BFRP筋与低碱度硫铝酸盐水泥混凝土粘结性能试验

Experimental investigations on bonding performance between BFRP bars and low alkalinity sulphoaluminate cement concrete

为研究玄武岩纤维增强聚合物复合材料(Basalt fiber reinforced polymer,BFRP)筋与低碱度硫铝酸盐水泥混凝土的粘结性能,对共90个粘结试件进行中心拉拔试验,研究了筋材表面形貌、混凝土强度等级等因素对粘结性能的影响。试验结果表明:对筋材表面进行喷砂、缠绕纤维和螺纹处理能显著提高粘结性能,深螺纹环氧树脂BFRP筋与65 MPa低碱度硫铝酸盐水泥混凝土的粘结强度高达39.09 MPa,远大于光滑BFRP筋的13.32 MPa。强度等级对BFRP筋-低碱度硫铝酸盐水泥混凝土粘结试件的粘结强度的影响更明显,此外BFRP筋与低碱度硫铝酸盐水泥混凝土粘结性能高于普通硅酸盐混凝土。最后,通过Cosenza-Manfredi-Realfonzo(CMR)模型和修正后的Bertero-Popov-Eligehausen(mBPE)模型对BFRP筋-混凝土粘结试件的粘结滑移(τ-s)曲线进行拟合,发现CMR模型对粘结滑移曲线的上升段拟合效果较好,清晰准确地反映了其粘结-滑移本构关系,为研究BFRP筋增强硫铝酸盐水泥混凝土结构的力学性能提供了关键理论依据。

In order to study the bonding performance between basalt fiber reinforced polymer(BFRP)bars and low alkalinity sulphoaluminate cement concrete,a total of 90 bonding specimens were tested by central pullout test.The effects of surface morphology of BFRP bars and concrete strength grade on the bonding performance were studied.The experimental results show that sand blasting,fiber winding and ribbed treatments on the surface of BFRP bars can significantly improve the bonding performance,the bond strength between deep ribbed epoxy resin BFRP bar and low alkalinity sulphoaluminate cement concrete with strength grade of 65 MPa is as high as 39.09 MPa,which is much higher than 13.32 MPa of smooth BFRP bar.The effect of strength grade on bond strength of BFRP bar/low alkalinity sulphoaluminate cement concrete is more obvious.In addition,the bonding performance between BFRP bars and low alkalinity sulphoaluminate concrete is higher than that of ordinary portland concrete.Finally,the CMR and mBPE models were used to fit the bond-slip(τ-s)curve of BFRP bar-concrete bond specimens.It is found that the fitting result of CMR model for the ascending segment of the bond-slip curve is better,which clearly and accurately reflects the bond-slip constitutive relationship between BFRP bar and concrete,and provides a key theoretical basis for investigating performance of BFRP-reinforced sulphoaluminate cement concrete structures.