PSI - Issue 78

Francesco Ascione et al. / Procedia Structural Integrity 78 (2026) 1334–1341

1335

Keywords: Alkali-activated materials; CO2 emissions reduction; Masonry reinforcement; Sustainable construction; Textile reinforced systems

1. Introduction In recent times, textile-reinforced (TR) composites emerged as promising materials in civil engineering, due to their good mechanical properties and adaptability to various applications (Caso et al. (2012); Nanni (2012)). These systems consist of high-performance textiles embedded within an inorganic matrix, offering advantages such as a high strength-to-weight ratio, straightforward installation, and minimal disruption during implementation (Bencardino & Condello (2016) ; D’Antino & Papanicolaou (2017)). Nonetheless, despite their structural merits, environmental concerns regarding TR composites persist. Traditional matrices based on ordinary Portland cement (OPC), though mechanically reliable, are associated with substantial carbon emissions and high energy demand during production. Additionally, synthetic textiles commonly used in these systems pose sustainability challenges, primarily due to their persistence in the environment and their role in microplastic contamination. A viable strategy involves the integration of mineral-based or low-impact synthetic fibres — such as basalt — with alternative binder systems characterised by minimal or zero cement content. Among these, alkali-activated materials (AAMs) gained considerable attention as a sustainable substitute for OPC (Provis (2018)). AAMs are formed through the chemical activation of aluminosilicate rich precursors — often industrial residues like ground granulated blast furnace slag (GGBFS) or fly ash — using alkaline agents (Provis, (2018)). The mechanical behaviour of “green” TR systems, incorporating alkali -activated matrices and a variety of textiles, is the subject of a limited but growing body of research. These systems demonstrated promising tensile and bond performance, along with improved environmental characteristics compared to traditional cement- or lime-based TR counterparts as reported by (Candamano et al. (2020); Constâncio Trindade et al. (2017); Donnini et al. (2024); Longo et al. (2020); Tamburini et al. (2017)). From a structural perspective, several experimental studies confirmed the potential of “green” TR systems in improving the mechanical performance of masonry walls subjected to diagonal compression, in-plane and out-of-plane bending, and shear. Cholostiakow et al. (2023) tested single-leaf clay brick walls, strengthened using either cement-based TR or “green” TR systems with metakaolin – potassium silicate matrices and basalt or glass fibre textiles. “Green” TR systems, particularly with two-sided application, significantly enhanced ductility and showed comparable or improved strength relative to cement-based TR systems. Libre et al. (2023) used bamboo-fibre textiles embedded in an alkali-activated matrix composed of fly ash and mill scale, reinforced with chopped bamboo fibres, to strengthen similar wallettes. Two-sided green TR systems application resulted in a 50% increase in ductility ratio compared to control specimens. Gkournelos et al. (2022) investigated double-leaf natural stone walls bonded with cement/lime mortar and strengthened with either a traditional lime-based TR systems using flax fibres or a “green” TR system based on metakaolin/slag matrix with coated basalt fibres. Under cyclic in-plane, out-of-plane, and shear loading, “green” TR systems improved both strength and stiffness, though premature failure due to fibre degradation in the alkaline matrix was noted. Although these advantages, the considerable number of parameters affecting the performance of alkali-activated mortars hindered the development of standardised and optimised mix designs that effectively balance mechanical strength, durability, and environmental sustainability. The absence of a unified framework for these materials highlights the complexity of the system and the need for further in-depth research. In response to this challenge, the present study aims to advance the current understanding of environmentally sustainable TR composites by evaluating the mechanical performance of systems incorporating alkali-activated matrices and reinforced with basalt and steel textiles. In this work, a preliminary experimental investigation was carried out, encompassing tensile testing of the textile reinforcements and TR systems as well as the mechanical evaluation of the alkali-activated mortars. Furthermore, the study extended to the structural assessment of clay brick masonry columns confined with TR systems, thereby addressing both material- and component-scale behaviour. The findings were benchmarked against those of conventional, commercially available TR solutions, enabling a critical comparison of the structural efficiency and ecological benefits offered by the proposed formulations. This research provides new insights into the feasibility of combining low-impact matrices with mineral and metallic textiles for structural strengthening applications. The outcomes not only contribute to the body of knowledge on alkali-activated composites but also represent a step forward in the development of high-performance, sustainable reinforcement systems — offering a novel and practical alternative to traditional cement- and synthetic fibre-based solutions.