循环流化床脱硫灰基矿物掺合料的制备及性能研究

Preparation and performance research of circulating fluidized bed combustion desulfurization ash based new mineral admixture

利用循环流化床脱硫灰复合矿渣制备矿物掺合料,通过活性指数判定矿物掺合料作为粉煤灰或矿粉使用的可行性,评定矿物掺合料的抗硫酸盐侵蚀性能。研究表明:脱硫灰-矿渣-水泥体系的力学强度随脱硫灰掺量的上升而下降;在脱硫灰-矿渣掺量为50%,脱硫灰掺量不超过25%时,复合掺合料可达到S75矿粉的使用标准;改性灰∶矿渣=1∶1时,复合掺合料可达S95矿粉的使用标准。脱硫灰-矿渣掺量为30%时,试样28d活性指数均超过了70%,其中改性灰FS-8试样可达98%。脱硫灰∶矿渣=1∶3时体现出复合水化叠加效应。脱硫灰降低了硬化浆体后期的抗蚀系数,复合矿渣或脱硫灰改性均可改善硬化浆体抗硫酸盐侵蚀能力。SEM照片表明:引入脱硫灰后试样水化产物中AFt增多,脱硫灰掺量增加,水化试样的密实度降低。

New mineral admixture was prepared by circulating fluidized bed combustion desulfurization ash compound granulated blast furnace slag.To determine the feasibility of its use as fly ash or slag by activity index, sulfate resistance of the new mineral admixture was evaluated.The results showed that the mechanical strength of cement-desulfurization ash-slag system decreased with the increase of circulating fluidized bed combustion desulfurization ash.While the ash-slag content was 50%, desulphurization content did not exceed 25%, the composite admixture was up to S75 slag using standard.While the modified desulfurization ash：slag=1：1 ,the composite admixture was up to S95 slag using standard.While the ash-slag content was 30%, the 28d activity index of all samples was more than 70%, which reached the use standard of fly ash.The activity index of modified desulfurization ash FS-8 was up to 98%.While ash：slag=1：3, the hydration additive effect reflected out.The desulfurization ash reduced the sulfate resistance of hardened paste, while complex slag or ash modification could improve the sulfate resistance.SEM photos showed that the hydration products of AFt crystals increasing AFt in after the introduction of desulfurization ash.With the desulfurization ash content increased, the density of hydration sample reduced.The hydration products increased and the paste structure become more dense after desulfurization ash be modified.