Abstract: An extrudable cement-based material is formed from a mixture that includes cement in the range of about 40 to 90% by wet weight percent, a lightweight expanded aggregate in the range of about 10 to 60% by wet weight percent, a secondary material in the range of about 0.1 to 50% by wet weight percent, a reinforcement fiber in the range of about 1 to 20% by wet weight percent, a rheology modifying agent in the range of about 0.5 to 10% by wet weight percent, a retarder in the range of about 0.1 to 8% by wet weight percent, and water in the range of 10 to 60% of a total wet material weight.

Abstract: Hydraulically settable mixtures and methods for extruding such mixtures into a variety of objects which are form-stable in the green state are disclosed. High green strength is achieved by increasing the yield stress of the mixture while maintaining adequate extrudability. Optimizing the particle packing density while including a deficiency of water yields a hydraulically settable mixture which will flow under pressures typically associated with the extrusion of clay or plastic. In addition, a rheology-modifying agent can be added to increase the yield stress of the mixture while not significantly increasing the viscosity. The desired strength properties and other performance criteria of the final hardened extruded product are controlled by adding aggregates, fibers, a hydraulically settable binder, water, and other admixtures.