纳米颗粒对粉煤灰水泥基材料干缩变形的影响及机理

发布时间：2018-04-16 22:38

本文选题：纳米颗粒 + 粉煤灰　；参考：《硅酸盐通报》2017年07期

【摘要】：为探讨纳米颗粒对掺粉煤灰的水泥基材料干缩变形的影响,选取了纳米SiO_2和纳米SiC两种纳米颗粒,分别制备了纳米改性粉煤灰水泥砂浆和混凝土试件,通过试验研究了纳米颗粒掺量对不同龄期粉煤灰水泥砂浆和混凝土干缩性能的影响,并分析了其作用机理。结果表明,掺纳米颗粒的水泥砂浆干缩率明显增大,掺量为2%的纳米SiO_2水泥砂浆和纳米SiC水泥砂浆的28 d干缩率较普通水泥砂浆分别增大了90%和120%;掺量为2%的纳米SiO_2混凝土和纳米SiC混凝土28 d干缩率较基准混凝土增大了124.8%和85.8%;纳米颗粒对粉煤灰水泥砂浆和粉煤灰混凝土干缩性能的影响很明显,而混掺与单掺纳米颗粒对混凝土的干缩率影响不大。分析认为,纳米颗粒比表面积大,吸附水分增多,造成内部自由水被大量消耗,同时由于纳米颗粒填充了混凝土内部结构中的微小孔隙,使得外部水分难以进入内部而被蒸发,造成内外变形不一致,最终增大了混凝土的干缩率。
[Abstract]:In order to investigate the effect of nano-particles on dry shrinkage deformation of cement-based materials with fly ash, two kinds of nano-particles, nanometer SiO_2 and nanometer SiC, were selected to prepare nano-modified fly ash cement mortar and concrete specimen, respectively.The effect of nano-particle content on the dry shrinkage properties of fly ash cement mortar and concrete at different ages was studied and its mechanism was analyzed.The results show that the dry shrinkage rate of cement mortar with nano-particles increases obviously.The dry shrinkage of nanometer SiO_2 cement mortar and nano SiC cement mortar with 2% content increased by 90% and 120% respectively compared with ordinary cement mortar, and the dry shrinkage rate of nano-sized SiO_2 concrete and nano- concrete with 2% content was higher than that of reference concrete in 28 days, respectively.The effects of nano-particles on the dry shrinkage properties of fly ash cement mortar and fly ash concrete are obvious.However, the dry shrinkage rate of concrete is not affected by mixing and single nano-particles.It is concluded that because of the large specific surface area of nanoparticles and the increase of adsorbed water, the internal free water is consumed a lot, and because the nanoparticles fill the tiny pores in the internal structure of concrete, the external water is evaporated because it is difficult to enter the inner structure.The internal and external deformation is inconsistent, and the shrinkage rate of concrete is increased.
【作者单位】：山西省交通科学研究院黄土地区公路建设与养护技术交通行业重点实验室;长沙理工大学交通运输工程学院;
【基金】：湖南省交通厅科技计划项目(201313) 黄土地区公路建设与养护技术交通行业重点实验室和山西省重点实验室开放课题(KLTLR-Y14-12) 长沙市科技计划项目(kh1601182)
【分类号】：TU528

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