PROCESSING TECHNIQUE TO IMPREGNATE GLASS FIBRE MATS FOR TEXTILE REINFORCED CEMENTITIOUS COMPOSITES

Future applications of glassfibre textile reinforced cementitious composites (GTRC), such as for example building elements, require a high fibre volume fraction in able to resist to considerable high tensile forces. Common production processes for cement composites like spray-up seem unable to satisfy this requirement, and thus keep the use of GTRC for building applications limited to non load bearing elements. Hand lay-up, with its known disadvantages of low volume production, seems at the moment the only valid processing technique for obtaining a high fibre content.
The Vrije Universiteit Brussel developed a self compacting impregnator (SCI) to pre-process the impregnation of a glass fibre structure by the cement matrix in an industrially attractive way.,Two or more continuous textiles are feeded between two horizontal rotating cylinders, and are impregnated by the cement matrix which is continuously fed and residing in a bath between the cylinders. The resulting wet prepreg contains a fibre volume fraction which can reach 25%, 3 to 10 times higher than the conventionally used spray-up technique for cement composites.
This paper will explain the basic principles of this mechanical impregnator, and quantify the impregnation quality compared to the hand lay-up processing technique. For comparison, uniaxial and biaxial tensile tests are performed on laminates produced with both processing techniques. The biaxial experiments are performed on cruciform shaped samples in a purposely built setup with four individual hydraulic actuators, to avoid second order effects. All tests are monitored with strain gages, Digital Image Correlation and ESPI measuring techniques.