Investigation on Building Materials with the SEM in the ESEM Mode to Demonstrate Their Capillarity Using the Contact Angle Method

Abstract

The chapter describes the use of the Scanning Electron Microscope (SEM) in the Environmental Scanning Electron Microscope (ESEM) mode on building materials, whose capillarity is to be examined. The abbreviation SEM means Scanning Electron Microscope. The abbreviation ESEM means Environmental Scanning Electron Microscope. On the basis of condensation in the ESEM, the hydrophobicity of capillary building materials is demonstrated with the help of the contact angle method. In the chapter, the investigation in the ESEM is shown using capillary building materials that have been given subsequent injections. Due to the problem of rising masonry moisture on capillary masonry in the absence of a cross-section sealing, injection agents, which have a hydrophobic and pore-filling effect, subsequently are used in the borehole method. Such a subsequent masonry sealing must be checked for effectiveness. In addition to already existing macroscopic methods, a new microscopic detection method is presented. This detection method uses ESEM technology in the SEM to generate and detect in situ dew processes at samples taken from the injection level of the examined masonry. The output of the results is done by image or film. By means of the condensation with the medium of water, the contact angle measurement method on the dew drops can be used to make accurate statements about the water-repellent capabilities of the examined sample and thus about the sealing success. There are detectable correlations to the macroscopic detection methods. The contact angles measured in the ESEM during condensation are connected to the conventional macroscopic measurement methods. The method presented in this chapter offers the advantage to have very small samples and to be investigated in a short time with very precise results. The new detection method is suitable for practical use.