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针对混凝土表面粗糙程度对纤维布加固性能影响的研究不多的现状,采用数显干分表仪器并结合分形理论,对混凝土黏结面进行量化处理,结果表明分形维数可以作为量化评定混凝土黏结面粗糙程度的一个参数。在此基础上分析氯盐环境下粗糙度对混凝土界面力学性能的影响。试验结果表明:混凝土表面越粗糙,抗剪切能力越强,界面破坏越延迟,界面能越大。不同粗糙度界面有效传递距离为100~120 mm,界面越粗糙,有效传递距离越大,黏结性能越好,粗糙度f5的试件比粗糙度f0的试件黏结强度提高78%,极限位移提高200%。氯盐环境下混凝土与碳纤维复材界面应力滑移曲线中,界面越粗糙,脆性区间越长,材料反映的脆性性质越多,而进入塑性阶段,6种界面的黏结滑移曲线均以不同斜率下降,最终以0.6~1.0 mm不等的滑移值撕裂破坏。
In view of the fact that the surface roughness of concrete has little effect on the reinforcing performance of fiber cloths, a digital dry-score instrument and a fractal theory are used to quantify the concrete bonding surface. The results show that the fractal dimension can be used as a quantitative assessment of the bonding surface of concrete. A parameter of roughness. Based on this, the effect of roughness on the interfacial mechanical properties of concrete in the environment of chloride salt was analyzed. The test results show that the rougher the concrete surface is, the stronger the shear resistance, the more delayed the interface failure and the larger the interface energy. The effective transmission distance of different roughness interfaces is 100~120 mm. The rougher the interface, the larger the effective transmission distance, the better the bonding performance. The bond strength of the specimen with roughness f5 is 78% higher than the roughness f0, and the ultimate displacement is improved. 200%. Under the chloride salt environment, the interface stress-slip curves of concrete and carbon fiber composite materials show that the rougher the interface, the longer the brittle range, and the more brittle nature of the material, while entering the plastic stage, the adhesion slip curves of the six kinds of interfaces have different slopes. Decline, eventually tearing and breaking with a slip value ranging from 0.6 to 1.0 mm.