## 4 Results and Discussion
### Experimental Results of CTRC  
To evaluate the load-bearing behavior of CTRC, initially, the tensile strength F\({}_{\text{T}}\) and reduction factor K\({}_{\text{T}}\) of the CTRC uniaxial tensile specimens was analyzed. For CTRC-EP-Sand, no influence of tempering was observed on the tensile strength with increasing test temperature. The tensile strength decreased up to 2% at 40 \({}^{\circ}\)C and 5% at 70 \({}^{\circ}\)C compared to room temperature, cf. Figure 11. However, for CTRC-P, tempering with AH led to a 23% decrease in tensile strength. As hypothesized in Section 4.1.1, this might be attributed to the softening of the impregnation. The comparison of the experimental findings with the literature reveals that the reduction factors correspond to the AH test results reported by [1; 20]. Conversely, the results from [19] exhibit substantial deviations. The investigated material combinations indicated a decrease in tensile strength with increasing testing temperature and no adverse effects on the tensile strength of CTRC due to the electrical heating process. Additionally, the influence of the SRM-A4 layer on the CTR can be examined in the comparison between the tensile strength results of the CTR, cf. Figure 8 (Section 4.1.1), and CTRC, cf. Figure 12. A partly higher tensile strength is achieved in the CTR tests than in the CTRC uniaxial tensile specimens. This elevated strength is observed for both the EH and AH processes. The ratio of CTRC's tensile strength to that of CTR, based on the averages, is at a minimum of 96% at 20 \({}^{\circ}\)C for CTRC-EP-Sand. In comparison, the ratio for CTRC-P is lower, with a minimum value of 86% at 20 \({}^{\circ}\)C. The authors assume that the increased textile strength can be attributed to mechanical bonding effects. Additional coating with sand enhances the bond to the mortar. In the tensile testing of CTRC-EP-Sand, the mechanical behavior of the fiber strand is not affected, whereas in CTRC-P, the additional coating is absent and local mechanical effects can occur. Furthermore, as explained by [1; 40], higher textile strength can be ascribed to the distribution of force applied through transverse  
Figure 10: Mean values of the tensile strength with standard deviation of SRM-A4 at increasing testing temperatures. pressure on multiple fiber strands of the CTR, unlike single roving, resulting in more uniform load distribution. Additionally, the method of testing can also impact the results. Firstly, the fiber strand tensile test is conducted without transverse pressure. Secondly, an imprecise alignment of CTRC in the clamping mechanism may induce multi-axial loads and consequently lead to decreased tensile strength. When comparing the strain at failure, there was no variation for CTRC-EP-Sand heated with AH, cf. Figure 13. However, the results from the EH test series indicated a decrease in strain with increasing test temperature by 12% compared to 20 \({}^{\circ}\)C. For CTRC-P, the strain did not exhibit a clear trend with increasing test temperature and demonstrated a high standard deviation. Regarding the investigation of the influence of EH, the results were not consistent for the two examined materials. Consequently, a uniform conclusion cannot be reached; nevertheless, it is noteworthy that the effect of EH on strain is not typical. Figure 11: Mean values of the tensile strength of CTRC uniaxial tensile specimen for EH and AH with standard deviation. Figure 12: Reduction factor K\({}_{\text{T}}\) shown as mean values of tensile strength with standard deviation for CTRC [1,19,20,22,23]. With the assistance of DIC measurements and the evaluation tool ACE, crack width and crack distribution were analyzed. Figure 14 demonstrates the relationship between tensile strength and crack width opening in correlation to strain for an exemplary CTRC specimen. The lines in blue depict the width of an individual crack within the specimen. Three distinct stages can be identified: the uncracked stage, crack development and the final crack pattern.