Out-of-plane performance of structurally and energy retrofitted masonry walls: geopolymer versus cement-based textile-reinforced mortar combined with thermal insulation

Abstract

This paper examines the out-of-plane performance of masonry walls (representative of infills in reinforced concrete frames) which have been upgraded with an outer skin of integrated structural and an energy retrofitting system. The benefits of such an integrated system are mainly cost-related. Nevertheless, before moving to full-scale applications, additional benefits to the structural performance need to be investigated. In this study, the examined configurations of this composite system comprised either thermal insulation boards bonded directly to the wall followed by layers of textile-reinforced mortar (TRM), or thermal insulation boards bonded in-between two TRM layers. Other than the retrofitting layers configuration, the following parameters were also investigated: a) the binder type (cement-based versus geopolymer-based mortars), and b) the textile type (open mesh glass fibre textile versus basalt fibre textile). The results of this experimental study are discussed in terms of failure modes, post-cracking stiffness and ultimate capacities. Overall, this study highlights the mechanical benefits of the TRM plus thermal insulation system while providing insights on the bond performance between the different materials selected. An important finding is that the integrated system is even more effective than a standard TRM application. Finally, the geopolymer mortar seems to be equivalent in terms of performance to the commercially available cement-based mortars.

Bond of textile-reinforced belite calcium sulfoaluminate cement mortar to concrete substrate

“…However, the lack of research on the effect of the matrices of TRM systems might carry the notion that the type of textile and the substrate have the main influence on the strengthening performance. In contrast, the recent findings of the authors showed that the mortar type can also have a significant influence on the effectiveness of the TRM application [27][28][29].…”

The Challenge of Integrating Seismic and Energy Retrofitting of Buildings: An Opportunity for Sustainable Materials?

“…polymers mortar matrixes have not reached adequately high levels of performance to allow for the complete substitution of thermal insulators. Recent studies investigated the performance of an integrated solution employing geopolymer-based TRM together with a thermal insulation system, showing advantages also in terms of structural response (e.g., out-of-plane capacity) thanks to the increased lever arm of the TRM layer position with respect to the substrate [67]. Systematic investigations to assess the thermal performance of TRM systems incorporating insulators remain limited.…”