Study on cable grouts of post-prestressed concrete
(Central Research Institute of Building and Construction CO,. LTD. MCC Group, Beijing 100088)
Gao Hanqing Shao Zhengming Zhong Chaoming Zhong Xiaolin
Abstract: This paper generally reviewed authoritative standards and specifications about cable grouts on post-prestressed concrete at home and abroad. A more comprehensive and stricter referenced performance index about cable grouts was proposed based on the amelioration of TB/T3192-2008. Under the guidance of this performance index, an experimental program was carried out based Taihang cement and CGM-11, which is a kind of cable grouting agents. An apparatus named Shrinkage-Cone was employed to assess the volume stability of cable grouts made from CGM-11, due to its ability to straightly test the volume change of cable grouts from fresh state to hardened state. The experimental results showed that cable grouts prepared by CGM-11 had excellent performance.
Key word: TB/T3192-2008; CGM-11 cable grouting agents; Shrinkage-Cone; volume stability
0 引言
后张法有粘结预应力混凝土结构凭借其可靠的耐久性，在诸如桥梁、高层建筑等大跨度板梁结构中有着广泛的应用。孔道灌浆料则在该结构中承担着保护预应力钢筋不受有害离子侵蚀，以及使预应力钢筋和周围混凝土结为整体协同工作的重任。因此，孔道灌浆料性能好坏直接关系到后张法有粘结预应力混凝土结构的耐久性。
关于孔道灌浆料的相关规范，国内在2008年之前主要有JTJ041-2000《公路桥涵施工技术规范》1和GB50204-2002《混凝土结构工程施工质量验收规范》2，之前的许多研究工作也都是参照二者进行的。但是，这些规范针对孔道灌浆料性能的相关规定比较落后，诸如：强度不低于30MPa、泌水率不得超过3%、自由膨胀率应小于10%等等，这些指标要求早已不能满足实际工程对孔道灌浆料性能的要求。铁道部于2008年颁布实施的TB/T3192-2008《铁路后张法预应力混凝土梁管道压浆技术条件》3则是目前国内针对孔道灌浆料较为全面的技术规范。
国际上关于孔道灌浆料较先进的规范主要是美国后张预应力协会（Post Tensioning Institution）发布的规范4 (简称PTI 规范)和佛罗里达交通部（Florida Department Of Transportation）发布的规范5（简称FDOT规范），它们均是以ASTM有关测试标准为基础的规范。其中，FDOT规范相比而言更为全面，它对孔道灌浆料的3h毛细泌水率、抗渗性、氯离子含量都有严格的规定。
本文主要结合FDOT规范相关指标要求，对TB/T3192-2008进行改进，从而提出了更为严格、全面的孔道灌浆料性能改进指标，并在此改进指标的指导下进行了CGM-11孔道压浆剂与太行水泥的配比试验研究；进而在此基础上采用德国先进仪器shrinkage cone测试仪对孔道灌浆料的体积稳定性进行了更为细致深入的研究。
