| 摘要 |
<p>EXTRUSION CASTING APPARATUS Apparatus for manufacturing precast, prestressed, hollow-core, concrete slabs, including an extruder which is movable along a fixed casting bed to extrude from a relatively dry concrete mix a slab having longitudinally extending hollow cores and grout keyways extending along the slab sides. Multiple, core-forming augers in the extruder are shaped and positioned with respect to a feed opening in the extruder in a manner which eliminates cavitations in the slab and provides smooth, well formed slab surfaces and proper bonding between the concrete and prestressing wires.</p> |
