This paper uses the orthogonal test method to analyze various factors affecting the impermeability of concrete. By preparing carbon fibre reinforced concrete specimens and performing hydraulic pressure test on the specimens, this paper studies how various factors affect the impermeability of concrete. The test results show that the effects of carbon fibre and silica fume on the impermeability of concrete are significant. When C40 concrete was mixed with 0.5% carbon fibre, 0.019% methylcellulose, and 0.18% silica fume, the permeated height decreased from 5.7cm to 2.7cm, a decrease of 52.6%. On the other hand, carbon fibre length has no significant effect on the impermeability of concrete.
