碳纤维无胶螺旋缠绕加固混凝土柱轴压试验研究

Experimental study on concrete columns strengthened with non-adhesive carbon fibre spirals under axial compression

为解决纤维增强复合材料（FRP）因树脂类胶黏剂受热失效而难以有效提供侧向约束的问题,采用纤维条带无胶黏结螺旋缠绕的加固方法,对碳纤维螺旋缠绕加固混凝土柱（CSSC）进行常温下的单调轴压试验。采用粒子图像测速（PIV）技术测量应变,研究碳纤维层数、纤维条带宽、水泥浆设置及中部搭接等因素对其力学性能的影响。试验结果表明：CSSC试件比无加固混凝土的承载力提高20%以上,变形能力提高1～2倍,且破坏全过程无爆裂。CSSC试件的轴压性能随纤维层数的增加而显著提高;纤维条带宽增加会引起纤维与环向倾斜夹角的增加,不利于提高CSSC试件承载力;水泥浆设置在核心混凝土柱与纤维之间,有利于提高CSSC试件承载力;水泥浆设置在纤维外层,有利于增加试件横向极限应变。

Fibre-reinforced polymer（ FRP） has little effect on confining concrete in fire because of the resinae adhesive invalid,a new strengthening method for strengthened concrete members with non-adhesive carbon fibre spirals was proposed by the third author in order to alleviate this problem. This paper presents an experimental study on the axial compression behavior of this carbon fibre spirals strengthened concrete column（ CSSC） at room temperature. The particle image velocimetry（ PIV） technique was used to measure the deformation. The test program considered the effects of the number of fibre layers,the width of fibre strap,the position of grout and fibre connection. The test results show that compared with the corresponding plain concrete column,the bearing capacity of CSSC is 20%higher,and the ductility increases by 1 ~ 2 times. The failure process of CSSC columns reveals no bursting. The mechanical properties of CSSC are improved with an increasing number of fibre layers. A wider fibre strip width may cause a large angle between the fiber direction and the horizontal,which decreases the bearing capacity of CSSC. It would increase the bearing capacity of CSSC if grout attached to the interface between concrete and fibres. Attaching grout to the outside of fibres improves the transverse ultimate strain of CSSC.