Mechanical properties of FRCM using carbon fabrics with different coating treatments

Abstract

The use of composite materials for repair and retrofit of structures has become a common use among the engineering community. Fabric Reinforced Cementitious Matrix (FRCM) is a composite material specifically designed for masonry and concrete rehabilitation and is becoming a viable alternative to FRP, whenever the project conditions do not allow the use of organic polymer based composites. FRCM is usually constituted by one or multiple plies of dry fabrics (carbon, glass, aramid, basalt or PBO fibers) embedded into an inorganic matrix. If a polymer is used to either cover or bond the fabric strands, such polymer does not fully penetrate and impregnate the fibers as it would for FRP. The purpose of this research work is to study how different types and amounts of organic coatings applied to a carbon fabric could affect the bond behavior between fabric and mortar. The effectiveness of coating treatments was studied by means of direct tensile, pull-off and shear-bond double-lap tests. Experimentation was carried out on different combinations of fabrics and mortars, by varying the levels of pre-impregnation of the fabric during its manufacturing. In addition, the use of a quartz sand layer applied to the fabric after impregnation was investigated. Experimental evidence shows a promising enhancement of the bond between fabric and matrix and, therefore, of the entire system even with the use of low percentages of resin, depending on the type of mortar used.