功能梯度混凝土层间界面黏结性能试验研究

Experimental research on the interface bonding performance of ECC-RC functionally gradient concrete

采用国产PVA纤维作为增韧材料制备ECC,考虑混凝土强度等级、界面处理方式及ECC厚度三种参数设计制作了12组ECC-RC功能梯度混凝土试块。通过双面剪切试验,研究了ECC-RC功能梯度混凝土的层间界面黏结性能及上述三参数对其层间界面黏结性能的影响。试验结果表明:界面处理方式对试块的破坏形态有显著影响;功能梯度混凝土的层间界面黏结强度随混凝土强度等级的提高而增加;采用人工凹槽处理试块层间界面可显著提高功能梯度混凝土的层间界面黏结强度;当试块层间界面未经处理或采用人工凹槽处理时,试件的平均层间界面黏结强度随ECC厚度的增加而提高。试验结果可为ECC-RC功能梯度混凝土试件的设计及使用提供试验依据。

Twelve series of ECC-RC functionally gradient concrete specimens were tested by two-sided shearing experiment to investi- gate their interface bonding performance.The ECC used was newly developed engineered cementitious composites using domestic polyvinyl alcohol（PVA） fiber along with other local ingredients, such as fly ash, cement and sand.The effects of concrete strength grade, interface treatment method and thickness of ECC on the interface bonding performance were also evaluated.Results show that interface treatment method has a significant impact on the failure mode of specimens.In addition, interface bonding strength of ECC-RC functionally gradient concrete improves as concrete strength grade increases and the use of artificial groove treatment method can improve the interface bonding strength of functionally gradient concrete.For the specimens with untreated interface or treated interface using artificial groove treatment method,the average interface bonding strength of the specimens increases with the increase of thickness of the ECC.The obtained results hopefully provide experimental reference for the design and application of the ECC-RC functionally gradient concrete members.