高活性偏高岭土的研究

High reactivity metakaolin

在650℃～800℃下煅烧高岭土,制得偏高岭土(MK),MK呈现热力学介稳状态,含有大量无定形的二氧化硅和氧化铝.采用正交试验讨论煅烧温度、煅烧时间和高岭土的SiO2和A12O3含量对MK活性的影响.MK具有高火山灰活性,正逐渐成为新一代高性能矿物掺合料.内掺10%时,其活性指数达到114,比硅粉高11.8%.使用MK作为矿物掺合料可以配制高强混凝土,MK掺量为10%,水胶比0.375,混凝土的28d抗压强度为73.9MPa.在碱激发剂作用下,使用MK制备土壤聚合物,土壤聚合物具有无定形或半结晶结构,早期强度较高,60℃条件下养护3小时,抗压强度达到55.8MPa,室温下1d,抗压强度达到58.5MPa.

Metakaolin was prepared with kaolin by heat - treated technique that contained a great deal of amorphous SiO2 and Al2O3, Affecting factors for the activity of metakaolin, burning temperature, burning time and contents of SiO2 and Al2O3, were discussed through orthogonal tests. Activity index of Metakaolin was 114 that was larger by 11. 8% than that of silica fume, Metakaolin with high pozzolanic activity, a new kind of mineral admixture, can be used to prepare high strength concrete. The compressive strength of MK concrete with water - cementitious materials ratio equal to 0. 375 was 73.9 MPa which contained 10 % MK, Geopolymer with amorphous to semi- crystalline structure was prepared with metakaolin activated by alkali activators. Its compressive strengths in early time were high reaching 55.8MPa cured at 60℃ for 3 hours and 58,5 MPa cured at room temperature for 1 day,