用单螺杆挤出机制备缓凝砂浆包裹钢筋的研究

Preparation of Postponed-Set Mortar Wrapped Steel Strand by Using Single-Screw Extruder

用单螺杆挤出机实现了缓凝砂浆连续包裹预应力钢绞线.基于缓凝砂浆的动力学性质，建立了缓凝砂浆螺旋输送模型；研究了缓凝砂浆在单螺杆挤出机中的流动情况.结果表明，当螺杆转速为122-220 r/min时，缓凝砂浆可实现连续输送、挤出和包裹；用单螺杆挤出机可得到包裹缓凝砂浆并外覆塑料护套的预应力钢绞线.

Postponed-set mortar（PSM） was successively wrapped on prestressed strand by making use of a single-screw extrusion method. Based on the experimental dynamic behavior study of PSM, the screw conveying model of PSM as Bingham liquid was established, and the flow of PSM in the single-screw extruder was studied. When the screw revolutions were within 122-220 r/min, the continuing conveying, extruding and wrapping for PSM could be achieved. The prestressed concrete strand wrapped with PSM was obtained with polyethylene sheath by using the machine.