后张法预应力扁管孔道灌浆质量控制

摘要：后张法有粘结预应力与后张法无粘结预应力相比较，具有设计强度高、延性好的优点，可用于人防地下室以及抗震设防烈度为9°的地区和一级框架构件，取得了越来越广泛的应用。在板类构件中，由于受板厚的限制，预应力矢高通常较小，实践中往往通过配置扁形金属波纹管的措施来尽量加大预应力矢高。扁管由于孔道间隙较小，较圆管更容易出现堵塞等问题，文章对后张法预应力扁管孔道灌浆存在的问题进行了系统的分析，并就如何加强质量控制提出了建议。

关键词：后张法；扁管；孔道灌浆；质量控制

Abstract:ZhangFaYou after unbonded prestressed concrete with unbonded prestressed after a method, in comparison with high strength and ductility design of the advantages and can be used for civil air defence basement and seismic fortification intensity 9 ° to the area and level 1 framework components, made more and more widely. The board in the kinds of members, as thick the limit, prestressed with same smaller usually, practice often through the configuration oblate corrugated metal pipe measures to try to increase the high prestressed bolts. Flat tube because clearance through small, round pipe is more likely to have up and so on the problem, this paper a method after prestressed flat tube passes grouting the existing problem of the analysis of the system, and how to strengthen quality control was put forward.

Keywords: This method; Flat tube; Passageways grouting; Quality control

1. 引言

预应力灌浆主要有以下几点作用：1、水泥浆包裹预应力筋形成密闭空间，保护预应力筋免受腐蚀，保证结构或构件的安全寿命。2、预应力筋与构件混凝土良好结合形成有粘结，控制使用阶段的裂缝间距和宽度，消除端部锚具在反复荷载作用下出现应力变化导致疲劳破坏的可能性。

预应力筋张拉后处于高应力状态，对腐蚀非常敏感，灌浆是对预应力筋的永久性保护措施。如果灌浆不密实，水泥浆无法完全裹住预应力筋，则钢筋在高应力状态下锈蚀极易发展，导致预应力筋与混凝土之间的粘结力降低，协同工作能力下降，受力性能也向无粘结预应力混凝土构件转变。同时构件开裂后的挠度变大，极限承载力降低，使得预应力结构的安全寿命和使用可靠性受到威胁。针对这些问题，本文进行系统的分析并提出解决办法。

2. 灌浆存在的质量通病

2.1孔道成形质量问题