Integrated micro and nano-silica in advanced composite high-strength mortar for TRM system

Abstract

This study presents the development of a high-strength composite mortar for Textile Reinforced Mortar (TRM) systems through the synergistic integration of micro-silica, nano-silica, silica sand, and hybrid fibers. The combination of steel and basalt fibers significantly enhanced the mechanical and bonding performance of the mortar. The optimized mix achieved compressive, split tensile, and flexural strengths of 70.335 MPa, 8.03 MPa, and 19.63 MPa, respectively, while demonstrating improved bonding behavior with an 80.5% increase in splitting bond strength, direct pull-off bond strength of 8.5 MPa, and pull-out bond strength of 7.0 MPa. These improvements are attributed to the densified microstructure and refined interfacial transition zone resulting from the pozzolanic reactions of micro- and nano-silica. The findings confirm that the combined use of multi-scale silica materials and hybrid fibers produces superior mechanical strength, durability, and adhesion, making the developed mortar a promising solution for retrofitting and strengthening applications in modern construction.