Effect of activated silica on polymerization mechanism and strength development of MSWI bottom ash alkali-activated mortars

• DOI: 10.1016/j.conbuildmat.2018.12.125
• Publication Date: 2019-01-02T18:36:35Z
• Authors: Guodong Huang; Yongsheng Ji; Jun Li; Linglei Zhang; Xiangyu Liu; Benlin Liu
• Keywords: Sodium polyacrylate

Abstract This study investigated the effect of activated silica on both the polymerization mechanism and strength development of municipal solid waste incineration (MSWI) bottom ash alkali-activated mortars, with a specific focus on increasing the silica content by adding either solid or liquid sodium silicate. The results show that such additives increase the content of active silicon and improve the resulting compressive strength of mortars, which is more effectively enhanced by liquid solid sodium silicate addition. However, a significant decline of these effects was found with increased addition of sodium silicate. Solid sodium silicate is difficult to dissolve; therefore, increasing its content not only fails to improve the content of active silicon but also causes precipitation. Using liquid sodium silicate could further improve the content of active silicon; however, excessive addition will result in a large surplus of activated silicon and thus, causing sodium and magadiite precipitation.