Chemical resistance of lime-based grouts for masonry strengthening

The stone masonry walls are present in many buildings and historical monuments, with undeniable asset value, but also in old buildings housing both in Portugal and in Europe. Most of these buildings in masonry are in certain cases in a high state of degradation needing urgent intervention. This requires the identification of deficiencies and the application of appropriate intervention techniques. One of the possible techniques for structural consolidation works of stone masonry walls is the injection of fluid mortars currently called grouts. The choice of grouts is very important with regard in particular to their chemical and physical properties. In this study, carried out under the Master of Chemical Engineering, two types of lime-based grouts were used, in order to evaluate and compare their chemical resistance due to the crystallization of soluble salts. One of the grouts is a pre-dosed blend commercially available, Mape-Antique I from company Mapei (CA), and the second grout is a mixture prepared in the laboratory (LB), comprising metakaolin, cement, hydrated lime, water and superplasticizer. With the purpose of evaluating the action of sulphates on these grouts, a series of samples underwent several wetting-drying cycles using two different temperatures, 20 °C and 50 °C. During the experiment it was determined the change of weight and compressive strength in the analyzed grouts, as well as the sulphate ion concentration and pH of the solution in which the samples were dipped. The commercial grout (CA) apparently has a greater chemical resistance to sulphates. However grout LB showed to have positive results in some parameters.

Evaluación de la eficiencia hidráulica, por presencia de plantas acuáticas en modelo físico: “Caso, Canal Jaboque, localidad Engativá, Bogotá D.C”

Bogotá (Colombia): Universidad de La Salle. Facultad de Ingeniería. Programa de Ingeniería Civil

Utilização de resíduos de catalisador (ECAT) e cinzas da casca de arroz (CCA) na elaboração de vidros silicatos soda-cal destinados a embalagem

Dissertação (Mestrado em Tecnologia Nuclear)

Estudo da incorporação da cal em composições binárias de solo-cimento para produção de tijolos maciços

The use of binders in the soil for the production of solid bricks is an old construction technique that has been used by several civilizations over time. At the same time, the need for environmental preservation and the tendency of scarcity of natural resources make the construction invest in researching new concepts, methods and materials for building systems for the sustainability of their economic activities. Thus arises the need to obtain building materials with low power consumption, capable of reducing the growing housing shortage of rural and urban population. Currently, research has been conducted on this topic to better understand the cementitious and pozzolanic reactions that occur in the formation of the microstructure of the soil-cement when added to other materials such as, for example, lime, and the relationship between microstructure and formed interfaces with the physical, mechanical and chemical analysis in compounds made from these ternary compositions. In this context, this study aimed to analyze the results of the influence of the incorporation of lime to the soil-cement to form a ternary mixture to produce soil-cement bricks and mortar without structural purposes. From the inclusion of contents of 6 %, 8 %, 10% and 12% lime to the soil, and soil-cement mixes in amounts of 2 %, 3 %, 4 % and 5 % were shaped-bodies of -cylindrical specimens to determine the optimum moisture content and maximum dry apparent specific weight. Then they were cured, and subjected to the tests of compressive strength, absorption and durability modified. Compositions obtained the best results in the tests performed on the bodies-of-proof cylindrical served as a parameter for molding of solid bricks, which underwent the same experimental methodology previously cited. The raw materials used, as well as compositions in which the bricks were molded solid, were characterized by physical and chemical tests, X-ray diffraction and scanning electron microscopy. The results obtained in the study indicate that the compositions studied, that showed the best results in terms of compressive strength, water absorption and durability ternary composition was soil, 10 % cement and 2 % lime

Efecto de la utilización de cal viva como aditivo sobre los parámteros de fermentación y la calidad nutricional en el ensilaje de pasto kikuyo (Pennisetum clandestinum), papa (Solanum tuberosum) y arveja (Pisum Sativum)

Tesis (Zootecnista). -- Universidad de La Salle. Facultad de Ciencias Agropecuarias. Programa de Zootecnia, 2013

Hidráulica nos jardins barrocos. Análise do uso da água nos jardins barrocos e discussão da influência de André Le Nôtre em Portugal

Mestrado em Arquitetura Paisagista - Instituto Superior de Agronomia - UL

Avaliação da condutividade hidráulica em áreas de recarga do Aquífero Guarani-microbacia hidrográfica do Córrego Espraiado (SP).

A condutividade hidráulica do solo saturado (Ksat) constitui parâmetro de grande relevância nos estudos de vulnerabilidade natural e, por consequência, na avaliação de riscos ambientais. Quando se trata de áreas frágeis, como são as áreas de recarga de aquíferos sedimentares, a avaliação da condutividade hidráulica torna-se ainda mais importante. Para esse estudo, selecionou-se uma área de recarga direta do Aquífero Guarani, caracterizada pela microbacia do córrego Espraiado, localizada na região de Ribeirão Preto (SP). Os principais solos dessa microbacia são Latossolo Vermelho Distrófico psamítico (LVdq) e Neossolo Quartzarênico Órtico (RQo). Para a avaliação da condutividade hidráulica (Ksat) desses solos utilizou- se o método da coluna saturada, cujos valores foram correlacionados com os de textura e estrutura do solo, considerados os parâmetros diretamente relacionados à Ksat. As correlações foram diretas entre os valores de Ksat e os de textura arenosa (areia). Já para a estrutura do solo, essa correlação ocorreu de forma indireta, indicando menor influência desse parâmetro sobre a condutividade hidráulica do solo saturado.

Optimización del pelado de maíz con cal a utilizarse como estrategia de descontaminación de fumonisinas

Objetivo: En este estudio, el proceso de pelado de maíz con cal(PPC) fue documentado y sus parámetros optimizados mediante un diseño experimental, con el fin de conseguir un pelado completo del maíz con el mínimo grado de contaminación con fumonisinas. La presencia de fumonisina B1 (FB1) en el maíz fue analizada mediante HPLC-RP-FLD. Metodología: Los experimentos se realizaron a partir de un lote de maíz en grano seco conformado por submuestras provistas por agricultores seleccionados del cantón Nabón de la provincia del Azuay en base a un trabajo de investigación previo realizado por el proyecto VLIR-IUC, “Nutrición, Alimentación y Salud”. El diseño experimental fue divido en tres etapas: la caracterización de proceso, el mismo que se realizó mediante encuestas y observaciones in situ; pruebas de agotamiento de cal para el PPC, las que se realizaron partiendo de los datos recogidos en la primera etapa, y las pruebas de evaluación del PPC en la reducción de fumonisinas B1. Resultados y conclusiones: Se observó que, independiente de la concentración de cal utilizada, la etapa de pelado produjo una reducción de 8.73 veces la concentración de FB1 del maíz crudo (P=0.030), y que el maíz pelado y cocinado presentó una reducción de 9.14 veces (P=0.019). Recomendaciones: Se recomienda continuar con la experimentación para elucidar si la reducción de FB1se debió al proceso mecánico de remoción de la cáscara, o a la transformación química en su forma hidrolizada, por lo que este trabajo podría considerarse como un estudio explorativo preliminar.

Influência da adição de cinza do bagaço de cana calcinada em sistemas de pastas para cimentação de poços petrolíferos

Cementing operation is one of the most important stages in the oil well drilling processes and has main function to form hydraulic seal between the various permeable zones traversed by the well. However, several problems may occur with the cement sheath, either during primary cementing or during the well production period. Cements low resistance can cause fissures in the cement sheath and compromise the mechanical integrity of the annular, resulting in contamination of groundwater and producing zones. Several researches show that biomass ash, in particular, those generated by the sugarcane industry have pozzolanic activity and can be added in the composition of the cementing slurries in diverse applications, providing improvements in mechanical properties, revenue and cement durability. Due to the importance of a low cost additive that increases the mechanical properties in a well cementing operations, this study aimed to potentiate the use of sugarcane bagasse ash as pozzolanic material, evaluate the mechanisms of action of this one on cement pastes properties and apply this material in systems slurries aimed to cementing a well with 800 m depth and geothermal gradient of 1.7 °F/100 ft, as much primary cementing operations as squeeze. To do this, the ash beneficiation methods were realized through the processes of grinding, sifting and reburning (calcination) and then characterization by X-ray fluorescence, XRD, TG / DTG, specific surface area, particle size distribution by laser diffraction and mass specific. Moreover, the ash pozzolanic activity added to the cement at concentrations of 0%, 20% and 40% BWOC was evaluated by pozzolanic activity index with lime and with Portland cement. The evaluation of the pozzolanic activity by XRD, TG / DTG and compressive strength confirmed the ash reactivity and indicated that the addition of 20% in the composition of cement slurries produces improvement 34% in the mechanical properties of the slurry cured. Cement slurries properties evaluated by rheological measurements, fluid loss, free fluid, slurry sedimentation, thickening time and sonic strength (UCA) were satisfactory and showed the viability of using the sugarcane ash in cement slurries composition for well cementing

Distribuição e propriedade hidráulica dos solos da várzea de curuai, Pará

Dissertação (mestrado)—Universidade de Brasília, Instituto de Geociências, 2016.

Cana + cal + uréia para alimentação do gado na seca.

2016

Structural Health Monitoring Inside Concrete and Grout Using the Wireless Identification and Sensing Platform (WISP)

This research investigates the implementation of battery-less RFID sensing platforms inside lossy media, such as, concrete and grout. Both concrete and novel grouts can be used for nuclear plant decommissioning as part of the U.S. Department of Energy’s (DOE’s) cleanup projects. Our research examines the following: (1) material characterization, (2) analytical modeling of transmission and propagation losses inside lossy media, (3) maximum operational range of RFID wireless sensors embedded inside concrete and grout, and (4) best positioning of antennas for achieving longer communication range between RFID antennas and wireless sensors. Our research uses the battery-less Wireless Identification and Sensing Platform (WISP) which can be used to monitor temperature, and humidity inside complex materials. By using a commercial Agilent open-ended coaxial probe (HP8570B), the measurements of the dielectric permittivity of concrete and grout are performed. Subsequently, the measured complex permittivity is used to formulate analytical Debye models. Also, the transmission and propagation losses of a uniform plane wave inside grout are calculated. Our results show that wireless sensors will perform better in concrete than grout. In addition, the maximum axial and radial ranges for WISP are experimentally determined. Our work illustrates the feasibility of battery-less wireless sensors that are embedded inside concrete and grout. Also, our work provides information that can be used to optimize the power management, sampling rate, and antenna design of such sensors.