A Comprehensive Investigation of New Coal Char-Based Cement Grouts: Impact of Curing Temperature, Environment, and Duration

Coal char-cement grout has emerged as an alternative material that counters the limitations of traditional cement grout. Recent studies underscore its efficacy in enhancing cement grout properties across diverse temperatures. However, there are no relevant studies comprehensively investigating the effects of curing temperature and environmental conditions on the properties of coal char-cement grout. This research systematically assesses coal char-cement grout performance, considering a spectrum of curing temperatures (5 °C, room temperature, and 35 °C) and environmental conditions (sealed, soaked, and mud). The evaluation centers on comprehensive macroscopic and material characterization tests. A declining trend in bulk density is evident, primarily attributed to increased porosity resulting from char addition. Nevertheless, minimal bulk density variations (1–3%) persist in the grouts, irrespective of curing conditions and duration. The microstructural analysis highlights the prevalence of empty pores in char particles, contributing to a reduction in the strength of coal char-grout samples across all curing conditions. This study sheds light on the intricate interplay between coal char-cement grouts, curing parameters, and resulting material characteristics, offering valuable insights for improving construction practices.