Rheology of extruded cement-based materials

Current research efforts seek to develop extruded high-performance fiber-reinforced cement-based composites (HPFRCC) for use in residential housing applications. Part of this effort focuses on reducing the high material cost that is associated with extrusion processing by replacing costly cellulose ethers with less expensive clay binders. The minimum amount of two different types of cellulose ethers that was needed to achieve extrudability was determined and then the possibility of reducing the ethers,with two clay binders was explored. The results show that cellulose ether content can be reduced by using alternate clay binders. In addition, two different extrusion-based rheological characterization methods were used to describe the fresh state properties of the extruded materials: the Benbow-Bridgwater model and capillary rheology. Capillary rheology was shown to be effective at describing extrudability, providing an indication of the fresh state parameters necessary for extrusion.