Hierarchical composite coating for enhancing the tensile behaviour of textile-reinforced mortar (TRM)

We describe a novel class of interface-functionalised textile-reinforced mortar (TRM) composite materials reinforced with basalt and alkali-resistant glass multifilament textiles embedded in a commercially available hybrid lime-cement mortar, usually applied for masonry retrofitting. Spotlight is set on improving the mechanical (tensile) performance of the system through a scalable and easy-to-apply surface treatment for the dry textiles. The treatment consists in soaking the textiles in highly-diluted epoxy resin, to which rice husk ash (RHA) is later added, acting as pozzolanic filler. The resulting functionalised textiles exhibit remarkable adhesion with the matrix owing to the presence of RHA having high specific surface area and rich amorphous content. Three different RHA powders are assessed and their performance is compared to that of plain silica fume. The role of RHA milling is also discussed. The RHA/epoxy coating significantly improves the ultimate tensile strength and energy dissipation capability of the TRMs. In particular, for basalt-textile reinforced composites, the mean tensile strength is three times as large as that of uncoated specimens, whereas the dissipated energy at failure is nearly four times as much. Furthermore, the surface treatment qualitatively changes the cracking pattern of the TRMs, for many diffused small cracks appear during tensile testing, and this provides evidence of effective stress distribution in the matrix as a result of superior interface adhesion. •A novel surface coating for textile-reinforced mortar composite system is proposed.•The coating is epoxy-based and uses rice husk ash (RHA) particles as active filler.•Three RHA powders are considered differing by rice variety and combustion process.•Uniaxial tensile tests on basalt- and glass-TRM prismatic coupons are conducted.•The coating leads to enhanced strength, toughness and crack pattern in TRM samples.