## 5 Conclusions  
The main drive for use of lightweight matrices in TRMs is to provide heat shielding to the reinforcement (fibrous grid) since lightweight mortars are characterized by lower heat conductivity with respect to normal weight ones. Nevertheless, the design of lightweight aggregate (e.g., pumice) cement-based mortars suitable for TRMs (i.e., comparable to normal weight ones, in terms of--at least --strength) requires high strength pastes with low effective water-to-cementitious material ratios in order to compensate for the low crushing strength of the lightweight aggregates. The latter aggregates, which are often used in a fully saturated condition in the mixture, provide larger quantities of evaporable (and non-evaporable) moisture (in comparison to normal weight mortars) leading to: (i) early-age swelling (once wet curing is concluded), (ii) stress buildup during moisture evaporation by heating (dense paste causing high vapor pressure), and (iii) differential shrinkage cracking (along all TRM/masonry joints' interfaces). Hence, it is highlighted that a crucial parameter for the comparison of the post-heating residual shear bond response of different TRM systems on a reasonable basis is their moisture content. This must be kept at a constant (comparable) level, which is difficult to achieve and monitor. The main conclusions drawn from the experimental results presented in this work are summarized as follows. At control conditions (non-heated specimens) and after exposure at a nominal air temperature of 120 \({}^{\circ}\)C, both single-layer TRM systems (TRNM and TRLM) exhibit similar bond capacities. The same does not apply for the nominal exposure temperature of 200 \({}^{\circ}\)C for which single-layer and double-layer TRNM overlays outperform the respective TRLM ones in terms of residual bond capacity. For TRLM overlays, the maximum textile axial stress decreases by 50% and 36% for specimens subjected to 200 \({}^{\circ}\)C with single-layer and double- layer overlays, respectively, in comparison to the maximum textile axial stress of the reference specimens. Increase of mortar thickness (to accommodate higher fiber volume fractions, i.e., more textile layers) seems to be beneficial in terms of post-heating residual bond capacity. The relevant knowledge curve is at the beginning of its ascending branch. There are still many open questions to be answered (apart from the issue of moisture control). The object of the current study is a multi-parametric problem, which is hard to draw generalized conclusions from. There is a multitude of constituent material combinations comprising different TRM systems, which, in turn, can be combined with a vast array of different masonry substrates (all--adjacent materials--possessing different shrinkage strain potentials, porosity, and transport properties to mention a few). Per TRM/substrate combination, it would be interesting to assess the effects of hygro-thermal fatigue scenarios. Figure 8: Response curves of representative specimens reinforced with: (**a**) TRNM and (**b**) TRLM overlays. **Author Contributions**: [PERSON] is the author of the draft manuscript. Additionally, she participated in the planning of the experimental program and was responsible for the construction/curing/handling of the specimens, the execution of the experimental program, the data treatment, and the derivation of preliminary conclusions. [PERSON] was in charge for the planning of the experimental program. She performed a critical evaluation of the experimental results and edited the manuscript. Lastly, [PERSON] was responsible for the mix design of the mortars. He also offered his help in the mechanical characterization of the materials used. **Funding**: The research described in this paper has been co-financed by the European Union (European Social Fund--ESF) and Greek national funds through the Operational Program \"Human resource development, education, and lifelong learning\" of NSRF 2014-2020, Project \"Supporting researchers with emphasis on young researchers--EDVM34\".