Ornamental Stones

Abstract

RESUMO Apesar de as atividades minerárias serem fundamentais para a economia de diversos países, inclusive o Brasil, seu desenvolvimento não se dá sem que haja algum tipo de degradação ambiental. Os recursos minerais não são recursos renováveis e, portanto, uma vez extraídos, não podem ser substituídos, ou seja, é necessário que sejam utilizados de forma correta e responsável, levando em consideração o de-senvolvimento sustentável. Portanto, dentre outros aspectos, é necessário que as minerações antevejam o tratamento e a disposição dos resíduos gerados ou até mesmo a sua devolução ao meio ambiente. Assim, o objetivo principal deste trabalho é apresentar os diferentes tipos de lavras de rochas ornamen-tais, seus métodos e suas implicações sobre o meio ambiente. Ao longo do trabalho, são apresentados os principais impactos ambientais causados pelas minerações de rochas ornamentais, bem como a importância da recuperação das áreas degradadas por elas. Um melhor planejamento das extrações de rochas ornamentais definiria com maior precisão a viabilidade econômica do empreendimento e diminuiria os impactos ambientais negativos. Além disso, o fim das irregularidades seria possível com a intensificação das ações de políticas públicas, do monitoramento e da fiscalização. Palavras-chave: rocha ornamental; impactos ambientais; comunidade local; recuperação das áreas degradadas.

Harmonised Classification of the Causes of Defects in a Global Inspection System: Proposed Methodology and Analysis of Fieldwork Data

“…The sensitiveness of natural stone to environmental conditions and application specificities, combined with carelessness while prescribing this type of material and focusing more on aesthetics than on other properties, are the probable reasons for the higher prevalence of such a cause in natural stone claddings. Amaral et al [73] highlight that inadequate material selection of ornamental stones is a very common cause of defects. Lopez-Arce et al [74], while studying the extensive degradation at Bonaval Monastery in Spain, concluded that the extensive salt weathering resulted from the use of sulphate-bearing mortars combined with magnesium in the dolomite stone, magnesite of the plaster mortar and Mg-rich aggregate embedded in the bedding mortar, highlighting the importance of compatibility between materials.…”

Durability of Stone Cladding in Buildings: A Case Study of Marble Slabs Affected by Bowing

“…However, the test equipment did not allow direct measurements of the fundamental resonance frequency. Therefore, the dynamic modulus of elasticity was determined through the use of sound wave propagation velocities obtained from ultrasound tests performed on four flexural test specimens with bowing, and using the Poisson coefficients range found in literature for calcite marbles (0.25 to 0.41 [9][10][11][12][13]).…”

“…Ssd is the design load or stress determined from the combinations defined in Eurocode 0 [33], i.e., the combination of the characteristic values of wind (Wk), calculated through Eurocode 1 [17], and the self-weight of the slabs (Gk), which is calculated through the average density of marble stone (2700 kg/m 3 ) found in literature [6,[9][10][11][12][13], acting simultaneously:…”

“…As mentioned before, bowing seems more frequent in marble cladding; therefore, it is important to know some properties of this type stone. According to scientific and technical literature [6,[9][10][11][12][13], the marble can be characterized as a metamorphic stone consisting essentially of calcite crystals (94% to 99%), or more rarely of dolomite crystals, and may contain other minerals in smaller quantities (mica, quartz, dolomite, graphite, among others). Most calcite marbles are white or approximately white and may have veins given by the presence of other minerals (mentioned above).…”

“…Therefore, it is necessary to characterize their properties experimentally on a case-by-case basis. However, some mean values for the properties of white calcite marbles under initial conditions of use (such as "Carrara", "Évora/Estremoz", among others) can be found in literature [6,[9][10][11][12][13]: The occurrence of anomalies related to bowing in marble slabs suggest that there is a need to control the effects or to predict the tendency of bowing in real on-site cladding applications. This seems possible according to experimental investigations and the recently published European standard test method.…”