CFRC复合梁力学性能试验研究

Experimental study of mechanical properties of CFRC composite beams

碳纤维混凝土(CFRC)复合梁是在普通混凝土梁中掺入短切碳纤维,以此改善混凝土的性能.碳纤维弹性模量高,将其掺入混凝土中能改善混凝土的韧性并起到增强阻裂的效果.通过四点加载试验,研究普通混凝土梁与不同纤维层厚度、不同纤维长度的复合梁的弯曲破坏机理、荷载挠度行为、裂缝形态等.试验结果表明,在混凝土梁的受拉区掺入短切碳纤维可以有效改善其变形能力;碳纤维对混凝土裂缝扩展的抑制、裂缝形态的改善效果较好;纤维层厚75mm、纤维长度10mm的复合梁性能最优.最后提出了CFRC弯曲构件极限承载力的计算公式.

Carbon fiber reinforced concrete(CFRC)composite beam is a kind of concrete beam which is reinforced with short carbon fiber to improve the performance of concrete.CFRC toughness and crack resistance ability can be enhanced by high elastic modulus carbon fiber.The failure mechanism,load deflection behaviors,crack pattern of concrete beams and composite beams with different fiber layer thickness and fiber length are studied by four-point bending test.The results show that the deformation ability of concrete beams can be effectively improved by the short carbon fiber in the tension zone.The carbon fiber shows positive effect on restraining crack propagation and changing crack distribution in concrete matrix.Composite beam with 75 mm fiber layer thickness and 10 mm fiber length shows the best performance.Finally,the design formula for ultimate bearing capacity of CFRC bending member is proposed.