Investigations into the cracking behaviour of epoxy-impregnated textile-reinforced concrete

Abstract

Textile-reinforced concrete is a novel composite material consisting of high-performance textile fabrics and high-strength concrete. Due to differences in the shape and the mechanical properties of the reinforcement, a direct transfer of existing knowledge on the bond behaviour of steel reinforcement is not possible. While it has been shown in the past that the geometric properties of the textile reinforcement are essential parameters that influence the bond properties, few investigations have been carried out on the cracking behaviour of textile-reinforced concrete itself. In this paper, the results of an extensive experimental campaign on the crack progression in textile-reinforced concrete elements under uniaxial tension is presented. In total 48 test specimens with different geometric properties and different surface characteristics were monitored during testing with advanced measuring techniques such as digital image correlation (DIC). This allows for an evaluation of the crack widths at different load stages. Additionally, laser scans on all tested fibre strands were conducted in order to get 3d-models of the different fabrics used. The geometry determined from these scans is linked to the results from the uniaxial tensile tests. The results clearly indicate the dependence of the cracking behaviour on the shape of the different textile types. Furthermore, if the crack width is a decisive criterion in the serviceability limit state, an additional sand coating guarantees smaller crack widths and distances.