## 3 Results  
### Measurements at Modular Specim  
Figures 9 and 10 show the measurement results of all three scenarios at one respective floor construction. The first covers the configuration of a 7 cm CT screed combined with a 10 cm EPS insulation. The B-scans on top also contain text information about the underlying moisture states of screed and insulation, as well as the performed neutron probe measurement. All exemplary radar results were collected along survey line 1 (see Figure 6). According to the general assumption mentioned in Section 2.5.2, the dry measurement in (a) has a homogeneous reflection pattern, whereas the two damage scenarios in (b) and (c) present clear deviations at specific time-spans. For the insulation damage in (b), we see amplitude changes in the second (RW2) and third (RW3) reflection around 2.5 ns to 3 ns, which come from the affected layer. Water added to EPS usually gathers inside the insulation joints, and from there, it slowly penetrates the material. Therefore, the areas of higher attenuation were located horizontally around the survey line's center, where the joint is crossed. These deviations become even clearer by considering the respective A-scan feature vector plots below each B-scan. Compared to the relatively flat lines for the dry measurement in (d), \(F_{2}\) (\(A_{RW2}\)) particularly shows significant variations in (e), which is also captured by an increased standard deviation (\(F_{B}\)). These deviations are not immediately recognizable in the B-scan, since the third reflection RW3 shows a more significant variance. Insulation of 10 cm thickness usually developed two reflections, whereby the latter and therefore third reflection was not covered by the used feature set. However, due to their interference, RW2 also experienced a change in amplitude and is therefore suitable for recognizing damage. Since the neutron probe is more sensitive to moisture closer to its radiation source, a small amount of water inside the insulation is not sufficient to cause a significant increase. In the case of screed damage in (c), the water induces deviations which appear in earlier time-spans, like in the direct wave DW or the first reflection RW1. As shown in Figure 5, all screed samples were poured from above, which is why the DW experiences a significant drop in its amplitude compared to other scenarios. \(A_{DW}\) is especially sensitive to superficial material properties and is therefore an appropriate feature to recognize flooding damage. In this case, \(F_{4}\) being the ratio of \(A_{RW1}\) and \(A_{DW}\) shows a high dynamic in (f). Figure 9: Measurements at a 7 cm CT and 10 cm EPS floor construction for the scenarios: (**a**) Dry, (**b**) damage insulation, and (**c**) damage screed. The bottom (**d–f**) shows the respective A-scan vector plots for each B-scan (top). This is also because an unexpected reflection occurs at around 1.4 ns right after the direct wave, which was not present in other scenarios. The reason could be a steep water gradient providing a strong permittivity contrast and therefore a new reflector. This assumption is supported by the highest NMR amplitude measured for the 7 cm CT among all screeds, which was around 90 at the sample's surface. The other screeds had values of around 60 and did not show an extra reflection (compare Figure 10). Here, the new reflection at around 1.4 ns is interpreted as RW1, whereby the former RW1, originating from the screed bottom, is then seen as RW2. After a decrease of \(A_{\text{RWI}}\) between A-scans 50 and 65, it completely disappears between 70 and 80, causing a shift in reflection-counting. This leads to dominant jumps for \(F_{2}\) and \(F_{4}\), which cause an increased standard deviation and support the feature's sensitivity for water-induced deviations. The neutron probe is also capable of recognizing the increased moisture content with a difference of 4 digits compared to the dry measurement. Figure 10 gives another example of a 5 cm CA screed and 6 cm GW floor construction.