关键词: 杂散电流, 氯离子, 超高性能混凝土, 胶材类型, 损伤深度, 耐蚀性能

Abstract: To study the durability of ultra-high performance concrete (UHPC) under stray current environment, the effects of environmental type, chloride ion concentration and cementing material type on the corrosion morphology, ultrasonic velocity loss rate, damage depth, porosity and strength loss of UHPC under stray current environment were studied by electromigration accelerated corrosion test. The results show that UHPC specimens first generate cracks and spalling on the surface under stray current environment. With the increase of time of impressed current, the damage develops from the surface to the inside, and the internal fibers are seriously corroded and separated from the matrix. Under stray current environment, the damage depth of UHPC increases with the increase of time of impressed current approximately in a quadratic function. In the absence of chloride ion environment or less than 1% (mass fraction) of chloride ion concentration, the effect on the damage depth of UHPC is not significant, but with the increase of chloride ion concentration, the effect gradually becomes significant. The damage depth of UHPC at 3% chloride ion concentration is twice as large as that at 1%. Under the same conditions, the denser the UHPC is, the stronger the ability to resist stray current damage is. Adding phosphorus slag powder or fly ash to UHPC helps to enhance its corrosion resistance.

Key words: stray current, chloride ion, ultra-high performance concrete, cementing material type, damage depth, corrosion resistance