碱激发偏高岭土基地质聚合物的制备及抗压强度研究

为了响应“双碳”政策节能减排的号召,本文采用偏高岭土和高炉矿渣为原材料制备地质聚合物。以抗压强度为指标优化制备条件,探讨确定影响地质聚合物强度的因素。通过正交试验确定偏高岭土基地质聚合物的最佳配比,通过热重和XRD分析不同温度煅烧的偏高岭土组分。研究结果表明,在高岭土煅烧温度为800 ℃时,偏高岭土基地质聚合物的最佳配合比为氢氧化钠与硅酸钠的质量比为6.5∶1,激发剂的质量掺量为14.2%,其28 d抗压强度能达到46.6 MPa。偏高岭土基地质聚合物抗压强度随激发剂的掺量增加而增大,随氢氧化钠与硅酸钠的质量比的增大先增大后减小,随高岭土煅烧温度的升高先增大后减小。

Preparation and Compressive Strength of Geopolymer Based on Alkali Activated Metakaolin

In response to the “carbon peak and neutrality” policy of energy saving and emission reduction, in the present paper, geopolymers were prepared with metakaolin and blast furnace slag as raw materials. The compressive strength was used as the index to optimize the preparation conditions and to explore the factors affecting the strength of geopolymer based on metakaolin. The optimum mixing ratio of geopolymer was determined by orthogonal test. The metakaolin fractions calcined at different temperatures were analyzed by thermogravimetry and XRD. The research results show that when the calcining temperature of kaolin is 800 ℃, the optimum mixing ratio of geopolymer based on metakaolin is that the mass ratio of sodium hydroxide to sodium silicate is 6.5∶1 and the mass fraction of activator is 14.2%. Under these conditions, the 28 d compressive strength of the geopolymers reaches 46.6 MPa. The compressive strength of the geopolymer based on metakaolin increases with the addition of the mass fraction of activator, and increases first and then decreases with the increase of the mass ratio of sodium hydroxide to sodium silicate, and increases first and then decreases with the increase of kaolin calcination temperature.