distilled water and dilute hydrochloric acid pretreatments on pozzolanic reactivity of WSA, RSA, and CSA were studied. Results showed that pretreatments, particularly dilute acid, improved pozzolanic properties of CSA, WSA, and RSA by removing potassium and phosphorous from the biomass prior to ashing. In addition, WSA and RSA were shown to have similar pozzolanic reactivity to that of silica fume. In the second part of this study, suitability of high lignin residue (HLR), a bioethanol byproduct, for SCM production was investigated. It was shown that burning high lignin residue produces HLR ash that is very reactive in cementitious materials and can be used as a reactive SCM in concrete. The impact of each step in the production of bioethanol on the quality of bioethanol byproduct for subsequent burning and use in concrete was also studied. Sodium hydroxide and sulfuric acid pretreatments and enzymatic hydrolysis were used. Results revealed that sodium hydroxide pretreatment of the biomass have negative impact on biomass ash properties for concrete use because sodium hydroxide pretreatment did not remove phosphorous and other crystalline phases out of the biomass. However, sulfuric acid pretreatment of biomass greatly improved ash properties. It was also shown that enzymatic hydrolysis could have beneficial impact on ash properties because, during enzymatic hydrolysis, some phosphorous was leached out of the biomass.

Orientador: Mauro Mitsuuchi Tashima / Resumo: O modo como são dispostos os resíduos gerados pela indústria, pela agropecuária e pela sociedade gera uma preocupação crescente. Muitas pesquisas têm sido desenvolvidas com a finalidade de diminuir o impacto que estes causam a sociedade e ao meio ambiente. Diversos resíduos têm sido estudados como materiais cimentícios suplementares para substituição de parte da quantidade de cimento, contribuindo para a redução de áreas de aterro e também na diminuição da emissão de CO2 associada à produção de cimento Portland, que é responsável por cerca de 5% a 8% da emissão global de CO2. Um destes resíduos industriais é a cerâmica vermelha, proveniente do descarte de olarias. O objetivo geral dessa pesquisa é estudar a aplicação de resíduo cerâmico proveniente de olarias em misturas de solo-cimento para estabilização de um solo laterítico, avaliando a resistência à compressão, o efeito de expansão e contração, o potencial hidrogeniônico, a condutividade elétrica, a microestrutura e a proporção ideal de mistura (solo + resíduo cerâmico + cimento Portland). Os resultados mostram ganho de resistência e menor contração/expansão para as misturas com cimento, em relação ao solo puro. E que mesmo com a substituição de parte do cimento por resíduo cerâmico, a resistência praticamente não se altera, devido a reação pozolânica existente entre a cerâmica e o hidróxido de cálcio, o que é confirmado nos ensaios de pH e condutividade elétrica e por imagens obtidas por meio de microscopia eletrônica de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The waste generated by industry, agriculture and society is a growing concern. Much research has been carried out to reduce the impact on society and the environment. Several residues have been studied as supplementary cementitious materials to replace part of the amount of cement, contributing to the reduction of landfill areas and also to the reduction of CO2 emissions associated with the production of Portland cement, which accounts for about 5% of 8% of global CO2 emissions. One of these industrial wastes is red ceramics from the disposal of potteries. The general objective of this research is to study the application of different percentages of the mixture of ceramic residue with Portland cement in the stabilization of a lateritic soil, evaluating the compressive strength, expansion and contraction effect, permeability, hydrogenation potential, electrical conductivity, the microstructure and the ideal mixing ratio (soil + ceramic residue + Portland cement). The results show increased strength and lower contraction / expansion for cement additions, relative to pure soil. And even with the replacement of part of the cement by ceramic waste, the strenght is practically unchanged due to the pozzolanic reaction between the ceramic and the calcium hydroxide, which is confirmed in the pH and electrical conductivity tests and the images of scanning electron microscopy. / Mestre

[pt] O objetivo do presente estudo consistiu na obtenção, caracterização mecânica e química das fibras de bucha vegetal (Luffa cylindrica) utilizadas, e o emprego das mesmas como possível reforço de compósitos cimentícios. Inicialmente, as fibras de bucha foram encaminhadas à prensa mecânica para perder o seu formato cilíndrico, propiciando uma moldagem mais facilitada, dos posteriores compósitos. A partir daí, foram submetidas a ensaio de tração direta, dividindo-se entre filamento e tecido, difração de raios-x (DRX), espectroscopia de infravermelho (IV), microscopia eletrônica de varredura (MEV) e análise em microscópio digital, com posterior análise em software digital. A matriz foi dosada, respeitando uma substituição parcial de 50 porcento de cimento, por materiais pozolânicos, como 40 porcento de metacaulinita e 10 porcento de cinza volante, com o objetivo de diminuir a quantidade de Hidróxido de Cálcio (HC), produto oriundo da hidratação do cimento. Também foi utilizado superplasticante na confecção da pasta, para melhorar a fluidez e assegurar que toda a área do molde fosse preenchida, além de prover o encharcamento uniforme da fibra. A caracterização química matriz se deu através do ensaio de termogravimetria (TGA), o qual foi capaz de corroborar a baixa presença de HC, propiciando a incorporação de fibras vegetais nessa matriz. As propriedades mecânicas foram avaliadas a partir de ensaio de flow tabe, de resistência à compressão e à flexão. O composto com a matriz supracitada foi confeccionado com as fibras de bucha vegetal nas direções do carregamento e posteriormente encaminhados ao ensaio de flexão de três pontos. Para agregar valor à discussão, foi fabricado um compósito sanduíche com a fibra de sisal (Agave sisalana) em conjunto com a fibra de bucha. Os compósitos cimentícios reforçados por fibra de bucha, e o compósito sanduíche apresentaram valores de resistência 33 porcento maiores, em relação aos corpos de prova moldados apenas com a matriz (sem reforço). / [en] The objective of this study was to obtain, mechanical and chemical fibre characterization of Loofah (Luffa cylindrica) used, and the use of same as possible reinforcement of cementitious composites. Initially, Loofah fibres were forwarded to the mechanical press for losing your cylindrical format, providing a more facilitated, molding of composite posterior. From there, were subjected to direct tensile test, dividing her time between filament and fabric, x-ray diffraction (XRD), infrared spectroscopy (IV), scanning electron microscopy (SEM) and microscope analysis Digital, with further analysis in digital software. The array was dosed, respecting a partial substitution of 50 per cent cement, Pozzolanic materials, such as 40 per cent metacaulinite and 10 per cent fly ash, with the goal of reducing the amount of calcium hydroxide (CH), native of cement hydration product. Superplasticizer was also used in the making of the folder, to improve the fluidity and ensure that the entire area of the mold were filled equally, in addition to providing the drenching fiber uniform. Chemical characterization through array of Thermogravimetry (TGA), which was able to corroborate the low presence of CH, resulting in the incorporation of vegetable fibers in this array. The mechanical properties were evaluated from flow tabe test, compression and flexural strenght. The compound with the above-mentioned matrix was made with Loofah fibres in the directions of loading and subsequently forwarded to the three-point flexural test. To add value to the discussion, made a sandwich composite with sisal fiber (Agave sisalana) in conjunction with the Loofah fiber. The cementitious composites reinforced by loofah fiber, and sandwich composite presented values of maximum 33 per cent larger in relation to specimens only molded array (no reinforcement), although it is not an improvement as significant as found in other synthetic or natural fibers, already studied and some in use by industry.

No description available.

La présente étude vise à valoriser des résidus agroindustriels comme matériaux pour l’habitat et la construction. Dans ce contexte, les travaux de recherche s’articulent autour de deux axes majeurs : le développement d’un liant alternatif et l’élaboration de matériaux composites à partir de ce liant alternatif et des matériaux végétaux. Deux liants composés utilisant des cendres de bagasse, nommés cendres de bagasse-chaux et ciment-cendres de bagasse ont été étudiés. A partir de ces liants composés, deux types de matériaux composites incluant des matériaux végétaux ont été élaborés : un composite incorporant des granulats de bagasse et de coco et un autre renforcé par des pulpes d’eucalyptus. Les propriétés physiques, chimiques, mécaniques et hydriques de ces matériaux ont été déterminées. Les résultats obtenus montrent que la calcination des cendres de bagasse à 600°C et la sélection des particules de taille inférieure à un diamètre seuil compris entre 45 et 63µm augmentent sa réactivité. Le liant composé cendres de bagasse-chaux est susceptible de développer une résistance à la compression de l’ordre de 39MPa à 28 jours, une valeur supérieure à celle des liants composés matériaux pouzzolaniques-chaux étudiés dans la littérature. Grace à sa faible alcalinité, ce liant composé préserve mieux les matériaux végétaux vis à vis de leur minéralisation et leur fragilisation comparativement au liant à base de ciment. L’incorporation de pulpes cellulosiques dans le liant composé cendres de bagasse-chaux permet d’obtenir des matériaux composites ayant des propriétés à la flexion comparables à celles d’un composite ciment-pulpes cellulosiques. / The present study aims to add value to agroindustrial residues as housing and building materials. In this context, the research works revolve around two main lines: the development of an alternative binder using agroindustrial residues and the production of composite materials from this alternative binder and plant resources. Two composed binder using bagasse ash, named bagasse ash lime and cement-bagasse ash, were optimised and produced. Using these composed binder, two kinds of composite materials including plant resources were produced: one composite developed with vegetable aggregates and another one reinforced with eucalyptus pulps. The physical, chemical, mechanical and hydric properties of these materials were investigated. The results show that the bagasse ash recalcination at 600 °C and the selection of the particles under a diameter limit (between 45 and 63 µm) improve its reactivity. Blended with slaked lime, the composed binder obtained with these parameters is likely to develop a compressive strength higher than 39 MPa at 28 days; this value is higher than the compressive strength of pouzzolanic material and lime based binder studied in the literature. In addition, due to the lower alkalinity of the interstitial solution of this composed binder, related to the lime consumption by the pouzzolanic material, it better protects vegetable materials from mineralization than the binders based on Portland cement. The incorporation of the cellulosic pulps in the composed binder lime-bagasse ash produces composite materials with a similar flexural behaviour as a composite made with cement and cellulosic pulp.

[ES] Una alternativa para reducir el consumo de materias primas y los impactos ambientales derivados del cemento Portland es la sustitución parcial del clínker por adiciones minerales de subproductos agroindustriales. El objetivo de este trabajo fue investigar los efectos de la extracción de potasio sobre la reactividad de las biopuzolanas a partir de cenizas puras de caña de azúcar y caña energética, y evaluar las ganancias ambientales potenciales en compuestos de cemento Portland, buscando producir cenizas reactivas y sostenibles, y potasio para su aplicación como fertilizante. La caña energética y la caña de azúcar se caracterizaron morfológicamente mediante microscopio electrónico de barrido y EDS, se analizó el suelo recolectado durante la extracción de ambas variedades. Ambas cañas fueron calcinadas a una temperatura de 600 °C con una velocidad de 4 °C/min y un tiempo de exposición de 120 min. Las cenizas fueron lavadas para la extracción de potasio, cloro y azufre, y molidas para obtener el mismo rango granulométrico, luego se realizó el análisis de la solución extraída del lavado, y, por otra parte, sobre las cenizas se llevaron a cabo los análisis de masa específica real, granulometría, fluorescencia de rayos X, pérdida al fuego, difracción de rayos X, termogravimetría, microscopía electrónica de barrido con EDS, y determinación de sílices amorfa y cristalina. En pastas de hidróxido de calcio y puzolanas se realizó análisis de fijación de cal por termogravimetría, microscopía electrónica de barrido con EDS, evaluación de reactividad puzolánica por conductividad y pH, y método de Frattini. En las pastas de puzolanas y cemento se realizó la prueba de porosidad por intrusión de mercurio. Se evaluó la influencia de las cenizas y humo de sílice en el comportamiento de los morteros de cemento Portland, con ensayos de masa específica, absorción de agua, porosidad aparente, resistencia a la compresión y carbonatación acelerada. Se utilizó la técnica de Evaluación del Ciclo de Vida para evaluar los impactos ambientales potenciales de los morteros con reemplazo parcial de ceniza de caña energética, de caña de azúcar y humo de sílice en comparación con el mortero de referencia (sin reemplazos). La quema de caña energética genera un 78% más de ceniza en comparación con la caña de azúcar. Las cenizas de hoja de la caña energética presentaron mayor cantidad de sílice que las de caña de azúcar; por otro lado, los tallos presentaron un alto contenido de potasio. El análisis de la solución de lavado de ceniza indicó la posibilidad de utilizar esta solución en fertirrigación debido a los altos valores de potasio y azufre en el agua. El humo de sílice, la ceniza de paja de caña de azúcar, la ceniza de paja de caña energética y la mezcla de cenizas de caña energética (tallo y paja) fueron las muestras que presentaron alta puzolanicidad. Los morteros con sustitución del 10% de cenizas, fueron los que presentaron mejores resultados en cuanto a resistencia mecánica. En general, la sustitución de contenidos superiores al 10% de ambas cenizas mejora considerablemente el comportamiento ambiental de los morteros, debido al menor consumo de cemento, y a la generación de los subproductos de la extracción de sacarosa, (como el residuo filtrado y vinaza) y el potasio extraído del lavado de las cenizas, que evitan la producción de agroquímicos para la agricultura. Teniendo en cuenta el comportamiento ambiental y la resistencia a la compresión, los morteros con mejores resultados son aquellos con un 10% de ceniza de caña energética, ya que alcanzan los valores más altos de resistencia a la compresión y buenos valores de desempeño ambiental. Por lo tanto, la ceniza de la caña de azúcar y de la caña energética se pueden utilizar para su incorporación en materiales cementantes, especialmente la ceniza de caña energética. Sin embargo, el potasio y el cloro deben extraerse hasta que estén dentro de los niveles aceptables para su uso en compuestos de cemento. / [CA] L'alternativa per a reduir el consum de matèries primeres i els impactes que origina la producció de ciment Pòrtland implicaria substituir parcialment el clínquer per minerals obtinguts de subproductes agroindustrials. L'objectiu d'aquest treball és investigar els efectes de l'extracció del potassi en la reactivitat de les bioputzolanes, a partir de les cendres de la canya de sucre i de la canya energètica, i a més a més avaluar els beneficis ambientals com a component del ciment Pòrtland. La finalitat seria produir cendres reactives més sostenibles que podran ser utilitzades com a putzolanes, així com potassi com a fertilitzant. La canya de sucre i la canya energètica es caracteritzaren morfològicament mitjançant microscòpia electrònica de rastreig amb espectroscòpia d'energia dispersiva de raigs X, i es va analitzar el sòl després de la recol·lecció de les plantes. Ambdues canyes foren calcinades a 600¿°C de temperatura, a una velocitat d'escalfament de 4¿°C/min durant un temps màxim d'exposició de 120 minuts. Després de la calcinació, les cendres foren rentades per a extraure el potassi, el clor i el sofre i a continuació foren moltes fins a obtindre la granulometria adequada. Finalment, es va fer l'anàlisi de la solució aquosa del rentat, i diferents anàlisis de les cendres: massa específica real, granulometria làser, fluorescència de raigs X, pèrdua al foc, difracció de raigs X, termogravimetria, microscòpia electrònica de rastreig amb espectroscòpia d'energia dispersiva de raigs X, avaluació de reactivitat putzolànica per conductivitat i pH, i mètode Frattini. Les pastes de putzolana i de ciment se'n van sotmetre a la prova de porositat per intrusió de mercuri. Es va avaluar com influeix la cendra de la canya de sucre, la cendra de la canya energètica i el fum de sílice en els morters de ciment Pòrtland, amb assajos de massa específica, absorció d'aigua, porositat aparent, resistència a la compressió i carbonatació accelerada. La tècnica d'Avaluació del Cicle de Vida, va ser utilitzada per a valorar els impactes ambientals possibles dels morters amb substitució parcial de cendra de canya de sucre, cendra de canya energètica i fum de sílice i comparar-los amb els morters de referència (sense reemplaçaments). La canya energètica genera un 78% més de cendra per hectàrea que la canya de sucre tradicional, per altra banda, les cendres de les fulles de la canya energètica tenen un major contingut de sílice i la tija una gran quantitat de potassi. Els resultats de l'anàlisi de les solucions de les cendres rentades, ens indiquen que és possible utilitzar aquesta solució en fertirrigació per l'alt contingut en potassi i sofre. El fum de sílice, la cendra de la palla de la canya de sucre, la de la palla de canya energètica i LA de la mescla de canya energètica (tija i palla) foren les mostres amb millors resultats de reactivitat putzolànica. Els morters substituïts amb un 10% de cendra de canya de sucre i de cendra de canya energètica són els que presentaren millors resultats de resistència mecànica. En general, amb substitucions superiors al 10% de les cendres de canya de sucre i de canya energètica millora considerablement el comportament ambiental dels morters, gràcies a un menor consum de ciment, i a la generació de subproductes de l'extracció de sacarosa (com residus de filtres i vinassa), i del potassi obtingut de rentar les cendres que eviten la producció de productes químics per a l'agricultura. Si tenim en compte el comportament ambiental i la resistència a la compressió, els morters amb un 10% de cendra de canya energètica són els que presenten millors resultats, ja que registren els valors més alts a la compressió. En resum, podem afirmar que les cendres de la canya de sucre i de la canya energètica poden ser utilitzades per a afegir-les als materials cimentants, especialment, la cendra de canya energètica, sempre que els nivells de potassi i clor estiguen dins dels nivells permesos per al seu ús en el ciment. / [EN] An alternative to reduce the consumption of raw materials and the environmental impacts arising from the production of Portland cement is the partial replacement of clinker by mineral additions using agro-industrial by-products. The present research aimed to investigate the effects of potassium extraction on the reactivity of biopozzolans from from sugarcane and energy cane, and to evaluate the potential environmental gains of its use in Portland cement composites, seeking to produce reactive and sustainable ash that can be used as pozzolan and potassium for application as a fertilizer. Energy cane and sugar cane were morphologically characterized using a scanning electron microscope and X-ray energy dispersive spectroscopy, and the soil ,in which both varieties grew, analyzed. Both canes were calcined at a temperature of600 °C with a heating rate of 4 °C/min and a maximum exposure time of 120 min. After burning, the ashes were washed for the extraction of potassium, chlorine and sulfur and, then ground to obtain the same granulometric range; the analysis of the solution extracted from the washing was carried out, and, for the obtained ashes, real specific mass, laser granulometry, X-ray fluorescence, loss on fire, X-ray diffraction, thermogravimetry, scanning electron microscopy with X-ray energy dispersive spectroscopy and determination of amorphous and crystalline silica were carried out. In calcium hydroxide/ash pastes, the lime fixation analysis by thermogravimetry, scanning electron microscopy with X-ray energy dispersive spectroscopy, pozzolanic reactivity evaluation by conductivity and pH, and Frattini method were performed. In cement/ash pastes, the porosity test by mercury intrusion was carried out. The influence of energy cane ash, sugar cane and silica fume on the performance of Portland cement mortars was evaluated, by means specific mass, water absorption, apparent porosity, compressive strength and accelerated carbonation tests. The Life Cycle Analysis technique was used to assess the potential environmental impacts of mortars with partial replacement of energy cane ash, sugar cane ash and silica fume compared to the reference mortar (without replacements). The burning of energy cane generates 78% more ash per hectare compared to conventional sugarcane, the leaf ashes of the energy cane had a higher amount of silica than the sugar cane one; on the other hand, the stalks showed high potassium content. The analysis of the ash washing solution indicated the possibility of using this solution in fertigation due to the high values of potassium and sulfur that were solubilized in the water. Silica fume, sugar cane straw, energy cane straw, and the mixture of energy cane (stem and straw) were the ashes that showed high pozzolanicity. The mortars with replacement of 10% of sugarcane ash, and 10% of energy cane, were the ones that presented the best results in terms of mechanical strength. In general, the substitution of contents above 10% of sugarcane and energy cane ashes improves the environmental performance of mortars considerably, due to the lower consumption of cement, the co-products generated in the extraction of sucrose, such as filter and vinasse, and the potassium extracted from washing the ash, which avoid the production of agrochemicals for agriculture. Taking into account environmental performance and compressive strength, the mortars with the best results are those with 10% energy cane ash, as they achieve the highest compressive strength and good environmental performance values. Thus, ashes from sugarcane and energy cane can be used for incorporation into cementitious composites, especially energy cane ash. However, potassium and chlorine must be extracted until they are within acceptable levels for the use of ashes in cementitious composites. / Pitolli Lyra, G. (2023). Aplicação das cinzas da indústria sucroalcooleira como biopozolanas e Kfertilizante: cana-de-açúcar e cana-energia [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/193853