GFRP筋与煤矸石混凝土粘结性能试验

Experimental study on the bonding performance between GFRP reinforcement and coal gangue concrete

  • 摘要: 为研究不同影响因素对玻璃纤维增强树脂基复合材料GFRP (Glass fiber reinforced polymer)筋和煤矸石混凝土粘结性能的影响,进行了48个GFRP筋煤矸石混凝土试件的拉拔试验,分析了煤矸石取代率、GFRP筋直径、煤矸石混凝土强度、锚固长度等影响因素对GFRP筋与煤矸石混凝土粘结性能的影响。结果表明:GFRP筋和煤矸石混凝土试件的破坏形态有拔出破坏和劈裂破坏两种。GFRP筋与煤矸石混凝土的粘结-滑移曲线大致分3个阶段:上升段、下降段和残余段。随着煤矸石取代率的升高,极限粘结强度随之降低。在煤矸石混凝土基准强度C35组,煤矸石骨料取代率由0%增加到100%,极限粘结强度由5.5%下降至25.2%,高于煤矸石混凝土基准强度C50组的4.7%~21.2%;由于剪切滞后及泊松效应的影响,粘结强度随着筋直径的增大逐渐减小,直径16 mm的极限粘结强度大致为直径10 mm的77%;当锚固长度增加到一定值时,荷载不再增加,锚固长度从30 mm (2.5 d)增加到120 mm (10 d),极限粘结强度降低了22.89%。采用三段式粘结应力-滑移关系建立了GFRP筋煤矸石混凝土粘结滑移本构模型,为此类构件粘结锚固性能的研究奠定了理论基础。

     

    Abstract: To investigate the influence of different influencing factors on the bonding performance between glass fiber reinforced polymer reinforcement and coal gangue concrete, 48 GFRP reinforcement coal gangue concrete specimens were subjected to pull-out tests. The influence of factors such as coal gangue substitution rate, GFRP reinforcement diameter, coal gangue concrete strength, and anchoring length on the bonding performance between GFRP reinforcement and coal gangue concrete was analyzed. The results indicate that the failure modes of GFRP reinforcement and coal gangue concrete specimens include pull-out failure and splitting failure. The bond slip curve between GFRP reinforcement and coal gangue concrete can be roughly divided into three stages: ascent stage, descent stage, and residual stage. As the replacement rate of coal gangue increases, the ultimate bonding strength decreases. In the coal gangue concrete benchmark strengh C35 group, the replacement rate of coal gangue aggregate increases from 0% to 100%, and the ultimate bonding strength decreases from 5.5% to 25.2%, which is higher than the 4.7%-21.2% of coal gangue concrete benchmark strengh C50 group. Due to the influence of shear lag and Poisson's effect, the bond strength gradually decreases with the increase of reinforcement diameter. The ultimate bonding strength of 16 mm diameter is approximately 77% of that of 10 mm diameter. When the anchorage length increases to a certain value, the load no longer increases. The anchorage length increases from 30 mm (2.5 d) to 120 mm (10 d), and the ultimate bonding strength decreases by 22.89%. A three-stage bonding stress slip relationship was used to establish a bonding slip constitutive model for GFRP reinforced coal gangue concrete, laying a theoretical foundation for the study of bonding and anchoring performance of such components.

     

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