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ABSTRACT: Santa Pudia limestone, a biocalcarenite highly sensitive to decay, is one of the most commonly used building materials in historical monuments in the city of Granada, Spain. The compatibility between a variety of stone treatments (consolidants and/or water repellents) and this calcarenite was analyzed and the resulting improvement in durability assessed. To this end, a two-stage accelerated ageing process was implemented. In the first, freshly quarried, undamaged specimens were altered to resemble the weathered stone in buildings. The second was conducted after applying the various treatments to the artificially aged stone to test their effectiveness. While all the treatments studied (Tegosivin HL100, Silo 111, Estel 1100 and Tegovakon V) enhanced stone resistance to decay while barely affecting chromatic parameters, the most effective was Tegowakon V, as it provided the best results in the hydric tests on the limestone.
La calcarenita de Santa Pudia es uno de los materiales rocosos de construcción más empleados en las edificaciones monumentales de la ciudad de Granada (España). Se ha evaluado la compatibilidad de diversos productos de tratamiento (de consolidación y/o hidrofugación) con esta calcarenita y como son capaces de mejorar su durabilidad. Para ello, se han realizado dos fases de envejecimiento acelerado: la primera tenía el objetivo de acercar el material de cantera sin alterar (“sano”) a las condiciones reales del material puesto en obra y actualmente deteriorado; la segunda, efectuada después de aplicar los tratamientos sobre la calcarenita deteriorada, con el fin de determinar su grado de eficacia. Se ha podido comprobar que aunque, en general, todos los productos de tratamiento seleccionados (Tegosivin HL100, Silo 111, Estel 1100 y Tegovakon V) mejoran las propiedades del material frente al deterioro y apenas modifican sus parámetros cromáticos, el más eficaz es el Tegovakon V ya que es el que proporciona mejores resultados frente a los ensayos hídricos en este litotipo calcáreo.
Materiales de Construccion. 01/2008;
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ABSTRACT: We have studied the physical-mechanical behaviour of solid bricks treated with consolidants and/or water-repellents in accelerated aging tests to determine their durability. The bricks were manufactured with a quartz-rich clay lacking in carbonates to which was added small amounts of different additives (calcite, dolomite or sodium chloride). During the manufacturing process, we attempted to replicate solid bricks similar to those used in many Cultural Heritage buildings. We have concluded that silicon resin gives the best results, whatever the additive used, whereas acrylic resin gives the least satisfactory results.Se ha estudiado el comportamiento físico-mecánico de ladrillos macizos tratados con productos consolidantes y/o hidrofugantes frente a ensayos acelerados de alteración para evaluar su durabilidad. En la fabricación de las piezas cerámicas se ha utilizado un material arcilloso rico en cuarzo y sin carbonatos al que se han añadido pequeñas cantidades de distintos aditivos (calcita, dolomita o sal). En el proceso de elaboración se han intentado reproducir ladrillos macizos similares a los empleados en muchos edificios del Patrimonio Arquitectónico. Se concluye que el uso de resina de silicona proporciona los mejores resultados, cualquiera que sea el aditivo añadido, mientras que los resultados menos satisfactorios se han calculado cuando se ha empleado una resina acrílica.
Materiales de Construccion. 01/2003;
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ABSTRACT: The weathering of different brick samples ina range of aggressive environments has been studied.Brick samples were prepared using two clay types (fromGranada, Spain), different additives, and a range offiring temperatures (850–1100 C). The brickscompositional and textural characteristics wereevaluated using XRD, SEM, hydric tests and mercuryintrusion porosimetry (MIP). The samples weresubjected to accelerate aging, including wet-dry,freeze-thaw and salt crystallization cycles. The decayof the bricks in polluted atmospheres was simulated ina static chamber containing sulfur dioxide (SO2)at 25 C and 50% relative humidity. Samplesfired at 1000 C proved to be the most durable,with better hydric behavior (fast drying and slowwater absorption) and fewer micropores. However, theywere not suitable for salt-rich environments (badperformance in the salt decay test). Samples fired at850 C turned out to be more resistant to saltdecay, but they showed a poor hydric behavior (slowdrying and rapid water absorption) and littleresistance to freeze-thaw and wet-dry cycles. Samplesfired at 1100 C had good hydric behavior, theyperformed well in the salt decay test, but they didnot perform as well as the samples fired at1000 C in most accelerated aging tests. Gypsumformed on all the brick samples submitted to SO2atmosphere regardless exposure time (e.g. gypsumappears following just 24 h of exposure),composition, or firing temperature. Samples withdeposited particulate matter collected from vehicleexhausts (diesel, as well as leaded and non-leadedgasoline motor cars) resulted in the fastest gypsumdevelopment and greater abundance. On the other hand,the blank samples, and the samples withpollution-derived dust collected from historicalbuildings showed little gypsum development. Theimplications of these results in historicalbrick-building preservation in a range of aggressiveenvironments, and in polluted atmospheres inparticular, are discussed.
Water Air and Soil Pollution 01/2000; 119(1):191-207. · 1.63 Impact Factor
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ABSTRACT: Lime mortar has been used throughout history despite current substitution by hydraulic mortars (cements). The chemical composition of the lime used in its manufacture, however, is determined by local geology. In addition, the type of slaking, which depends on the amount of water used, gives rise to different types of lime. The result is that the behavior of lime mortar can vary depending on the composition and type of lime used. A three-way ANOVA analysis was carried out to determine the composition, type, and temporal evolution and the interactions of these three variables for evaluation of the characteristics of air lime mortars for their use in cultural heritage conservation projects.
Cement and Concrete Research.
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ABSTRACT: Mixtures of clays are often used in the manufacture of bricks, with distinct additives for diverse ends. The firing process, however, determines the final properties of the material. In this work, ultrasound and mechanical tests have been combined with a statistical tool, the analysis of variance (ANOVA), to analyse the mineralogical and physical characteristics of solid bricks manufactured from mixtures of local clays to which small amounts of additives have been included. They were then fired at different temperatures, ranging from 850 up to 1100°C. A new parameter, defined as the “resistance anisotropy” has been formulated to simplify the statistical interpretations. In addition, a two-way ANOVA interaction analysis has been used to evaluate the effect that selected factors (addition/absence of additives and firing temperature) have on the technical quality of bricks.
Ceramics International.
