Full plaster test concept and device for building physic parameters
Creators: name: Hecht, Clemens
name: Reinthaler, Petra
name: Hecht, Clemens
Publisher: name: 8th Symposium on Building Physics in the Nordic Countries
Year: 2008

description: Despite the successful test and identification “refurbishment plaster” according to WTA in many cases salt efflorescence and damages on plaster systems appear. The main weakness of the standardised test is that the test conditions do not correspond to the real boundary conditions. The hardening of the plaster specimen occurs under optimal laboratorial conditions to achieve the best performance of the plaster system. That means the specimen can react properly without destructive agents. In practice the fresh mortar is affixed on masonry which has particular moisture and contingent salt load. So the setting process of the plaster runs under charged circumstances and may change expected properties of the hardened plaster. The special and important properties for salt resistance are only developed after setting. 

These effects of changed properties, triggered by moisture and salt load, are hard to estimate and forecast, the consequences are structural damages and dissatisfying appearance.

Scientific and technological objectives

The major interest and result of the new measurement method will be the declaration if the plaster system works or malfunctions. Furthermore the measurement system delivers material properties and characteristics under specific conditions which is a benefit for scientific and processing plaster. Climatic conditions as well as mistakes on handling can be arranged and created. So plaster and plaster systems can be measured under different influences and evaluated respectively adjusted in its composition and application. 

The technological objectives consist in the practicable use of the device, so climatic conditions, like temperature and air humidity can be varied and easily changed. The water and salt load will be inserted and realized trough an aerosol instead of contact directly to the salt solution or to a substrate. The load of aerosol is the basic concept, so no influencing substrate is needed. This opens the possibility to measure fresh plaster mortars and following their hardening under salt loading.

The device is a simple and robust construction which will be easy to apply and deliver fast results. There is no need for laboratory equipment, additional apparatus and experts. The measurement is possible under steady and unsteady conditions. The application potential ranges from testing and assessing materials to estimation of adverse conditions and consequences. 

Innovative character in relation to the state-of-the-art

Contrary to the state of the art the device and concept configures the test procedure more realistic. The advantages are:
• Existence of a simple, robust and easy to hand able device
• Possibility to test plaster in fresh as well as in hardened state. Therefore it is applicable over all life phases of the plaster. Additional information about setting up, setting conduct, serviceability and drying conduct under salt and moisture load can be determined if wanted.
• Adjustment of real existent on-site conditions due to kind and concentration of salt as well as climate conditions.
• The measurement concept is expandable to other (building) materials where salt and moisture loading/transport plays an important role.
• Determination of the influence of kind and concentration of salts (comparison moisture with and without salt loading) on the plaster structure and serviceability.