超细活性粉煤灰对碱激发矿渣体系的影响研究

Study on the Effect of Reactive Ultra-fine Fly Ash on Alkali-activated Slag System

以磨细高炉矿渣(G)与超细活性粉煤灰(RUFA)为原料,采用氢氧化钠作为碱性活化剂,制备了矿渣-超细活性粉煤灰地质聚合物,对其流动性及力学性能进行研究,并分析其化合产物。结果表明:外掺8 mol/L的氢氧化钠作为碱激发剂、液固比为0.35时,随着超细活性粉煤灰掺量的增加,浆料的流动度呈现先上升后下降的趋势;在超细活性粉煤灰掺量不大于50%情况下,掺量越大,试件的抗压强度呈现逐渐增加的趋势;超细活性粉煤灰掺量为50%时,7 d抗压强度达到了67.8 MPa, 28 d抗压强度达到了85.9 MPa;XRD与SEM分析表明,随着超细活性粉煤灰掺量的增加,地聚合反应越来越充分,生成更多的硅铝酸盐凝胶状产物,并且原料中部分晶相逐渐转化为非晶相,未反应超细活性粉煤灰颗粒可以填充孔隙,使试件的结构变得致密,有利于试件抗压强度的提高。

Using pulverized blast furnace slag(G) and ultra-fine active fly ash(RUFA) as raw materials, and using sodium hydroxide as alkaline activator, the slag-ultra-fine active fly ash geopolymer was prepared.The results show that when NaOH is mixed with 8 mol/L as alkali activator and the liquid-solid ratio is 0.35,the fluidity of slurry increases firstly and then decreases with the increase of RUFA content.When the content of RUFA is less than 50%,the compressive strength of the specimen increases gradually with the increase of the content of RUFA.When the content of RUFA is 50%,the compressive strength of the specimen reaches 67.8 MPa at 7 days and 85.9 MPa at 28 days.XRD and SEM analysis show that, with the increase of RUFA content, the geopolymerization reaction becomes more and more full, and more silicoaluminate gel products are generated, and part of the crystalline phase in the raw material is gradually transformed into amorphous phase.The unreacted RUFA particles can fill the pores, densify the structure of the specimen, which is conducive to the improvement of the compressive strength of the specimen.