Dry mineral pre-impregnation for enhancing the properties of glass FRCM composites

Abstract

The objective of this study was to improve interface bonding in composite materials consisting of glass textiles embedded in a mineral matrix, commonly termed Fabric Reinforced Cementitious Matrix (FRCM). The use of these materials is considered a suitable solution for repairing and strengthening existing masonry or concrete. Two pre-impregnation methods were used: the wet and dry methods. The wet method consists in immersing a textile in a slurry of fillers and water. This process has already been applied in the literature and improved the mechanical properties of the composite. However, it is difficult, long and can be used only for prefabrication. The dry method is a new solution based on the application of an alternating electrostatic field that causes powder to penetrate into textile bundles. Its main advantage is the possibility of strengthening and repairing structures in situ. Five kinds of unidirectional glass textiles were used, embedded in an ettringitic matrix. Three configurations were tested: a non pre-impregated textile (REF), a textile pre-impregnated according to the wet method (PIW), and a textile pre-impregnated with the dry method (PID). The results of tensile tests and Digital Image Correlation (DIC) analysis are shown and discussed. It was found that the mechanical properties of the composite could be improved by pre-impregnating textiles. The magnitude and efficiency of this improvement was highly dependent on the pre-impregnation process, textile area density and the assembly method of the filaments constituting the textile yarns. The best performance was obtained with the dry pre-impregnation process.