## 6 Conclusions and Future Developments  
The extensive experimental campaign presented in this work allowed better understanding the involved phenomena and the effect of individual components (matrix, textile and short fibres) on the tensile behaviour of TRC composites. In this sense, the use of the efficiency and the ductility/energy absorption parameters introduced in this work represent a systematic approach for the comparison of alternative TRC configurations and for the assessment of synergic contributions. From the interpretation of the experimental results, it can be concluded that:  
* The coating nature and the fabric weaving had a significant influence on the global capacity of the composites, mainly in terms of global efficiency; both the reduction of the filaments that effectively participated in the mechanical response and the variation in the bond-slip behaviour at the fabric/matrix interface played a significant role. * In general, the addition of short fibres was reflected in an increase of the mechanical capacities and a better behaviour in terms of durability. This effect seemed to be less visible in the case of narrow-spaced textiles, or when the matrix choice entailed a reduced fibre pull-out strength. * The differences between matrices designed for different applications (new constructions vs. retrofitting) should be considered not only in terms of first cracking strength and initial elastic stiffness, but also in view of better understanding the global response of TRC composites. In particular, the internal slippage of the fabric--favoured by the use of less compact matrices--may significantly reduce the stiffness of the third branch of the curve, affecting the ultimate capacity of the composite. * To obtain efficient tensile responses also when heavy-duty textiles are adopted, it might be necessary to slightly increase the thickness of the specimens, better controlling the internal slippage between the fabric and the surrounding matrix. Cost-effective solutions were obtained by carefully combining the different components, in view of minimising the waste of material while improving the overall mechanical capacity. In this sense, the aims of the optimisation process were the maximisation of the efficiency (both the \(EF_{TRC}\) and the \(EF_{TRC,f}\)) and of the energy absorption capacity. The application of the stochastic cracking model showed that it was possible to simulate the experimental tensile curves with a good correlation, starting from assumptions directly derived from standard tests results (Section 5.3). The fabric efficiency factor \(EF_{f}\) appeared to be directly related to the slope of the third branch in the stress-strain composite behaviour on condition that the transverse deformation of the fabric was limited. In the attempt to provide a predictive capacity to the model,  
Figure 23: Effect of fabric efficiency on the predicted analytical response and comparison with the experimental data in terms of nominal stress vs. strain for M1-based (**a**) and M2-based (**b**) composites reinforced with F7 fabric. it might be necessary: (i) to implement the effect of added fibres, so as to capture the second stage stress increase and the correct extent of the multi-cracking zone (this last directly correlated to the variation of the cracking pattern development due to fibres addition); (ii) to investigate the non-linear nature of the bond-slip behaviour between the fabric and the matrix by means of pull-out tests, even if this might overcomplicate the model; (iii) to better evaluate the cracking tensile stress of the employed matrix, for instance by means of direct tensile tests on more representative specimens (e.g., with the same nominal dimensions and the same mortar compaction of the TRC composites); and (iv) to develop a method to assess the fabric elastic behaviour, when transversely restrained by the mortar (furtherly investigating the effects of crimp, yarns diameter and grid spacing on the fabric \"Poisson\" effect). Conceptualisation, M.C.R., G.Z., M.C. and M.d.P.