聚丙烯纤维灌浆料及其钢筋套筒连接受力性能试验研究

Experimental study on mechanical properties of polypropylene fiber grouting material and its rebar sleeve connection

为改善装配式结构节点的力学连接性能,对聚丙烯(PP)纤维灌浆料进行材性性能及其钢筋套筒连接接头的力学性能研究。选用不同掺量、长度PP纤维的灌浆料进行力学性能试验,确定PP纤维最佳掺量(占普通(JZ)灌浆料的体积比)和长度分别为0.5%和9 mm。以JZ灌浆料为对照组,设置了4d、6d、8d(d为钢筋直径)3种锚固长度的套筒接头试件并进行单向拉伸试验,采用光纤光栅传感器(FBG)和应变片两种测试方法研究PP纤维灌浆料下的粘结应力分布。结果表明:PP纤维增强灌浆料钢筋套筒的最小锚固长度在6d以上;PP纤维能够有效改善接头韧性,增强了套筒的粘结锚固效果,提高了筋粘结应力分布均匀程度,使其呈"马鞍形"或"斜梯型"分布;FBG传感器与应变片所得结果基本一致,FBG传感器所采集的应变数据精度高于应变片。

To improve the mechanical connection performance of fabricated structural joint,the material properties of polypropylene(PP)fiber grouting material and the mechanical properties of its rebar sleeve joint were studied.The mechanical properties of grouting material with different PP fiber contents and length were tested.The optimum content(Volume ratio to ordinary(JZ)grouting material)and length of PP fiber is 0.5%and 9 mm,respectively.Taking JZ grouting material as control group,the anchorage length of 4 d,6 d and 8 d(d is the diameter of bar)was set and the uniaxial tensile test was carried out.The bond stress distribution of PP fiber grouting material was also studied by using Bragg Grating sensors(FBG)and strain gauge.The results show that:The minimum anchorage length of rebar sleeve of PP fiber reinforced grouting material is more than 6 d;PP fiber can effectively improve the joint toughness,enhance the bond anchorage effect of the sleeve,and improve the uniform distribution of the bond stress of the reinforcement,which shows“saddle”or“inclined ladder”distribution;the results of FBG sensor and strain gauge are basically consistent,and the accuracy of strain data collected by FBG sensor is higher than that of strain gauge.