Rheology of fiber-reinforced concrete (FRC)

Abstract

3D concrete printing(3DCP) has been gaining traction in the civil industry due to the benefits it offers. However, due to the brittleness of concrete, steel reinforcement is needed but the incorporation of reinforcement is difficult to incorporate into 3DCP. As such, the number of printable concrete is limited. A good understanding of the rheology of concrete is required to determine if a material is printable. This FYP study investigated the effect of incorporating fibers to the concrete prior to the conduct of the rheological test. Normally, when researchers carry out rheological tests, they do so using mortars. Fibers will only be added after the rheological tests and before carrying out other tests such as compression tests and tensile tests. In this study, PVA fibers were used and their volumetric content added ranged from 0 to 2%. Before carrying out the experiments with different PVA fiber volume content, experiments were first carried out to determine the concentration of VMA to be added. SP and VMA had to be included as the FRC mixture turned out to be too stiff without the admixtures and it was impossible for the rotating bar of the rheometer to rotate in the mixture. The results obtained from the rheological tests showed that it was possible to conduct rheological tests on FRC up to but not including 1.5% PVA fibers. Besides investigating if it was possible to conduct the tests, rheological properties for the FRC samples with different VMA and PVA fiber content were obtained as well. The FRC samples were also further tested in order to obtain their compression strength and tensile properties.