激发剂对风积沙微粉强度的影响

Effect of Activator on Strength of Aeolian Sand Powder

为了更好地将风积沙用作辅助胶凝材料,采用激发剂与风积沙一体化磨粉的方式,对风积沙进行活化试验。试验结果表明:风积沙微粉等质量替代30%水泥时,碱类与醇胺类激发剂对风积沙微粉的活化效果好于硫酸盐类激发剂;通过正交试验确定的复合激发剂能显著提高风积沙微粉胶砂的后期抗压强度,7 d抗压强度比提高了11%,28 d提高了13%;对风积沙微粉28 d的水化产物进行SEM试验,发现掺复合激发剂风积沙微粉胶砂试件生成物中存在丰富的纤维团簇状C-S-H凝胶与细长柱状AFt晶体相互交织,形成空间网状结构,填充在孔隙中,使胶砂试件结构致密。研究成果可为以后风积沙微粉的工程应用提供技术理论依据。

To better use aeolian sand as auxiliary cementitious material,we prepared specimens by grinding aeolian sand together with different activators respectively to test the compressive strength of cemented aeolian sand powder.Results demonstrated that the activation effect of alkali and alcohol-amine activators on aeolian sand powder is better than that of sulfate activator when 30%cement is replaced by aeolian sand powder in an identical proportion.Composite activator determined by orthogonal test could enhance the 7 d compressive strength ratio of the cemented sand specimen by 11%and the 28 d ratio by 13%.Furthermore,we found abundant interlaced fiber cluster C-S-H gel and slender columnar AFt crystal from the SEM images of the 28 d hydration products of aeolian sand powder.A spatial reticular structure is formed and pores are filled,which compacts the structure of the cemented sand specimen.