## 2 Materials and Methods
### Test Procedures  
The ambient temperature tests were performed following the standard unconfined tension test setup for technical approvals, specified in TR 048 [30]. The loading setup consisted of a displacement-controlled system, which allowed capturing the post-peak behavior of the anchor. A hydraulic jack transferred the load to the anchor through a high-strength steel rod, which was connected to a hollow cylinder cage, itself connected to the free end of the anchor by two coupling nuts. To prevent the vertical movement of the slab, the jack was supported by a steel ring, which rested directly on the slab. The dimension of the support was chosen sufficiently large, i.e., the diameter was larger than 4\(\times\)h\({}_{\text{ef}}\) to allow the formation of an unrestricted cone. The applied load was measured by a load cell placed on the top of the load cylinder. For measuring the anchor displacement, a linear variable differential transformer (LVDT) was installed on the top of the anchor in such a way that its axis and that of the anchor coincided.  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & Exterior diameter & 16 mm \\
**Threaded rod** & Threads & 2 mm \\  & Steel strength class & 12.9 \\ \hline
**Adhesive mortar** & Mean bond resistance & 27 MPa \\ \hline  & Aggregate size & 4 mm–10 mm \\  & Cement quantity & 286 kg/m\({}^{3}\) \\  & Water/cement ratio & 0.54 \\
**Concrete** & Cube compressive strength f\({}_{\text{cc}}\) & 33.6 MPa \\  & Tensile strength f\({}_{\text{t}}\) & 2.8 MPa \\  & Fracture energy G\({}_{\text{F}}\) & 71 J/m\({}^{2}\) \\  & Young’s modulus E & 26.9 GPa \\ \hline  & & \\ \end{tabular}
\begin{tabular}{c} 1. Cast-in place rod with thermocouples scale for measuring temperatures of concrete \\
2. Post-installed anchor \\ (loaded) \\
3. Post-installed anchor with thermocouples scale for measuring temperatures of \\ mortar (non-loaded) \\ \end{tabular}
\end{table}
Table 2: Characteristics of the materials.  
Figure 1: Positions of the thermocouples.  
For the slow-rate heating tests, the procedure consisted of two steps: the entire surface of the slab including the anchor was first heated with an electric heater, then after 3 h 30 min of exposure, the heater was removed, and a standard unconfined tension test was performed. Five to ten minutes were needed after the end of the heating to install the tension test setup, then the failure occurred 1 min to 3 min after the beginning of the test. Figure 2 shows the typical test setup for the tension tests at ambient temperature and for tests at high temperature after removing the electric heater.  
For the tests with ISO 834-1 fire conditions, the thermal loading was ensured by a gas furnace, which heated the test specimen placed above the fire (Figure 3). Therefore, the slab was positioned upside down. The furnace was surmounted by a metallic frame, to which the mechanical loading equipment was directly fixed. The displacement imposed by the jack was transferred to the anchor via a rigid steel frame.  
Figure 3: Setup for standard ISO 834-1 fire tests.  
Figure 2: Test setup for tension tests at ambient temperature and after slow-rate heating.  
The first phase of the test consisted of heating the slab without applying a mechanical load. However, the self-weight of the rigid steel frame stressed the anchor permanently with a constant load of about 0.7 kN. The tests were performed exactly after 37 min (T125 ISO-30), 60 min (T125 ISO-60) and 75 min of exposure (T125 ISO-75) without stopping the heating. The failure occurred 3 min to 5 min after the beginning of the test, respectively, 40 min, 65 min and 78 min after the beginning of the heating.