Novel coal char-based cement grout: An experimental study on geotechnical and rheological properties

Abstract

Coal char, a light and porous coal byproduct, is conventionally used for combustion and gasification, which leads to high carbon dioxide and other air pollutants emissions. In this study, the feasibility of using coal char in cement grout is evaluated. The coal char pyrolyzed at 850 °C is produced from Powder River Basin coal in Wyoming. Effects of char contents (up to 50%) and particle sizes (<300 μm and 300–850 μm) on geotechnical and rheological properties of char-cement grouts are comprehensively investigated. Compared to cement grout, the compressive strength of char-cement grout is 16% higher, and the final setting time is 55% shorter. The addition of coal char effectively reduces the bleeding in grouts without leading to a significant increase in Marsh viscosity. In general, coal char can provide many advantages towards improving engineering performance and broadening application of conventional cement grout.