超细粉煤灰特性及其在混凝土中的应用研究

Study on characteristics of ultrafine fly ash and its application in concrete

制备了不同细度(674、810、1126 m2/kg)的超细粉煤灰,研究了其掺量(0~25%)对水泥-超细粉煤灰胶凝材料性能的影响,分析了掺不同细度超细粉煤灰混凝土的工作性、力学性能和耐久性能。结果表明:超细粉煤灰的强度活性指数和需水量比均随着其细度的增加而增大;用0~25%的超细粉煤灰替代P·O 42.5级水泥后,胶凝材料的初凝、终凝时间分别延长了11~71 min、13~74 min;与未掺超细粉煤灰的混凝土相比,掺超细粉煤灰混凝土的坍落度提高,3 d和7 d抗压强度相差不大,28、56、90 d抗压强度均有所提高,抗碳化性能和抗硫酸盐侵蚀性能均有所提升。

Ultrafine fly ash with different fineness(674,810,1126 m2/kg)was prepared,and the effects of its content(0~25%)on the properties of cement-ultrafine fly ash cementitious materials was studied.The workability,mechanical properties,and durability of concrete with different fineness ultrafine fly ash were analyzed.The results show that the strength activity index and water demand ratio of ultrafine fly ash increase with the increase of the fineness.After replacing P·O 42.5 cement with 0~25%content of ultrafine fly ash,the initial setting time and final setting time of the cementitious materials are extended by 11~71 min and 13~74 min,respectively.Compared with the concrete without ultrafine fly ash,the slump of concrete with ultrafine fly ash is increased,the 3 d and 28 d compressive strength are not significantly different,the 28 d,56 d,and 90 d compressive strength are increased,and the carbonation resistance and sulfate corrosion resistance are improved.