Abstract: Compared with other fibers, ceramic fiber is characterized by high temperature resistance and exce- llent impact resistance. In order to promote the application of ceramic fiber in the field of concrete materials, the impact resistance of ceramic fiber modified concrete (CRFMC) with different fiber volume content (0.1%, 0.2%, 0.3%) after different high temperatures (200, 400, 600, 800 ℃) is studied with high temperature test and separated Hopkinson pressure bar test. The modification mechanism of ceramic fiber is analyzed by observing the micromorphology of CRFMC after different high temperature test. The results show that ceramic fiber can improve the impact resistance of concrete after high temperature test, and the optimal content of ceramic fiber is 0.2%. With this fiber content, the damage degree of CRFMC is the lightest, and the dynamic compressive strength, dynamic peak strain and impact dissipation energy are the maximum. With the rise of temperature, the damage severity degree, dynamic compressive strength and impact dissipation energy of CRFMC first decrease and then increase, and the dynamic peak strain increases. The dynamic peak strain of CRFMC shows a thermoplastic effect. Ceramic fiber still maintains good shape after high temperature test, and is not decomposed or fused. The improvement effect of ceramic fiber on dynamic compressive strength and impact dissipative energy of concrete at high temperature (400~800 ℃) is better than that at 20 ℃.

Key words: concrete, ceramic fiber, high temperature, impact resistance