镍渣—粉煤灰基地质聚合物力学性能及耐久性能的研究

作为新型胶凝材料，地质聚合物应用前景广阔，而利用镍渣制备地质聚合物对实现固废综合利用有重要意义。通过硅酸钠和氢氧化钠复合碱溶液活化制备了镍渣—粉煤灰基地质聚合物，探讨了粉煤灰掺量对地质聚合物力学性能、抗冻性能、抗海水侵蚀性能的影响，并结合XRD、SEM及孔结构分析等手段阐明变化规律。结果表明：① 粉煤灰的引入，提高了地质聚合物的强度；当粉煤灰掺量为10%时，力学性能最优，7、28 d抗压强度分别为37.2、42.5 MPa，相比空白组试样分别提高了21.97%和17.40%。② 适量粉煤灰的掺入能够进一步降低地质聚合物在冻融循环、干湿循环中的抗压强度损失及质量损失。当掺入10%粉煤灰时，50次冻融循环后试样的抗压强度损失率、质量损失率分别为24.7%、14.9%，50次干湿循环后的抗压强度损失率为21.5%。③ 粉煤灰对碱激发的反应有益，增加了反应产物；同时，粉煤灰更小的颗粒粒径，对地质聚合物提供了更好的填充效应。研究结果可为镍渣—粉煤灰基地质聚合物的开发及相关耐久性能问题的探索提供参考。

Study on Mechanical and Durability Properties of Nickel Slag and Fly Ash Based Geopolymer

As a new cementing material,geopolymer has a broad application prospect,and the preparation of geopolymer from nickel slag is of great significance to realize the comprehensive utilization of solid waste.Nickel slag and fly ash based polymer was prepared by activation of sodium silicate and sodium hydroxide composite alkali solution.The effect of fly ash content on the mechanical properties,anti freezing properties and anti seawater erosion properties of geopolymer was discussed,and the changing rules were expounded by means of XRD,SEM and pore structure analysis.The results showed that:① the strength of geopolymer is improved by the introduction of fly ash.When the fly ash content is 10%,the mechanical properties are optimal,and the 7 and 28 d compressive strengths are 37.2 MPa and 42.5 MPa,respectively,which are increased by 21.97% and 17.40% compared with the blank group.② Proper incorporation of fly ash can further reduce the compressive strength loss and mass loss of geopolymer in freeze thaw cycle and dry wet cycle.When 10% fly ash is added,the compressive strength loss rate and mass loss rate of the sample after 50 freeze thaw cycles are 24.7% and 14.9%,respectively,and the compressive strength loss rate after 50 wet dry cycles is 21.5%.③ Fly ash is beneficial to alkali excited reaction and increases reaction products.At the same time,the smaller particle size of fly ash provides a better filling effect on geopolymer.The results can provide reference for the development of nickel slag fly ash base polymer and the exploration of related durability problems.