GFRP管约束竹筋细石混凝土组合杆力学性能试验

Experimental examination on mechanical properties of GFRP tube-encased bamboo reinforced fine stone concrete composite rods

在当前绿色发展、“双碳”目标、科技创新的多元化发展中,工程建设行业要实现“双碳”目标,需寻找合适的钢制品替代产品。竹材作为重要工程结构用材应时而发,很有必要研发“以竹代钢”的创新技术和产品。依据实际工程需求,提出一种玻璃纤维复合材料(GFRP)管约束大截面竹筋细石混凝土组合(GBCC)构件,替代薄壁钢管用作围栏承载立杆。GBCC构件力学性能良好、制作工艺简单、产品绿色低碳。为研究GBCC的基本受力性能和不同材料的协同工作状态,进行了12根GBCC短杆轴压破坏试验、7根长杆轴压稳定试验和10根长杆抗弯试验,并研究了GBCC杆力学性能的影响规律。结果表明:GBCC短杆轴压胀裂压溃破坏,长杆轴压失稳,长杆抗弯脆性断裂破坏;GBCC材料构成、含竹率、细石混凝土密实性、试件受力方向、竹筋缺陷均影响GBCC杆的受力性能;含竹率20%左右的GBCC试件能够达到甚至超过薄壁空心钢管试件的承载力和变形能力;GBCC长杆具有很好的弹性变形能力,基于试验结果构建了GBCC长杆抗压失稳极限承载力公式。

To achieve the goal of carbon neutrality by this mid-century is an urgent and arduous task.The emission reduction does not mean cutting production and the focus should be promoting a green transformation in economic development.In the current green strategy development and diversified development of scientific and technological innovation,the engineering construction industry needs to find the alternatives of steel products to achieve the“Dual Carbon”goal.As one of the important structural materials,bamboo material is desired to be developed through innovative technologies to replace steel materials.According to the actual project requirements,a glass fiber reinforced polymer(GFRP)tube-encased bamboo reinforcement fine-stone concrete composite(GBCC)member was proposed in this study,which was used to replace the thin-wall steel-tube as the bearing upright robs of the fence.GBCC rod had good mechanical properties,simple manufacturing process.To investigate the basic mechanical properties of GBCC and the cooperative working state of different materials,the influence law of mechanical properties of GBCC rob was investigated by conducting axial failure tests of 12 short rods,axial stability tests of seven long rods and bending tests of 10 long rods.The results showed that the failure mode of GBCC short specimens under axial compression was the bursting and crushing failures,the failure mode of the long specimens under axial compression was instability,and the failure mode of the long specimens subjected to bending-resistance was the brittle fracture failure.The material composition,bamboo content,concrete compactness,loading directions of specimen and defects of bamboo material all affected the mechanical performance of GBCC rods.The long GBCC rod had good elastic deformation ability.The GBCC specimens with about 20%bamboo content can reach or even exceed the bearing capacity and deformation capacity of the thin-walled hollow steel tube specimens.Based on the experimental results,the ultimate bearing capacity formula of the long GBCC rods under axial compression was established.