Geopolymer matrix for fibre reinforced composites aimed at strengthening masonry structures

The paper presents the assessment of a metakaolin-slag-sodium-silicate GeoPolymer (GP) grout as a matrix for bonding four bidirectional meshes made of basalt, glass, carbon fibres and two unidirectional ultra-high tensile strength steel fabrics to soft mud and strong extruded clay bricks for strengthening purposes. A detailed chemical/physical characterization of the geopolymer is given, evidencing the completion of the geopolymerization reaction and the good stability of the geopolymer to leaching, freeze-thaw cycles and high temperature treatments as well as its adequate mechanical properties. Pull-off tests proved the excellent adhesion strength of the geopolymer grout, also embedding meshes and fabric, to both types of clay bricks.