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近几年来,一种新型预应力混凝土技术——后张无粘结预应力混凝土技术在我国得到了应用和发展。后张无粘结预应力混凝土,简称无粘结预应力,改变了通常后张法预应力施工方法。施工时无需预留孔洞以及张拉后灌浆等繁杂工序。而只是在预应力筋的表面涂上一层润滑防锈油脂,再裹上一层防护材料(如塑料等),经过这样处理后的预应力筋就称无粘结筋。浇筑混凝土前,无粘结筋同普通钢筋一样施工,按设计要求铺放和绑扎在模板内。待混凝土强度达到设计标号的70％以上时,即可进行张拉、锚固,从而完成全部
In recent years, a new kind of prestressed concrete technology—post-tensioned unbonded prestressed concrete technology has been applied and developed in China. The post-tensioned unbonded prestressed concrete, referred to as unbonded prestress for short, has changed the usual post-tensioned prestressed construction method. It is not necessary to reserve holes, post-tensioning grouting and other complicated procedures during construction. Only the surface of the prestressed tendon is coated with a layer of lubricating rust-preventing grease, and then a protective layer (such as plastic) is wrapped. After this treatment, the prestressed tendons are called non-bonded tendons. Before the concrete is poured, the unbonded tendons are constructed in the same way as ordinary steel reinforcements, laid out according to the design requirements and bound in the formwork. When the concrete strength reaches more than 70% of the design label, it can be tensioned and anchored to complete all