Geology of Hungary

2019

Bull Eng Geol Environ

The durability of aggregates against salt weathering is calculated after five cycles of immersion in a magnesium sulfate solution followed by drying according to the relevant European standard (EN 1367-2: 2010). The aim of the study is to investigate the long-term durability of aggregates by increasing the number of cycles of the salt crystallization test from the standardized five to a maximum of 35. Three andesite types from Hungarian quarries were tested representing three different localities. The weight loss of the specimens was determined after every 5-cycle set. Results were documented for three size-fractions 10.0/11.2 mm, 11.2/ 14.0 mm and the 10.0/14.0 mm, respectively. Relationships between immersion-drying cycles and magnesium sulfate values were described by the Pearson-coefficient. According to the test results, the magnesium sulfate values followed linearly increasing tendencies in the course of the long-term salt crystallization tests. Parallel to the salt-weathering tests, the changes in the mechanical properties of the salt-attacked aggregates were also detected by micro-Deval tests (EN 1097-1: 2012). The changes in micro-Deval coefficients were calculated in the form of a decay factor as a function of sulfate cycles. The results suggest that the micro-Deval coefficient does not rise after a certain salt cycle; i.e. higher number of salt-crystallisation cycles does not necessarily reduce the micro-Deval coefficient of studied andesite lithologies.

“…1). All studied and quarried andesites were formed in the Miocene period (Haas 2013). The andesites represent three different lithotypes (Table 1).…”

Section: Methodsmentioning

confidence: 99%

Effects of long-term magnesium sulfate crystallisation tests on abrasion and durability of andesite aggregates

Czinder

2019

Bull Eng Geol Environ

“…The limestone is mostly derived from local sources, but lithotypes of distant quarries were also identified; thus high variations in lithology of limestone were observed. The prevailing types of limestone belong to the Miocene so-called porous limestone sequence of the larger area [12].…”

Section: Building Materialsmentioning

confidence: 99%

Characterization of Historic Binders and Stones of a Ruined Medieval Church (Hungary)

Kósa

Period. Polytech. Civil Eng.

2020

Construction materials of a partly ruined Medieval church of Central Hungary were studied in details to assess its conditions and to obtain information on the phases of construction. At first, digital images were taken to create a 3D model of the remaining walls. The material properties were measured in situ using non-destructive test methods. Strength parameters of stone and render were assessed by Schmidt hammer, while moisture content was measured by a portable moisture meter. According to lithological descriptions and thin-section analyses limestone prevail in the monument. The most common Miocene limestone is represented by various lithologies, such as cemented macro porous limestone, fine-grained porous limestone, oolitic limestone and bioclastic limestone. Mesozoic micritic well cemented limestone and Tertiary limonitic sandstone were also identified at the ruins. The most common weathering forms are selective dissolution, multiple flaking and biological colonisation. Renders used in the structure represents the long history of the structure from Medieval lime-based mortars to Portland cement containing latest applications. The former one is composed of quartz send in lime binder. According to Schmidt hammer tests, the rebound values of the replacement stone is higher than that of the original porous limestone. There is a distinct difference in the moisture content of the stone and render. Orientation/exposure of the wall also influences the moisture content. The gathered information allows for designing better repair methods and helps in the planning of the maintenance of the medieval stone heritage.

“…The generalized Hoek-Brown failure criterion (Hoek et al, 2002) was used to determine strength parameters of the rock mass. Altogether, 53 cylindrical test specimens were used for the tests.…”

Section: Engineering Geology and Slope Stability Analysismentioning

confidence: 99%

Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

Nat. Hazards Earth Syst. Sci.

Barsi

Bögöly

et al. 2018

Abstract. Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System) was used to collect images which were processed by Pix4D mapper (structure from motion technology) to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS) with the use of seven ground control points. The obtained digital surface model (DSM) was processed (vegetation removal) and the derived digital terrain model (DTM) allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method). Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE-WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS).