Robert Wacha | Bundesdenkmalamt Österreich (original) (raw)
Address: Informations- und Weiterbildungszentrum Baudenkmalpflege - Kartause Mauerbach
A-3001 Mauerbach, Kartäuserplatz 2
Tel.: +43 1 979 88 08 DW 104
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Email: Robert.wacha@bda.at
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The method of slaking lime using baskets can be mostly found in manuscripts from the 19 th centur... more The method of slaking lime using baskets can be mostly found in manuscripts from the 19 th century and describes mainly an easy procedure for producing calcium hydroxide powder [1]. For this, small pieces of quicklime were put in wooden or iron baskets and immersed in water for a few seconds. To test this rather unconventional technique under field conditions a locally burned limestone was slaked in wicker and iron baskets according to the description of the historical manuals. Although the approach of using lime with very little water contradicts most modern conventions for producing durable and stable coatings, the " basket lime " showed surprisingly good workability in its practical application such as a thin lime coat. When the samples of the test fields were analysed, the microscopic and SEM images showed signs of a specific structure of shrinkage-cracks, which seem to have some, probably, positive effects on the material. The paper shows the first results of practical tests of producing and working with basket slaked lime and the experiences with this special technique.
Anhangband mit Fotos und Laborberichten (Auflösung Web)
Untersuchung zur Zusammensetzung und Rekonstruktion des mittelalterlichen Mauermörtels der Burgru... more Untersuchung zur Zusammensetzung und Rekonstruktion
des mittelalterlichen Mauermörtels der Burgruine Prandegg
durch den experimentellen Nachbrand von Donaukies als
historisches Ausgangsmaterial zur Baukalkherstellung (Auflösung Web)
Untersuchungen zur Sanierung und Pflege frei stehender historischer Granitbruchsteinmauern in der... more Untersuchungen zur Sanierung und Pflege frei stehender historischer
Granitbruchsteinmauern in der Ruinenpflege anhand der Burgruine
Prandegg unter besonderer Berücksichtigung materialtechnischer
Aspekte im Bereich der Fugensanierung (Bildauflösung web-reduziert)
Anwendung und Analyse zur historischen Technik des Heißkalkmörtels an der Sengstschmidkapelle in ... more Anwendung und Analyse zur historischen Technik des Heißkalkmörtels an der Sengstschmidkapelle in Laussa
Lime was aside from clay the main historic mortar material for castles in the northern part of up... more Lime was aside from clay the main historic mortar material for castles in the northern part of upper Austria. As there are no geological sources of limestone in the region, the question was how the necessary amounts of quicklime were produced and transported. As analyses of historic mortar samples at the castle ruin of Prandegg showed constant slight impurities of magnesia/silicium and non-burnable pebbles with glass-like surfaces were found in the cores of the ruin walls, the assumption came up that the source of the historic quicklime could be burned Danube pebbles. Danube gravel is a mixture of limestones and quartz pebbles, which could be able to cause the discovered hydraulic effects. So a complete reconstruction of the historic mortar of Prandegg was done by burning Danube river gravel again in an archeotechnical experiment. During the slakings all burned limestone pebbles turned completely into homogeneous lime putty. The reconstructed " Danube gravel lime " mortar was then laboratory confirmed as it showed aside from the magnesia and silica phases a general similarity to the historic mortar in its chemical and physical structure.
The method of slaking lime using baskets can be mostly found in manuscripts from the 19 th centur... more The method of slaking lime using baskets can be mostly found in manuscripts from the 19 th century and describes mainly an easy procedure for producing calcium hydroxide powder [1]. For this, small pieces of quicklime were put in wooden or iron baskets and immersed in water for a few seconds. To test this rather unconventional technique under field conditions a locally burned limestone was slaked in wicker and iron baskets according to the description of the historical manuals. Although the approach of using lime with very little water contradicts most modern conventions for producing durable and stable coatings, the " basket lime " showed surprisingly good workability in its practical application such as a thin lime coat. When the samples of the test fields were analysed, the microscopic and SEM images showed signs of a specific structure of shrinkage-cracks, which seem to have some, probably, positive effects on the material. The paper shows the first results of practical tests of producing and working with basket slaked lime and the experiences with this special technique.
Anhangband mit Fotos und Laborberichten (Auflösung Web)
Untersuchung zur Zusammensetzung und Rekonstruktion des mittelalterlichen Mauermörtels der Burgru... more Untersuchung zur Zusammensetzung und Rekonstruktion
des mittelalterlichen Mauermörtels der Burgruine Prandegg
durch den experimentellen Nachbrand von Donaukies als
historisches Ausgangsmaterial zur Baukalkherstellung (Auflösung Web)
Untersuchungen zur Sanierung und Pflege frei stehender historischer Granitbruchsteinmauern in der... more Untersuchungen zur Sanierung und Pflege frei stehender historischer
Granitbruchsteinmauern in der Ruinenpflege anhand der Burgruine
Prandegg unter besonderer Berücksichtigung materialtechnischer
Aspekte im Bereich der Fugensanierung (Bildauflösung web-reduziert)
Anwendung und Analyse zur historischen Technik des Heißkalkmörtels an der Sengstschmidkapelle in ... more Anwendung und Analyse zur historischen Technik des Heißkalkmörtels an der Sengstschmidkapelle in Laussa
Lime was aside from clay the main historic mortar material for castles in the northern part of up... more Lime was aside from clay the main historic mortar material for castles in the northern part of upper Austria. As there are no geological sources of limestone in the region, the question was how the necessary amounts of quicklime were produced and transported. As analyses of historic mortar samples at the castle ruin of Prandegg showed constant slight impurities of magnesia/silicium and non-burnable pebbles with glass-like surfaces were found in the cores of the ruin walls, the assumption came up that the source of the historic quicklime could be burned Danube pebbles. Danube gravel is a mixture of limestones and quartz pebbles, which could be able to cause the discovered hydraulic effects. So a complete reconstruction of the historic mortar of Prandegg was done by burning Danube river gravel again in an archeotechnical experiment. During the slakings all burned limestone pebbles turned completely into homogeneous lime putty. The reconstructed " Danube gravel lime " mortar was then laboratory confirmed as it showed aside from the magnesia and silica phases a general similarity to the historic mortar in its chemical and physical structure.