Experimental evaluation of shrinkage properties in concrete incorporating coal mine waste rock

Abstract

This research investigates the properties of concrete utilizing coal mine waste rock (CMWR) as a substitute for river sand. The workability of fresh concrete is assessed through slump tests, revealing a decrease in a slump as the percentage of CMWR replacement increases. The density of the concrete mixtures increased with curing time, and the compressive strength also exhibited an upward trend but with lower values compared to the control concrete when CMWR was used as a replacement. The reduction in compressive strength ranges from 11.4% to 47.6% for CMWR replacement levels of 25% to 100%. The study also examines the influence of climate conditions, including temperature and humidity. Shrinkage deformation tests indicate that CMWR concrete demonstrates higher plastic and dry shrinkage than river sand concrete. CMWR concrete exhibits significantly higher drying shrinkage, attributed to the enhanced water absorption capacity of CMWR particles. These findings provide valuable insights into the performance of concrete incorporating CMWR and propose potential strategies for mitigating its effects. The research outcomes contribute to the knowledge base in the field and offer practical implications for the operation of CMWR in concrete applications