Hydraulically settable mixtures and methods for extruding such mixtures into a variety of objects which are form-stable in the green state. 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.