Coupled effects of superplasticizers and glazed hollow beads on the fluidy performance of cemented paste backfill containing alkali-activated slag and MSWI fly ash

Abstract

To acquire solid knowledge on the coupled effects of superplasticizers and glazed hollow beads (GHB) on the fluidity of backfill materials, the impact of municipal solid waste incineration (MSWI) fly ash content, superplasticizer type and content, GHB content and solid concentration were studied. Additionally, scanning electron microscopy-energy dispersive spectroscopy and methods for determining total organic carbon (TOC) were used to study the mechanism of action of superplasticizers. The TOC test results indicated that the adsorption between naphthalene sulfonate (NS) and MSWI fly ash was the weakest. After adding NS, the morphology of ettringite changed from slender acicular to short columnar. NS has the best effect on improving fluidity. Adding 0.5% NS and 6% GHB increased the solid concentration by 4%, and the compressive strength increased by 55%. The synergistic action of NS and GHB can significantly improve the fluidity, improve the engineering efficiency and reduce the backfill cost.