纳米黏土对大掺量粉煤灰砂浆性能的影响

EFFECTS OF NANO-CLAY ON THE PROPERTIES OF MORTAR WITH HIGH-VOLUME FLY ASH

针对大掺量粉煤灰胶凝体系早期强度较低的缺点,研究了纳米黏土掺量(0. 6%~1. 0%)、水胶比(0. 4、0. 45和0. 5)及粉煤灰掺量(50%~70%)对大掺量粉煤灰胶凝体系的流动度、抗压强度及抗折强度的影响规律。结果表明:粉煤灰胶凝体系的粉煤灰量越多,体系的流动性越高,抗压强度和抗折强度越低;纳米黏土的掺入导致大掺量粉煤灰胶凝体系的流动度降低,且掺量越大,流动度越低,下降幅度在13. 0%~29. 6%;纳米黏土的掺入可以明显提高大掺量粉煤灰胶凝体系的28 d抗压强度,提升幅度在37. 5%~49. 5%,且对于60%粉煤灰掺量的体系来说,最佳纳米黏土掺量为0. 6%;纳米黏土也提高了大掺量粉煤灰胶凝体系的抗折强度,提升幅度在15%~20%。

In the paper,nano-clay(NC) was used to modify the properties of cementitious system with high-volume fly ash(FA) to overcome the disadvantage of low strength. The effects of NC content(0. 6% ~ 1. 0%),waterbinder ratio(0. 4,0. 45,0. 5),and fly ash(FA) content(50% ~ 70%) on the fluidity,compressive strength and flexural strength of the cementitious system with high-volume fly ash were studied. The results showed that the more content of FA,the higher fluidity of the system,and the lower compressive strength and flexural strength. The incorporation of NC resulted in a decrease in the fluidity of the FA cementitious system,and the more content of NC,the lower the fluidity with the decreasing range between 13. 0% and 29. 6%. NC could significantly improve the compressive strength of high-volume FA cementitious system within 28 days,which was between 37. 5% and 49. 5%.For the high-volume FA cementitious system with 60% FA,the highest compressive strength was obtained with 0. 6%NC. Meanwhile,the NC increased the flexural strength of the FA cementitious system by between 15% and 20%.