Test Tube PLEYERS
Introduction
In both building materials technology and stone restoration, the examination of the absorption of fluids of porous materials is of great importance. In stone restoration, among other things, it provides insights into the material properties and the associated assessment of the weathering behaviour, which in turn is used for the later evaluation of conservation measures. In building materials technology, the investigation of liquid absorption is used, for example, to test the water tightness of exterior walls and concrete, or to assess the penetration behaviour of impregnating materials and their long-term efficiency. The determination of the water absorption coefficient plays a decisive role here. The following section discusses the so-called test tube according to Pleyers as a measuring method for the water absorption coefficient.
Test tube according to Pleyers
The test tube according to Pleyers (Fig. 1) is used to determine the liquid absorption of porous building materials. It was patented in 1999 by Dipl.-Ing. Gerd Pleyers and is based on the Karsten test tube. A disadvantage of the Karsten test tube is that it is not possible to determine the indenter parallel to the surface and thus reliably assess the depth of penetration. The two measuring tubes also vary in their design. The test tube according to Karsten is made of a glass body with a liquid chamber. This is followed by a tube with a measuring scale, with which the amount of liquid absorbed can be read off in ml. Pleyer's test tube, on the other hand, has two liquid chambers, one inside and one outside, both of which are connected to a respective riser tube. Only the riser tube connected to the inner chamber has a scale in l/m2. The inner chamber is used to test the surface of the building material, while the outer chamber enables the cylindrical spreading of the liquid in the inner chamber. It is important that the outer chamber is filled with liquid the entire time, otherwise the liquid in the inner chamber will not spread one-dimensionally into the test object, as in the Karsten test tube. This device enables an exact, directly readable determination of the water absorption coefficient.