## 1 Introduction
This physical interface's properties are affected by many factors, such as the capability of the adhesive mortar to penetrate into the concrete and into the concrete micro-cracks, the borehole roughness [8; 9], the possible chemical interaction between the adhesive mortar and concrete, and the possible presence of residual dust in the borehole. The so-called inner interface is not a physical one; it is, rather, a crack propagation path dictated by the threaded bar geometry. Since the inner interface failure happens through the adhesive mortar material, it could be considered an adhesive mortar Mode II problem only. Figure 1: Testing setup configurations: unconfined test setup (**a**) and confined test setup (**b**), and (**c**) test setup recommended by RILEM standards used to determine the bond properties of reinforced concrete elements. Figure 2b shows a possible failure mechanism of adhesive anchors tested in a confined configuration, where failure involved both the inner and the outer interfaces. In an unconfined configuration, several failure mechanisms under tensile loading can be obtained [6]. Figure 3a and Figure 3b show the steel failure and the concrete splitting failure, respectively (failure mechanisms also shared by mechanical anchors [10]). If the embedment depth is short, concrete cone failure (or concrete breakout) can be expected (see Figure 3c). The mixed-mode failure begins as a concrete cone failure and continues through the anchor's outer (see Figure 3d) or inner (see Figure 3e) interface (see [4]). In the former case, the failure can either keep progressing along the outer physical interface until the end of the anchor, or it can cross the adhesive mortar layer and continue along the inner interface until the end of the anchor (see Figure 3f). In this contribution, a new test setup that can be used to obtain the adhesive anchor bond properties in a confined configuration is presented. The test setup aims at improving the reproducibility of the bond strength determination, especially for mortars with a very high bond strength. These mortars have to be qualified in a confined configuration to avoid concrete cone failure, with a short embedment depth to avoid steel failure. In this case, the concrete contribution to the anchor failure mechanism and failure load may become non-negligible due to the support used for the confined test and the concrete surface influence. The test setup also aims at improving the stability of the test, allowing for a consistent post-peak characterisation by controlling the test with the unloaded-end anchor displace  
Figure 3: Failure mechanisms of adhesive anchors under tensile loading: (**a**) steel failure, (**b**) concrete splitting failure, (**c**) concrete cone failure. Bond/Concrete mixed failure mode involving (**d**) outer interface failure, (**e**) inner interface failure, and (**f**) both outer and inner interface failure. Figure 2: Outer and inner interface positions shown in an adhesive anchor longitudinal section (**a**), and example of confined test failure involving both the outer and the inner interfaces (**b**). ment as done for cast-in rebars. This point is important to facilitate the stress-slip law determination with the proposed numerical method. The proposed setup is an adaptation of the one proposed from RILEM technical recommendations [11] that is used to identify the bond properties of reinforcing steel elements embedded in concrete. The method used for reinforcing steel elements embedded in concrete (cast-in rebars) is suitable for the identification of the bond properties of a system with a unique interface (steel-concrete). Post-installed anchors present two interfaces, and the installation process requires modifications in order to expose the unloaded end of the anchor. In addition, a novel method used for the stress-slip law inverse identification is proposed and applied on a sub-set of the experimental results.