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Construction and Building Materials 04/2013; 41:868-878. · 1.83 Impact Factor
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ABSTRACT: One of the properties that makes marble such an excellent construction and ornamental material is its low porosity. It is
very difficult for water or decay agents to penetrate the internal structure of materials with no or few pores, so enhancing
the durability of these materials. However, environmental temperature fluctuations bring about significant physical changes
in marbles that result in an increase in porosity, due to the appearance of new microcracks and the expansion of existing
ones. These cracks offer new paths into the marble which make it easier for solutions containing pollutants to penetrate the
material. Thermal expansion tests were performed on three different types of marble known as White, Tranco, and Yellow Macael
(Almeria, Spain), after which an increase in porosity (from 17 to 73% depending on marble type) was observed, mainly due to
crack formation. The structural changes occurring during thermal expansion tests were more significant in the case of White
Macael samples, a fact that is not only related to its mineralogical composition but also to the morphology of the grains,
grain boundaries and crystal size. Our research suggests that thermally weathered White Macael marble could be more susceptible
to decay by other contaminant agents than Tranco or Yellow Macael. The use of hot-stage environmental scanning electron microscopy
is proposed as a valid tool for observing, both in situ and at high magnification, changes in the fracture system of building
stones induced by thermal stress.
KeywordsMarble–Microcracks–Thermal expansion anisotropy–Grain boundaries
Environmental earth sciences 05/2012; 62(7):1375-1386. · 1.06 Impact Factor
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ABSTRACT: In the article we study the variation of brick durability and, more specifically, its resistance to salt crystallisation produced
by changes in its microstructure during firing. For this purpose, the evolution of both mechanical and pore structure properties
are studied within a wide range of temperatures (700–1100∘C). An increase in the firing temperature produces a more homogeneous and resistant brick, measured using ultrasound velocity
and uniaxial compressive strength. This result is obtained thanks to the vitrification process and changes in the brick's
pore structure: larger, rounder pores, which are quantified by their roundness and fractal dimension. As a result of these
changes, an excellent durability is achieved in the bricks studied when fired at temperatures above 1000∘C. Considering that few differences are noted in pore structure and brick strength between 1000 and 1100∘C, the recommended firing temperature is, for raw materials with a similar composition and production process, 1000∘C, as this involves a lower production cost than firing at 1100∘C.
Materials and Structures 04/2012; 39(1):105-113. · 1.28 Impact Factor
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ABSTRACT: The sulfation of four types of calcitic and dolomitic lime mortars exposed to SO2 in the presence of particulate matter from diesel vehicle exhaust emissions has been investigated. The binders mineralogy
and mortars texture are the main factors influencing the formation of deleterious sulfate salts. The type of binder also influences
the pore size distribution and the total porosity of the mortars: for equal aggregate (quartz or dolomite), dolomitic lime
mortars have smaller pores and higher porosity than calcitic ones. During the first 24h exposure to SO2, calcitic lime mortars undergo a higher weight increase than dolomitic ones due to rapid formation of gypsum on their surface.
However, at the end of the sulfation test (10days), dolomitic mortars show a higher weight increase due to massive formation
of epsomite and gypsum, which is facilitated by their higher porosity and the high reactivity of Mg phases in the porous and
partially carbonated binder. Control samples (not covered with diesel particulate matter) also develop calcium and magnesium
sulfates upon long term exposure to SO2. This is due to the presence of uncarbonated Ca and Mg hydroxides that promote SO2 fixation as sulfates. However, the amount and size of sulfate crystals are significantly smaller than those observed on samples
covered with diesel particulate matter. These results show that diesel particulate matter enhances the sulfation of lime mortars
and demonstrate that sulfation of dolomitic lime is an important mechanism for the in situ formation of highly soluble and
deleterious hydrated magnesium sulfates (epsomite and hexahydrite). The use of dolomitic limes in the conservation of monuments
exposed to air pollution in urban environments may therefore pose a significant risk.
Environmental Geology 04/2012; 56(3):741-752. · 1.13 Impact Factor
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ABSTRACT: A common decay scenario in old and new buildings was simulated: the effects on masonry structures of salt efflorescence or
subefflorescence produced by the rise of saline solution. Eight different types of masonry wall each made up of a combination
of different construction materials (brick, calcarenite and four types of mortar were combined as follows: pure lime mortar,
mortar+air entraining agent, mortar+pozzolana, mortar+air entraining agent+pozzolana) have been tested. These materials
have different textures (strong anisotropy in brick, irregular-shaped pores in calcarenite, retraction fissures or rounded
pores in mortars which also show a reduction of porosity along the contact area with the stone), different hydric behaviours
(under total immersion brick+mortar specimens absorb water faster than calcarenite+mortar specimens) and different pore
size distribution (brick shows unimodal pore distribution, whereas calcarenite and mortars are bimodal). In the salt weathering
test, mortars interlayered with masonry blocks did not act as sacrificial layers. In fact, they allowed salts to rise through
them and crystallize on the brick or calcarenite pieces causing the masonry structure to decay. Only the addition of an air-entraining
agent partially hindered the capillary rise of the salt-laden solutions.
Environmental Geology 04/2012; 56(3):729-740. · 1.13 Impact Factor
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ABSTRACT: Ceramic fragments from the archaeological excavation of the Iberian–Roman city of Basti (Spain) were studied from a geochemical point of view and by applying a statistical tool to X-ray fluorescence data to discover similarities between ceramic materials. The analysis of these samples was completed by performing a mineralogical analysis, textural observation, and by characterizing the porous system and the colour of the pieces. Our results enabled us to identify the source area of the clayey raw material in the surroundings of Basti and to estimate the firing temperature of the ceramics. Differences in the chemistry were confirmed by characteristics of the pastes and the mineralogical composition of the pieces. Some samples show black cores, which would suggest the presence of organic matter in the raw material and fast firing of the ceramics. The main types of temper were quartz grains and gneiss fragments, although carbonate grains were also identified. Our evidence suggests that most of the samples were well fired. New silicate phases were found to be present in several samples. The mercury intrusion porosimetry verified and confirmed the firing temperature of non-carbonated samples. Colorimetry showed that the colour of the ceramics varied according to the amount of CaO that they contained.
Archaeometry 09/2010; 53(2):340 - 363. · 1.18 Impact Factor
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Applied Clay Science 01/2009; 46(3):231-240. · 2.47 Impact Factor
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ABSTRACT: Cited By (since 1996): 3, Export Date: 10 September 2012, Source: Scopus, CODEN: ACLSE, doi: 10.1016/j.clay.2009.08.007, Language of Original Document: English, Correspondence Address: Grifa, C.; Dipartimento di Studi Geologici e Ambientali, Università del Sannio, Benevento, Italy; email: celestino.grifa@unisannio.it, References: ASTM Specification D1140-92, (1992) Test Method for Amount of Materials Soils Finer than the No 200 (75 μm) Sieve, Philadelphia, PA;
Applied Clay Science 01/2009; 46(3):231-240. · 2.47 Impact Factor
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ABSTRACT: âSierra Elvira stoneâ is one of the ornamental building stones most widely used in the historical monuments of eastern Andalusia. A Liassic age limestone, it appears in the central section of the Baetic Mountains and more specifically in the Middle Subbaetic domain. While the most common variety is a crinoid limestone, a micritic limestone of the same age has also been quarried, albeit in much smaller quantities. These stones form very thick beds, up to nearly 5 m deep, that run in consistently parallel lines and have a dip angle that facilitates quarrying.
With petrographic, physical and mechanical properties that ensure stone strength and durability, it is a high quality building material suitable for both structural and ornamental purposes. These properties can be attributed to the minimal open porosity and concomitant excellent water resistance that characterize the stone, as well as to its high mechanical strength and low textural anisotropy, both elastic and mechanical. With such attributes, the stone can be successfully used for any number of purposes, including decorative stonework (portals, fountains, plinths), structural members (column shafts and bases) or urban curbing and paving. Intervention on Sierra de Elvira limestone structures should be limited to cleaning or repair, for consolidating or protective materials are scantly effective.
La âPiedra de Sierra Elviraâ constituye una de las piedras ornamentales más significativas del Patrimonio Arquitectónico de Andalucía Oriental. Es una roca caliza del Lias que aflora en el Subbético Medio del sector central de las Cordilleras Béticas. El litotipo más explotado es una caliza con crinoides, en bastante menor importancia se ha extraído también otra caliza micrítica de la misma edad. Los bancos son muy potentes, en algunos casos de más de 5 m, con un paralelismo constante y un buzamiento que favorece su explotación en los frentes de cantera.
Sus características petrográfica y físico-mecánica le confieren una calidad técnica y durabilidad muy notables para su utilización como material de construcción estructural y ornamental. Los principales parámetros que determinan estas cualidades son su mínima porosidad eficaz y asociado a ello sus excelentes propiedades hídricas, así como sus elevadas resistencias mecánicas y el bajo coeficiente de anisotropía textural, tanto elástico como mecánico. Este conjunto de características ha permitido su utilización en muy diversas funciones constructivas: en elementos decorativos (portadas, fuentes, zócalos), estructurales (columnas, basas) o en piezas del mobiliario urbano: bordillos, losas, casi siempre presentando un estado de conservación bastante aceptable. La intervención en elementos constructivos de esta piedra debe limitarse a su limpieza o reintegración, ya que no resulta suficientemente efectiva la aplicación de productos de consolidación o de protección.
Materiales de Construccion. 01/2008;
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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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Proceedings of the International Conference on Heritage, Weathering and Conservation, HWC 2006; 01/2006
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ABSTRACT: Conference code: 75464, Cited By (since 1996): 2, Export Date: 10 September 2012, Source: Scopus, Language of Original Document: English, Correspondence Address: Grifa, C.; Dipartimento di Scienze Delta Terra, Universita Federico II, Napoli, Italy, References: Aruga, R., The problem of multivariate classification of samples with radial (or V-shaped) chemical data (2003) Talanta, 60, pp. 937-944;
Proceedings of the International Conference on Heritage, Weathering and Conservation, HWC 2006, Madrid; 01/2006
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ABSTRACT: We deal with the textural aspects, porometry and hydric behaviour of combinations of building materials and their durability under attack by salt crystallisation and freezing. We selected 4 types of lime mortar (pure lime mortar, lime mortar + air-entraining agent, lime mortar + pozzolana and lime mortar + air-entraining agent + pozzolana) which were used in combination with either brick or calcare-nite stone. Lime mortars were chosen because they are compatible with traditional building materials, including the bricks and calcar-enites that were widely used in the historical buildings that make up our architectural heritage. There are more similarities between the pore size ranges in calcarenites and mortars than there are between those in bricks and mortars. In all cases, a fine layer of calcite micro-crystals develops at the contact surface between the mortar and the stone or brick. This is produced by the transformation of the port-landite, which concentrates in this area due to capillary moisture migration. This surface may on the one hand represent an obstacle to the flow of water between the different parts of the system formed by these materials, but on the other it may also favour greater adher-ence between the components, especially in the calcarenite + mortar combination, which proved to be the most resistant to deterioration in the freeze–thaw tests.
10/2005;
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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: We have studied the carbonation process in different types of mortars, with and without pozzolana or air-entraining additives, subject to a CO2-rich atmosphere and compared the results with those of similar naturally carbonated mortars. We used X-ray diffraction technique to demonstrate that high CO2 concentrations favour a faster, more complete carbonation process with 8 days being sufficient to convert portlandite into 90 wt.% calcite. Full carbonation, however, is not reached during the life-span of the tests, not even in forced carbonation experiments. This could be due to at least one of the following phenomena: a premature drying of samples during carbonation reaction, the temperature at which the carbonation process was carried out or the reduction of pore volume occupied by newly formed calcite crystals. This last option seems to be the least probable. We observed a more prolific development of calcite crystals in the pores and fissures through which the carbonic anhydride flows. Under natural conditions, carbonation is much slower and similar levels are not reached for 6 months. These differences suggest that the carbonation process is influenced by the amount of CO2 used.Both the mineralogy and texture of mortars vary depending on the type of additive used but the speed of the portlandite–calcite transformation does not change significantly. Pozzolana produces hydraulic mortars although the quantity of calcium aluminosilicate crystals is low. The air-entraining agent significantly alters the texture of the mortars creating rounded pores and eliminating or reducing the drying cracks.
Cement and Concrete Research.
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ABSTRACT: The paper studies the effect of additives such as calcite, dolomite and sodium chloride on the mineralogical–textural and physical–mechanical behaviour of solid bricks destined for use as new materials in the restoration of historic buildings. The behavioural differences between specimens with and without carbonates can be explained by the different evolution of texture and mineralogical composition developed during the firing process. Carbonates are shown to result in bricks with different mineralogy, depending on firing, but with a stable microstructure within a wide range of temperatures (800–1000 °C). This may be an advantage when manufacturing pottery but these pieces lack mechanical resistance to high temperatures. Salt partially modifies the mineralogy of the bricks, acting as a melting agent, especially at high firing temperatures, and giving rise to more resistant products which are suitable for restoration work.
Construction and Building Materials.
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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.
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ABSTRACT: One of the most commonly used marbles in Spain is “White Macael” marble, quarried in the Macael area of Almeria. Throughout Spanish history, White Macael has been in great demand as an ornamental stone and was used to build pieces of great importance and artistic beauty, such as the Fountain of Lions in the Alhambra (Granada).Over the centuries, such pieces have suffered from decay due to exposure to the elements, as has happened in many other marbles all over the world.The main purpose of this paper was to determine the durability of White Macael marble when subjected to changes in thermal conditions. It was observed that these changes in the presence of humidity were an important factor in marble decay. They produce a progressive loss of cohesion along grain boundaries and an increase in porosity, which are starting points for marble degradation and facilitate the development of other pathologies.
Engineering Geology. 115:209-216.
