磷酸镁嵌入式纤维筋加固系统界面试验研究  

Experimental study of the interface of magnesium phosphate cement near-surface mounted GFRP system

作　　者：刘周强 张力文[1] 孙卓[1] 李晶[1] 邹志伟 LIU Zhouqiang;ZHANG Liwen;SUN Zhuo;LI Jing;ZOU Zhiwei(School of Civil Engineering, Guangzhou University, Guangzhou 510006, China)

机构地区：[1]广州大学土木工程学院,广东广州510006

出　　处：《哈尔滨工程大学学报》2020年第9期1287-1294,共8页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(51608137);广州大学研究生创新能力培养计划(2018GDJC-M29).

摘　　要：传统嵌入式复合增强纤维加固系统常以环氧树脂作为粘结剂,其存在造价高、易老化、耐高温性能差、低温固化慢等问题。为改善环氧树脂的上述问题,采用价格较低、快凝快硬、耐久、低温易固化的磷酸镁水泥,用于混凝土桥梁结构的快速修补加固。本文采用单剪搭接拉拔试验,研究了养护龄期和硅灰掺量对MPC-NSM-GFRP加固系统粘结界面性能的影响,分析了不同养护龄期和硅灰掺量下试件的破坏模态、荷载-位移曲线和局部粘结应力-滑移曲线。研究结果表明:MPC龄期敏感性较低,在较短龄期(2 d)时MPC粘结性能优于环氧树脂粘结剂试件;达到强度要求情况下,MPC更有利于快捷、高效的工程加固需求;硅灰掺入后的微集料效应及其与氧化镁(MgO)的水化物作用可以改善MPC的粘结性能,当硅灰掺量超过一定值(6%)时,MPC粘结性能随硅灰的增加显著降低。Epoxy resin is commonly used as a binder in the traditional near-surface mounted fiber-reinforced polymer(NSM-FRP)reinforcement system.However,epoxy resin has many disadvantages,such as high price,easy degradation,poor high-temperature resistance,and slow curing at low temperatures.To solve the aforementioned problems,magnesium phosphate cement(MPC)has been gradually used in the rapid reinforcement of concrete bridges.MPC has many advantages,such as low price,good durability,good high-temperature resistance,and fast curing at low temperatures,compared with epoxy resin.In this study,the effects of curing age and silica fume content on the interface bonding properties of the MPC-NSM-GFRP reinforcement system have been investigated by a single-lap-joint shear pullout test.The failure modes,load-displacement curves,and local bonding stress-slip curves of the specimens under different curing ages and silica fume contents were analyzed.The research results proved that:MPC has a low sensitivity to the curing age,and the bonding property of MPC is better than that of epoxy resin binder in the short curing age(2 days).MPC is more beneficial to the needs of fast and highly efficient engineering reinforcement under the condition of meeting the strength requirement.The bonding property of MPC can be improved by the microaggregate effect of doped silica fume and the action of the hydrate of silica fume and magnesium oxide.When the content of silica fume exceeds a certain value(6%),the bonding performance of MPC significantly decreases with the increase in silica fume content.

关 键 词：嵌入式 磷酸镁水泥 复合纤维筋 养护龄期 硅灰 微集料 粘结界面 

分 类 号：TU528.45[建筑科学—建筑技术科学]