Abstract: Metakaolin as a pozzolanic activity material is an excellent substituted cement material since it cause less energy consumption and environment pollution during calcining and can improve some properties of Portland cement such as strength and durability when it is blended in cement. In recent years, many researchers devoted themselves to research the pozzolanic of metakaolin. In this paper, the optimum calcination temperature and time, the influence factors on the activity and the methods that test kaolin properties and metakaolin activity were summarized. According to the predecessors ' research results, the optimum calcination temperature and time are affectd by the mineralogy composition, crystallite and kaolinite content , among which the most prominent influence factor on the calcined kaolin 's activity is the crystallite. The kaolin's properties can be analyzed by the methods including XRD, TG-DTA and IR. The metakaolin 's properties can be analyzed by the Frattni, Chapelle, the electrical conductivity and the strength activity index test, among which the most accurate test methods are the Frattni and strength activity index test.

Key words: kaolin;activity;calcination temperature;crystallinity