桥墩冲刷破坏纤维水泥基修补材料试验研究

Experimental Study of Using Fiber-Reinforced Cementitious Material to Repair Bridge Pier Scour Damage

为研究用于混凝土桥墩冲刷破坏的修补材料,采用正交试验法,设计制作纤维水泥基修补材料并进行力学性能研究。在水泥基复合材料中加入pp纤维,采用低水胶比,进行纤维水泥基修补材料试配,将硅灰、粉煤灰、pp纤维和减水剂设为正交因素,根据各因素水平确定正交试验配合比,制备各组配合比试件并测试其抗折强度、抗压强度、耐磨性和抗冲击性,对试验结果进行对比分析。试验结果表明:配制的纤维水泥基修补材料具有优异的力学性能、耐磨性和抗冲击性;纤维和减水剂对修补材料施工性能影响较大;硅灰对修补材料性能有显著影响,增加硅灰掺量会提高力学性能、磨耗性和冲击韧性,但会降低延性指数;增加纤维掺量可以提高延性指数。将该修补材料运用于实际工程中,施工性能良好,修补结构表面无明显开裂、脱落等现象,对于原主体结构具有良好的保护性能。

To study the materials that can be used to repair the scour damage of concrete piers,the fiber-reinforced cementitious repair material was designed and prepared by the orthogonal testing method,to study the mechanical property of the material.The pp fiber was added to the cement-based composite material and the fiber reinforced cementitious material was prepared for trial with low water-cement ratio.The orthogonal factors include the silica fume,fly ash,pp fiber and water reducer,the mixing proportion for the orthogonal testing was determined in accordance with the level of each factor.Specimens made by different mixing proportion were prepared to test the bending strength,compressive strength,abrasion resistance and impact ductility,and the results of the testing were compared and analyzed.Results of the analysis demonstrate that the fiber reinforced cementitious repair material has excellent mechanical property,abrasion and impact resistance.The fiber and water reducer has great impact on the constructability of the repair material.Silica fume shows significant influence on the performance of the repair material,increasing the amount of silica fume can enhance the mechanical property,abrasion and impact resistance of the material,but decrease the ductility index.Increasing the amount of fiber can improve the ductility index.The repair material was used to a real engineering project.It shows good workability,no obvious cracks and spalling were observed on the surface of the structure repaired and the material can provide good protection to the original main structure.