Umwelteigenschaften mineralischer Werkmörtel: Fid-Bau Portal

Umwelteigenschaften mineralischer Werkmörtel

Scherer, Christian

Mineralische Putz- und Mauermörtel sind bewährte Baustoffe, deren mechanische und baupraktische Eigenschaften eingehend untersucht sind. Über ihr ökologisches Verhalten unter realen Klimabedingungen ist jedoch wenig bekannt. In dieser Arbeit wird ein experimenteller Ansatz verfolgt, indem ein- und mehrlagige Putz- und Mauermörtelvarianten unterschiedlicher Zusammensetzung über drei Jahre gegenüber realen Klimaeinflüssen exponiert werden. Das bei Schlagregenereignissen von den Probekörpern ablaufende Regenwasser wird auf Summenparameter sowie anorganische und organische Inhaltsstoffe untersucht. Orientierend werden ausgewählte einlagige Varianten mittels etablierter Laborverfahren auf ihre Stofffreisetzung bei Beaufschlagung mit Wasser analysiert. Damit ergeben sich umfassende und systematische Erkenntnisse über das Auslaugverhalten von Inhaltsstoffen. Die orientierende Anwendung der Laborverfahren lässt erste Rückschlüsse darauf zu, inwieweit das Verhalten von beregneten Putz- und Mauermörteln unter Realbedingungen mit einfachen Laborverfahren abgebildet werden kann.

Mineral plasters and masonry mortars are proven building materials for thousands of years. Their mechanical properties and practical applications are examined in detail. The European Construction Products Directive (CPD) and the European Construction Products Regulation (CPR) define in addition to the traditional requirements for construction products (mechanical resistance and stability, safety in case of fire, safety in use, sound insulation, energy economy and heat retention), requirements for hygiene, health and the environment. So far, these properties have neither been studied nor evaluated. For studying the leaching of cement-based materials with water contact, established laboratory procedures and transfer functions to assess the environmental properties partly exist. The leaching of substances from masonry mortars under real climatic conditions has not been systematically studied yet. Validated laboratory methods, and modeling to estimate the ecological properties are not available up to now for mineral plasters and mortars. In the present study, test specimens, consisting of eight single-layer and seven multilayer masonry mortar variants, were exposed against real climate influences from 10/2006 to 10/2009. The climatic parameters were recorded throughout the duration of exposure and compared with the long-term average values. The run-off water from the test specimens was collected and analyzed for inorganic cations, inorganic and organic anions, as well as sum parameters. Plotting the cumulative releases to the cumulative amount of wind-driven rain, four different release patterns could be found. These release patterns depended on the properties of the leached substances rather than on the formulation of the mortar. The formulations and the assembly of the test specimens influenced the slopes and the step heights of the cumulative release curves. At the beginning of the exposure single-layer variants showed higher substance concentrations in the run-off water which decreased in the course of the exposition period. For the multilayer structures often lower concentrations at the start of exposure were observed. In the course of the exposition they rose and then fell again delayed below the concentrations of the single-layer variants.