市政给排水管道修复用改性材料抗折与粘接强度研究

Study on the flexural strength and adhesive strength of modified ma-terials for the repair of municipal water supply and drainage pipelines

研究了不同集胶比、氧化镁与磷酸盐的质量比、硼砂掺量和水胶比条件下磷酸镁水泥基材料的抗折粘接强度,并对破坏形式进行了统计分析。结果表明,在不同的养护时间下,磷酸镁水泥基材料的抗折粘接强度都会随着集胶比增加逐渐减小。随着氧化镁与磷酸盐的质量比增加,不同养护龄期下磷酸镁水泥基材料的抗折粘接强度都表现为先增加后减小。在相同的硼砂掺量下,龄期越高则对应的磷酸镁水泥基材料的抗折粘接强度越大。随着水胶比增加,不同养护龄期下磷酸镁水泥基材料的抗折粘接强度都表现为逐渐减小。此外,在相同水胶比下,龄期越长则磷酸镁水泥基材料的抗折粘接强度越大。在修补市政给排水管道时,磷酸镁水泥基材料的断口形貌主要包括:沿着界面破坏、MPC优先破坏和旧基体优先破坏。

The flexural bonding strength of magnesium phosphate cement-based materialswas studied under different aggregate ratio,mass ratio of magnesium oxide to phosphate,borax content and water-binder ratio,and the failure forms were statistically analyzed.The results showed that the flexural bonding strength of magnesium phosphate cement-based materials gradually decreased with the increase of the aggregate ratio under different curing time.With the increase of the mass ratio of magnesium oxide to phosphate,the flexural bonding strength of magnesium phosphate cement-based materials at different curing ages increased first and then decreased.Underthe same content of borax,the higher the age,the greater the flexural bonding strength of the corresponding magnesium phosphate cement-based material was.With the increase of water-binder ratio,the flexural bonding strength of magnesium phosphate cement-based materials at different curing ages decreased gradually.In addition,under the same water-binder ratio,the longer the age,the greater the flexural bonding strength of magnesium phosphate cement-based materials was.When repairing municipal water supply and drainage pipes,the fracture morphology of magnesium phosphate cement-based materials mainly included:damage along the interface,MPC priority damage and old matrix priority damage.