纳米改性WBP-CFA地聚合物的耐久性和孔结构

Durability and Pore Structure of Nano-particle-modified Geopolymers of Waste Brick Powder-class C Fly Ash

使用废弃粘土砖粉(WBP)和高钙粉煤灰(CFA)制备复合地聚合物,用纳米颗粒对其进行改性,研究了纳米改性WBP-CFA地聚合物的抗冻性和抗渗性及其与孔结构之间的内在关联。结果表明,单掺纳米SiO_2的改性效果优于纳米Al_2O_3,复掺2%(质量分数,下同)纳米SiO_2和1%纳米Al_2O_3的地聚合物试样的抗渗性和抗冻性优良。冻融使地聚合物的体积密度降低,显气孔率和真气孔率提高;平均孔径和最可几孔径均增大,孔隙率提高;小于50 nm的无害孔和少害孔减少,大于50 nm的有害孔和多害孔均增加。

Nano particle modified composite geopolymers were prepared with waste brick powder （WBP） and class C fly ash （CFA） as raw material, and nano-particales SiO2 and Al2O3 as modifier. Then their anti-permeability and anti-freezing-thawing as well as their pore structure were investigated. Results show that nano-SiO2 is superior to nano-Al2O3 for enhancing the performance of geopolymers, and the combination of 2%（mass fraction） nano-SiO2 and 1% nano-Al2O3 exhibits the best modification effect, so that the geopolymer possesses the highest anti-permeability and anti-freezing-thawing. It is found for the geopolymers after being freezing-thawing tested that the apparent porosity, true porosity, average pore size, the size of the most probable pores and the total porosity all enhanced, however the volume density decreased. Besides, the harmless and less-harmful holes with size smaller than 50 nm decreased, and in the contrast, the harmful and more-harmful holes increased.