关键词: 高岭土原矿;偏高岭土;活性;水泥砂浆;抗压强度

Abstract: The characterization analysis on the kaolin clay originated from Lingshou country Hebei province was performed by the X ray diffraction (XRD),Thermogravimetric and differential thermal analysis(TG/DTA) method.Then they were calcined in a programmable laboratory furnace for producing pozzolanic metakaolin,which was heated from the ambinent temperature to 550,650,750 and 850 ℃ for 1,2 and 3 h respectively.The activity of a series of metakaolin were tested by strength activity index test method thus assessing the potential that they become substituted cement materials.The results show that the activity of metakaolin by heating kaolin clay at 650 ℃ and 3 h is most optimal,for instance,the 28 d compressive strength of cement motar with 20％ replacement of cement can attain 90％ of strength value of pure cement mortar.

Key words: kaolin clay;metakaolin;activity;cement mortar;compressive strength