Study of Engineering Behavior of Coal Mine Waste Generated From Barapukuria Coal Mine As Road Subgrade

This study is focused on the possibility of using coal mine wastes as a replacement for conventional road subgrades. Various laboratory tests carried out on fresh coal mine waste collected from Barapukuria Coal Mine (Located at Dinajpur, Bangladesh) showed that, it behaves like low strength soil with 0.71% CBR and 18.74% plasticity index which is unsuitable for engineering utilization. Later, fine sand and cement were added with the waste. Three different cement proportion were tested (5%, 8% and 10% of total weight) keeping a constant sand proportion (20% of total weight). The unconfined compression strength and CBR value were found to increase greatly. Analyzing the test results, waste mixed with 8% cement and 20% sand showing 27.44% CBR and 9.09% plasticity index was found to be effective for using as subgrade. Chemical analysis of waste detected the presence of lead as 0.026 ppm which may cause groundwater contamination.