Renata Adamcova - Academia.edu (original) (raw)

Papers by Renata Adamcova

Coatings

The efficiency of three commercial hydrophobic coatings applied on two types of sandstones was su... more The efficiency of three commercial hydrophobic coatings applied on two types of sandstones was subjected to the tests of water absorption by capillarity, water absorption by complete immersion, and frost resistance. Two days of the curing time of coatings on samples were chosen for the laboratory tests. The effects of the used coatings were different (ambiguous). Two coatings proved their effectiveness and thus, relevance of their use, but different coatings were effective on each type of sandstone. The coating F showed the best efficiency for the Hořice sandstone and coating A for the Malé Skalky sandstone. The third testing coating H was ineffective on both types of sandstone. The water absorption tests by capillarity showed a loss of the coating effectiveness over time. By completely immersing the samples in water, all three coatings lost their effectiveness and the hydrophobic effects disappeared. Applied protective coatings helped to preserve the frost resistance of the Hořice ...

Materials

Natural stone constructions for the protection of slopes, banks and riverbeds are widely used in ... more Natural stone constructions for the protection of slopes, banks and riverbeds are widely used in infrastructure engineering. These structures are made of stacked natural stones, which can be placed loosely on top of each other. Additionally, their bond behavior can be improved by using concrete mortar to fill the joints between the stones. Although such structures are now widely used, there is still a need for research concerning their inner stability and the structural design of such protective stone structures. In this study, experimentally, investigations were made to determine the force transmission and the interaction between rock and concrete mortar by deriving characteristic values of the adhesion strength and friction angle at different scales. A method for the determination of shear parameters from direct shear testing is used, considering the interaction between vertical and horizontal forces in the joint. In the course of these investigations, the roughness of the rock su...

Acta Geologica Slovaca, Jun 15, 2021

The application of protective coatings can significantly influence the essential physical propert... more The application of protective coatings can significantly influence the essential physical properties of rocks used in building and decorative industries. This paper presents the results of laboratory tests demonstrating the positive effect of the protective coating Antipluviol S applied on a tuff from Tuscany in Italy, which is a weak volcanic rock of a very low strength and very high porosity. The efficiency of the coating was measured by absorption tests, standard uniaxial compressive strength tests and cyclic frost resistance tests. After the coating application, the water absorption decreased from 39.1% to 31.3% by total rock immersion at atmospheric pressure conditions. The water absorption only by capillary suction showed much higher efficiency of the coating. The change in the rock strength, resulting from the coating application, was less pronounced; the mean values rose from 5.8 to 6.8 MPa (17.2% increase). For all strength values are quite similar in both treated and untreated groups, as well as scattered within the groups, no relevance to the coating impact could be confirmed. But, even such a slight improvement of the monitored physical parameters has the effect of slowing down the rock's weathering. This was proven by the results of the frost resistance test. Coated samples withstood all the standard 25 freeze-thaw cycles, whereas untreated samples began to disintegrate after the 17th test cycle. These findings can help the maintenance of the famous historic architecture of picturesque tuff towns of Tuscany suffering from weathering, and contribute to the preservation of the cultural heritage. On the other hand, they showed how important such tests are when considering building stone import.

The most significant factors affecting the results of Uniaxial Compressive Strength (UCS) test ar... more The most significant factors affecting the results of Uniaxial Compressive Strength (UCS) test are the size, slenderness ratio h/d (ratio of height to diameter), and the shape of the rock specimen. The proposed experimental study shows the variable impact of these parameters on UCS values by implementing several lithological types. Standard strength tests were performed on four lithological types: granodiorite, limestone, sandstone and andesite. Cylindric and cube-shaped test specimens of different sizes were prepared from each rock. Cylindric specimens with diameter 20 mm, 35 mm, 50 mm and 70 mm with height to diameter ratio of 1:1 and 2:1, and cubic and prismatic specimens with an edge dimension of 50 mm were tested and analyzed. Obtained results of strength tests confirmed a high variability of current research opinions on how the size and shape of specimens influence the strength values of rocks. The study revealed the impossibility of conclusive correlations between the UCS and...

Im Rahmen von zwei internationalen Forschungsprojekten wurde die Grundwasserschutzfunktion einige... more Im Rahmen von zwei internationalen Forschungsprojekten wurde die Grundwasserschutzfunktion einiger typischen Boden aus Karstgebieten untersucht. In verkarsteten Karbonaten ist die Grundwasserstromungsgeschwindigkeit extrem hoch und das Grundwasser auserst verletzbar. Die Boden stellen oft die einzige Kontaminationsbarriere dar. Anhand einer komplexen interdisziplinaren Laboruntersuchung der gestorten und ungestorten Bodenproben aus Roschen wurde gepruft, ob und wie gut die Barrierefunktion gewahrleistet wird. Dabei spielt die Bodendurchlassigkeit eine entscheidende Rolle. Vier verschiedene Methoden wurden angewandt (Triaxialpermeameter, Oedometer, Bestimmung anhand von Korngrossenverteilung, Feldversuche), um moglichst reale Intervalle vom Durchlassigkeitsbeiwert kf zu ermitteln. Die Interpretation wird auf die Mineralogie und (semiquantitative) Tonmineralogie der Boden bezogen, die ebenfalls eine Abschatzung des Riickhaltevermogens erlauben. In der Slowakei konzentrierte sich die F...

The rock mass deterioration is caused by exogenous factors from which the main role play the temp... more The rock mass deterioration is caused by exogenous factors from which the main role play the temperature and moisture content. A monitoring system of the rock moisture content based on the transient Hot-ball method of measuring of the thermal conductivity of materials was installed on the Perún`s rock at the Spiš Castle. So called, hot ball method was used for the estimation of the water content in various depths inside the rock mass in order to assess its eff ect on the temperature penetration depth beneath the surface, which might control the volumetric change (dilation) of the rock cliff and its stability. The preliminary results showed relation between q/T m index and the precipitation registered by the nearby meteorological station. This dependence was manifested in the near subsurface parts of the rock face while the deeper sensors were not infl uenced. This suggests that the surface parts of the travertine rock body are more prone to the temperature dilation eff ects and therefore the thermal fl ux through the upper 40 cm of rock is faster than through the deeper parts.

Zosuvne lokality Svidnik (SK) a Klodne (pri meste Limanowa, PL) sa nachadzaju vo vonkajsom flysov... more Zosuvne lokality Svidnik (SK) a Klodne (pri meste Limanowa, PL) sa nachadzaju vo vonkajsom flysovom pasme Zapadných Karpat. Za ucelom výskumu významu obsahu ilovitej frakcie a ilových mineralov pre vznik zosuvov boli na oboch lokalitach odobrane vzorky jemnozrnných deluvialnych zemin z niekoľkých hĺbkových urovni zosuvov. Na výskume spolupracovali Universitat fur Bodenkultur Wien (BOKU), kde boli urobene zrnitostne a mineralogicke analýzy, a Univerzita Komenskeho v Bratislave (UK), kde boli vykonane smykove skusky. Zrnitostna analýza bola vykonana modernou kombinovanou skuskou – mokrým osievanim na sade sit až do priemeru 0,020 mm a naslednou sedimentacnou analýzou v pristroji Sedigraph, kde sa zmena hustoty suspenzie meria absorpciou prechadzajuceho RTG-luca pevnými fazami v suspenzii v rovine merania. Na klasifikaciu zemin boli standardne stanovene konzistencne medze - medza tekutosti (Casagrandeho metodou) a medza plasticity. Na stanovenie mineralneho zloženia bola použita RTG-di...

Carbonate rock aquifers are composed of water-soluble rocks where fractures can be widespread by ... more Carbonate rock aquifers are composed of water-soluble rocks where fractures can be widespread by karsting to sinkholes, caves or tunnels causing water that water and any accompaying pollutants move very rapidly. Therefore, groundwater is very suscesible to pollution in karst areas. Even some heavy metals can migrate to considerable distances through karst channels despite the buffering capacity of surrounding carbonates. soils are often the only cover of the carbonates and in that case the thicknes, the permaebility and sorption properties control the migration velocity of contaminants.

Presented paper brings infomation about the Slovak-Croatian scientific co-operation on a very new... more Presented paper brings infomation about the Slovak-Croatian scientific co-operation on a very new interdisciplinary project. In connection with the groundwater vulnerability mapping in karst areas, the aim of the study is to investigate the permeability and retention properties of fine-grained soils in brezovske karpaty Mts. and Slovensky Kras (Slovakia) and on the Istrian peninsula (Croatia).

Technology applied for revitalization of the Slnečné jazerá Lakes in Senec (town in western Slova... more Technology applied for revitalization of the Slnečné jazerá Lakes in Senec (town in western Slovakia) produced a temporary landfi ll of pumped and separated fi ne-grained bottom sediments. To minimize disposed waste, landfi lled sediments were analysed and some potential geotechnical and environmental applications were considered. Mineral composition was studied by the X-ray diff ractometry. Grain-size analyses and tests on Atterberg consistency limits allowed the engineering-geological classifi cation: sandy (clayey) silt sa(cl)Si according to EU standards or F3 and F5, symbols MS and MI, according to STN 72 1001. Other tests: moisture, consistency and compactibility; on compacted samples, dry bulk density, compressibility and hydraulic conductivity. Geochemical analyses included: soil reaction pH, cation exchange capacity (CEC), organic matter (C org) and carbonates. Dangerous substances were analysed earlier. Comparison with relevant technical standards and limits given by law fo...

Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the eng... more Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the engineering geological research of the clay in both, the natural and engineered barriers are summarized in the paper. The Szecseny Schlier from the Lucenec Formation is a potential sedimentary host rock for the DGR in Slovakia of favourable properties, similar to a natural clay barrier. It is a friable calcareous siltstone with intercalations of silty clay and fine-grained sandstone, of low hydraulic conductivity (k≅10-10 m.s -1 ) and acceptable uniaxial compessive strength (from 18.5 to 34.8 MPa). Engineering geological characterisation of this formation is based upon rock samples collected from boreholes and tested in the laboratory. Several deposits in Slovakia might offer suitable buffer/backfill material for engineered barriers of the DGR. Since 2003 five bentonite types have been studied, selected results of the engineering geological evaluation are discussed in this paper. Liquid lim...

Applied Sciences

Clinker production is very energy-intensive and responsible for releasing climate-relevant carbon... more Clinker production is very energy-intensive and responsible for releasing climate-relevant carbon dioxide (CO2) into the atmosphere, and the exploitation of aggregate for concrete results in a reduction in natural resources. This contrasts with infrastructure development, surging urbanization, and the demand for construction materials with increasing requirements in terms of durability and strength. A possible answer to this is eco-efficient, high-performance concrete. This article illustrates basic material investigations to both, using eco-friendly cement and recycled aggregate from tunneling to produce structural concrete and inner shell concrete, showing high impermeability and durability. By replacing energy- and CO2-intensive cement types by slag-pozzolanic cement (CEM V) and using recycled aggregate, a significant contribution to environmental sustainability can be provided while still meeting the material requirements to achieve a service lifetime for the tunnel structure of...

Instabile Hänge und andere risikorelevante natürliche Prozesse, 1996

Environmental Earth Sciences, 2003

With the use of the optimised three-step BCR sequential-extraction procedure it was possible to a... more With the use of the optimised three-step BCR sequential-extraction procedure it was possible to assess the mobility of selected elements in soil profiles from Croatian and Slovakian karst terrains. The soils in the Croatian karst were enriched in Cr, Ni, V, Mn, Cu, Cd and Mo, while soils from the Slovak Karst had high Pb and Zn concentrations. It was determined that the elements were most readily mobilised from the topsoil and the degree of mobility decreased with depth. Cr and Ni were mainly bound to the residual fraction, and Pb in the oxidisable fraction. Cu mobility was high in samples treated with agrochemicals throughout the soil profile.

The ruin of the medieval Sasov castle, a cultural heritage object in the Middle Slovakia, suffers... more The ruin of the medieval Sasov castle, a cultural heritage object in the Middle Slovakia, suffers from a strong deterioration. Besides the weathered binder, a reasonable part of the damages is caused by the intensive weathering of the building stone. The walls are built mainly of Neogene andesite, which is common in this area of the volcanic Stiavnicke Vrchy Mts. The sound rock is of dark grey colour, but most of the building stones have yellowishbrown coatings of iron oxyhydroxides on the surface and in the fissures. Highly macro-porous stones are most affected by the alteration. Weathering of the andesite was studied within the project VEGA 1/0413/09 of the Ministry of Education of the Slovak Republic. The X-ray diffractometry (XRD) of the powdered weathered building stone showed that the mineral assemblage is dominated by the plagioclase andesine (63 wt%) and the main alteration product smectite (up to 22 wt%), the rest are amorphous phases/volcanic glass (13 wt%), augite (1 wt%)...

Coatings

The efficiency of three commercial hydrophobic coatings applied on two types of sandstones was su... more The efficiency of three commercial hydrophobic coatings applied on two types of sandstones was subjected to the tests of water absorption by capillarity, water absorption by complete immersion, and frost resistance. Two days of the curing time of coatings on samples were chosen for the laboratory tests. The effects of the used coatings were different (ambiguous). Two coatings proved their effectiveness and thus, relevance of their use, but different coatings were effective on each type of sandstone. The coating F showed the best efficiency for the Hořice sandstone and coating A for the Malé Skalky sandstone. The third testing coating H was ineffective on both types of sandstone. The water absorption tests by capillarity showed a loss of the coating effectiveness over time. By completely immersing the samples in water, all three coatings lost their effectiveness and the hydrophobic effects disappeared. Applied protective coatings helped to preserve the frost resistance of the Hořice ...

Materials

Natural stone constructions for the protection of slopes, banks and riverbeds are widely used in ... more Natural stone constructions for the protection of slopes, banks and riverbeds are widely used in infrastructure engineering. These structures are made of stacked natural stones, which can be placed loosely on top of each other. Additionally, their bond behavior can be improved by using concrete mortar to fill the joints between the stones. Although such structures are now widely used, there is still a need for research concerning their inner stability and the structural design of such protective stone structures. In this study, experimentally, investigations were made to determine the force transmission and the interaction between rock and concrete mortar by deriving characteristic values of the adhesion strength and friction angle at different scales. A method for the determination of shear parameters from direct shear testing is used, considering the interaction between vertical and horizontal forces in the joint. In the course of these investigations, the roughness of the rock su...

Acta Geologica Slovaca, Jun 15, 2021

The application of protective coatings can significantly influence the essential physical propert... more The application of protective coatings can significantly influence the essential physical properties of rocks used in building and decorative industries. This paper presents the results of laboratory tests demonstrating the positive effect of the protective coating Antipluviol S applied on a tuff from Tuscany in Italy, which is a weak volcanic rock of a very low strength and very high porosity. The efficiency of the coating was measured by absorption tests, standard uniaxial compressive strength tests and cyclic frost resistance tests. After the coating application, the water absorption decreased from 39.1% to 31.3% by total rock immersion at atmospheric pressure conditions. The water absorption only by capillary suction showed much higher efficiency of the coating. The change in the rock strength, resulting from the coating application, was less pronounced; the mean values rose from 5.8 to 6.8 MPa (17.2% increase). For all strength values are quite similar in both treated and untreated groups, as well as scattered within the groups, no relevance to the coating impact could be confirmed. But, even such a slight improvement of the monitored physical parameters has the effect of slowing down the rock's weathering. This was proven by the results of the frost resistance test. Coated samples withstood all the standard 25 freeze-thaw cycles, whereas untreated samples began to disintegrate after the 17th test cycle. These findings can help the maintenance of the famous historic architecture of picturesque tuff towns of Tuscany suffering from weathering, and contribute to the preservation of the cultural heritage. On the other hand, they showed how important such tests are when considering building stone import.

The most significant factors affecting the results of Uniaxial Compressive Strength (UCS) test ar... more The most significant factors affecting the results of Uniaxial Compressive Strength (UCS) test are the size, slenderness ratio h/d (ratio of height to diameter), and the shape of the rock specimen. The proposed experimental study shows the variable impact of these parameters on UCS values by implementing several lithological types. Standard strength tests were performed on four lithological types: granodiorite, limestone, sandstone and andesite. Cylindric and cube-shaped test specimens of different sizes were prepared from each rock. Cylindric specimens with diameter 20 mm, 35 mm, 50 mm and 70 mm with height to diameter ratio of 1:1 and 2:1, and cubic and prismatic specimens with an edge dimension of 50 mm were tested and analyzed. Obtained results of strength tests confirmed a high variability of current research opinions on how the size and shape of specimens influence the strength values of rocks. The study revealed the impossibility of conclusive correlations between the UCS and...

Im Rahmen von zwei internationalen Forschungsprojekten wurde die Grundwasserschutzfunktion einige... more Im Rahmen von zwei internationalen Forschungsprojekten wurde die Grundwasserschutzfunktion einiger typischen Boden aus Karstgebieten untersucht. In verkarsteten Karbonaten ist die Grundwasserstromungsgeschwindigkeit extrem hoch und das Grundwasser auserst verletzbar. Die Boden stellen oft die einzige Kontaminationsbarriere dar. Anhand einer komplexen interdisziplinaren Laboruntersuchung der gestorten und ungestorten Bodenproben aus Roschen wurde gepruft, ob und wie gut die Barrierefunktion gewahrleistet wird. Dabei spielt die Bodendurchlassigkeit eine entscheidende Rolle. Vier verschiedene Methoden wurden angewandt (Triaxialpermeameter, Oedometer, Bestimmung anhand von Korngrossenverteilung, Feldversuche), um moglichst reale Intervalle vom Durchlassigkeitsbeiwert kf zu ermitteln. Die Interpretation wird auf die Mineralogie und (semiquantitative) Tonmineralogie der Boden bezogen, die ebenfalls eine Abschatzung des Riickhaltevermogens erlauben. In der Slowakei konzentrierte sich die F...

The rock mass deterioration is caused by exogenous factors from which the main role play the temp... more The rock mass deterioration is caused by exogenous factors from which the main role play the temperature and moisture content. A monitoring system of the rock moisture content based on the transient Hot-ball method of measuring of the thermal conductivity of materials was installed on the Perún`s rock at the Spiš Castle. So called, hot ball method was used for the estimation of the water content in various depths inside the rock mass in order to assess its eff ect on the temperature penetration depth beneath the surface, which might control the volumetric change (dilation) of the rock cliff and its stability. The preliminary results showed relation between q/T m index and the precipitation registered by the nearby meteorological station. This dependence was manifested in the near subsurface parts of the rock face while the deeper sensors were not infl uenced. This suggests that the surface parts of the travertine rock body are more prone to the temperature dilation eff ects and therefore the thermal fl ux through the upper 40 cm of rock is faster than through the deeper parts.

Zosuvne lokality Svidnik (SK) a Klodne (pri meste Limanowa, PL) sa nachadzaju vo vonkajsom flysov... more Zosuvne lokality Svidnik (SK) a Klodne (pri meste Limanowa, PL) sa nachadzaju vo vonkajsom flysovom pasme Zapadných Karpat. Za ucelom výskumu významu obsahu ilovitej frakcie a ilových mineralov pre vznik zosuvov boli na oboch lokalitach odobrane vzorky jemnozrnných deluvialnych zemin z niekoľkých hĺbkových urovni zosuvov. Na výskume spolupracovali Universitat fur Bodenkultur Wien (BOKU), kde boli urobene zrnitostne a mineralogicke analýzy, a Univerzita Komenskeho v Bratislave (UK), kde boli vykonane smykove skusky. Zrnitostna analýza bola vykonana modernou kombinovanou skuskou – mokrým osievanim na sade sit až do priemeru 0,020 mm a naslednou sedimentacnou analýzou v pristroji Sedigraph, kde sa zmena hustoty suspenzie meria absorpciou prechadzajuceho RTG-luca pevnými fazami v suspenzii v rovine merania. Na klasifikaciu zemin boli standardne stanovene konzistencne medze - medza tekutosti (Casagrandeho metodou) a medza plasticity. Na stanovenie mineralneho zloženia bola použita RTG-di...

Carbonate rock aquifers are composed of water-soluble rocks where fractures can be widespread by ... more Carbonate rock aquifers are composed of water-soluble rocks where fractures can be widespread by karsting to sinkholes, caves or tunnels causing water that water and any accompaying pollutants move very rapidly. Therefore, groundwater is very suscesible to pollution in karst areas. Even some heavy metals can migrate to considerable distances through karst channels despite the buffering capacity of surrounding carbonates. soils are often the only cover of the carbonates and in that case the thicknes, the permaebility and sorption properties control the migration velocity of contaminants.

Presented paper brings infomation about the Slovak-Croatian scientific co-operation on a very new... more Presented paper brings infomation about the Slovak-Croatian scientific co-operation on a very new interdisciplinary project. In connection with the groundwater vulnerability mapping in karst areas, the aim of the study is to investigate the permeability and retention properties of fine-grained soils in brezovske karpaty Mts. and Slovensky Kras (Slovakia) and on the Istrian peninsula (Croatia).

Technology applied for revitalization of the Slnečné jazerá Lakes in Senec (town in western Slova... more Technology applied for revitalization of the Slnečné jazerá Lakes in Senec (town in western Slovakia) produced a temporary landfi ll of pumped and separated fi ne-grained bottom sediments. To minimize disposed waste, landfi lled sediments were analysed and some potential geotechnical and environmental applications were considered. Mineral composition was studied by the X-ray diff ractometry. Grain-size analyses and tests on Atterberg consistency limits allowed the engineering-geological classifi cation: sandy (clayey) silt sa(cl)Si according to EU standards or F3 and F5, symbols MS and MI, according to STN 72 1001. Other tests: moisture, consistency and compactibility; on compacted samples, dry bulk density, compressibility and hydraulic conductivity. Geochemical analyses included: soil reaction pH, cation exchange capacity (CEC), organic matter (C org) and carbonates. Dangerous substances were analysed earlier. Comparison with relevant technical standards and limits given by law fo...

Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the eng... more Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the engineering geological research of the clay in both, the natural and engineered barriers are summarized in the paper. The Szecseny Schlier from the Lucenec Formation is a potential sedimentary host rock for the DGR in Slovakia of favourable properties, similar to a natural clay barrier. It is a friable calcareous siltstone with intercalations of silty clay and fine-grained sandstone, of low hydraulic conductivity (k≅10-10 m.s -1 ) and acceptable uniaxial compessive strength (from 18.5 to 34.8 MPa). Engineering geological characterisation of this formation is based upon rock samples collected from boreholes and tested in the laboratory. Several deposits in Slovakia might offer suitable buffer/backfill material for engineered barriers of the DGR. Since 2003 five bentonite types have been studied, selected results of the engineering geological evaluation are discussed in this paper. Liquid lim...

Applied Sciences

Clinker production is very energy-intensive and responsible for releasing climate-relevant carbon... more Clinker production is very energy-intensive and responsible for releasing climate-relevant carbon dioxide (CO2) into the atmosphere, and the exploitation of aggregate for concrete results in a reduction in natural resources. This contrasts with infrastructure development, surging urbanization, and the demand for construction materials with increasing requirements in terms of durability and strength. A possible answer to this is eco-efficient, high-performance concrete. This article illustrates basic material investigations to both, using eco-friendly cement and recycled aggregate from tunneling to produce structural concrete and inner shell concrete, showing high impermeability and durability. By replacing energy- and CO2-intensive cement types by slag-pozzolanic cement (CEM V) and using recycled aggregate, a significant contribution to environmental sustainability can be provided while still meeting the material requirements to achieve a service lifetime for the tunnel structure of...

Instabile Hänge und andere risikorelevante natürliche Prozesse, 1996

Environmental Earth Sciences, 2003

With the use of the optimised three-step BCR sequential-extraction procedure it was possible to a... more With the use of the optimised three-step BCR sequential-extraction procedure it was possible to assess the mobility of selected elements in soil profiles from Croatian and Slovakian karst terrains. The soils in the Croatian karst were enriched in Cr, Ni, V, Mn, Cu, Cd and Mo, while soils from the Slovak Karst had high Pb and Zn concentrations. It was determined that the elements were most readily mobilised from the topsoil and the degree of mobility decreased with depth. Cr and Ni were mainly bound to the residual fraction, and Pb in the oxidisable fraction. Cu mobility was high in samples treated with agrochemicals throughout the soil profile.

The ruin of the medieval Sasov castle, a cultural heritage object in the Middle Slovakia, suffers... more The ruin of the medieval Sasov castle, a cultural heritage object in the Middle Slovakia, suffers from a strong deterioration. Besides the weathered binder, a reasonable part of the damages is caused by the intensive weathering of the building stone. The walls are built mainly of Neogene andesite, which is common in this area of the volcanic Stiavnicke Vrchy Mts. The sound rock is of dark grey colour, but most of the building stones have yellowishbrown coatings of iron oxyhydroxides on the surface and in the fissures. Highly macro-porous stones are most affected by the alteration. Weathering of the andesite was studied within the project VEGA 1/0413/09 of the Ministry of Education of the Slovak Republic. The X-ray diffractometry (XRD) of the powdered weathered building stone showed that the mineral assemblage is dominated by the plagioclase andesine (63 wt%) and the main alteration product smectite (up to 22 wt%), the rest are amorphous phases/volcanic glass (13 wt%), augite (1 wt%)...