纳米SiO2掺量对大掺量粉煤灰砂浆力学及收缩性能影响研究

粉煤灰是混凝土重要的辅助胶凝材料,在混凝土中应用广泛。然而,为避免对混凝土抗压强度产生较大影响,粉煤灰掺量一直较低。为促进粉煤灰在混凝土,特别是(超)高性能混凝土中的应用,研究了不同纳米SiO2掺量对大掺量粉煤灰砂浆(HFAM)力学及收缩性能的影响。研究结果表明,纳米SiO2可显著地提高HFAM抗压强度,掺量越大,则提高幅度越高。然而,在显著地增强HFAM抗压强度的同时,纳米SiO2也大幅提高了其自收缩,改变了自收缩发展规律,并引发了较大干缩变形。

Effect of nano-sized silicon powder on the strength and shrinkage properties of high volume fly ash mortar

Fly ash is one of the most important supplementary cementious material for concrete applied widely.However,the amount added of fly ash in concrete is limited since it can lead to significant reduction of the compressive strength of fly ash contained concrete.To promote the application of fly ash in concrete,especially in ultra high performance concrete,it tried to study the effect of nano-sized silicon powder on the strength and shrinkage properties of high volume fly ash concrete(HFAM).It found that nano-sized silicon powder can greatly improve the compressive strength of HFAM,the more the nano-sized silicon powder,the higher the compressive strength.However,the addition of nano-sized silicon powder into HFAM cause significant increase of the autogenous shrinkage as well as the drying shrinkage.Beyond that,the development of autogenous shrinkage was also altered.