水泥土组成矿物的热重-热力学模拟联用分析

Compositional Minerals of Cemented Soil by Combined Thermogravimetry and Thermodynamic Modelling

针对常规微观测试技术难以准确分析水泥土矿物组成的问题,提出联用热重分析与热力学模拟的方法,综合分析水泥土的矿物组成与过饱和度(SI).制备了水泥与土干重比为1∶9的基准水泥土,以及炼钢厂回转炉底灰(SLA)替代5%~100%水泥的改性水泥土,测试其无侧限抗压强度,并采用所提出的方法分析混料后5~672 h内水泥土关键矿物组成的赋存特征,以探明SLA对水泥土性能的改性机理.结果表明:热力学模拟可以定量表征水泥土矿物组成的赋存状态,有效弥补热重分析难以区分吸热峰重叠矿物的不足;SLA主要通过提升水泥土孔隙液中Ca(OH)_(2)的SI来提升水泥土的长期强度.

The mineralogical study on the cemented soil using conventional micro‑analysis methods is inaccurate due to the compositional complexity.A method of thermogravimetry combined with the thermodynamic modelling,which calculated the mineral supersaturation index(SI)based on pore solution composition was proposed.The dry mass ratio of cement/soil of the referenced cemented soil specimen was 1/9,and the modified specimens were prepared by using the sintered limestone ash(SLA)from the steel‑making industry to replace cement in fractions of 5%-100%of the referenced mass.The unconfined compressive strength of all specimens was tested and the representative specimens were then selected for quantitative analysis of the critical minerals using the proposed method within the timeframe of 5-672 h after the mixing.The results demonstrate that the thermodynamic modelling provides direct implications of the occurrence state of the minerals of the cemented soil,which complementes the defect of the endotherms overlapping of thermogravimetry.Meanwhile,the long‑term unconfined compressive strength improvement is benefitted from the increased Ca(OH)_(2) SI in the pore solution with appropriate SLA addition.