粉煤灰活化及其胶凝性能研究

Study on Activation of Fly Ash and Its Cementitious Properties

通过热活化、复合活化和酸活化三种方法对粉煤灰进行活化处理,以期提高其潜在胶凝性能。结果表明:复合活化的粉煤灰活性效果最好,结合XRF、XRD和IR分析发现此方法有效地将粉煤灰中惰性组分二氧化硅和三氧化铝转变为无定形态,通过SEM发现粉煤灰表面形成了很多疏松的孔洞。将三种活化粉煤灰制备成胶凝试块,养护3,7,28 d测其抗压强度,复合活化粉煤灰制备的胶凝试块凝固周期明显缩短,在养护7 d的抗压强度性能就达到了GB/T 177(Ⅱ)要求。

Fly ash is an inorganic mineral powder after pulverized coal combustion in coal-fired power plants.It is one of the largest solid wastes in China.Fly ash used in concrete has good hardness,high temperature resistance and freeze-thaw performance.In order to improve its potential cementitious properties,fly ash was activated by thermal activation,compound activation and acid activation in this paper.The results showed that the compound activated fly ash had the best activity.Combined with XRF,XRD and IR analysis,it was found that this method can effectively convert the inert components of silica and alumina into amorphous form in fly ash.Many loose holes were found on the surface of fly ash by SEM.Preparation of three kinds of activated fly ash into cementitious test block and test its compressive strength after curing for 3,7 and 28 d.The solidification period of cementitious test blocks prepared by composite activated fly ash is obviously shortened.After curing for 7 d,the compressive strength performance reaches GB/T 177(Ⅱ)requirements.