Influence of Freeze-Thaw Cycles on Strength and Heavy Metal Leaching Performance of Petroleum Drilling Mud Stabilized by Waste-Paper

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The study evaluated whether industrial by-products can stabilize petroleum drilling mud containing heavy metals and improve its resistance to freeze–thaw damage. Samples were treated with Portland cement alone or mixtures containing blast-furnace slag, fly ash, phosphogypsum, lime, and aluminum sulfate. Researchers measured unconfined compressive strength after up to eight freeze–thaw cycles, Pb and Cr leaching, and pore structure.<br /><br />Strength declined with increasing freeze–thaw cycles for all mixtures. However, replacing more cement with industrial by-products—particularly phosphogypsum—reduced strength loss. The mixture containing the highest proportion of industrial residues, with no cement, showed the best freeze–thaw resistance among the tested formulations.<br /><br />Industrial-residue mixtures also limited heavy-metal leaching more effectively than cement alone. After four or eight cycles, the cement-free formulation released approximately 70% less lead and 76–83% less chromium than the cement-only samples. Mercury intrusion tests showed that industrial-residue-stabilized soil was denser, with lower pore volume, than cement-stabilized soil. Freeze–thaw cycling increased pore volume, corresponding to reduced strength and increased leaching.<br /><br />The authors conclude that industrial by-products can improve the durability and contaminant-retention performance of stabilized drilling mud, supporting its potential use as road material in cold regions.

Keywords

industrial by-products

petroleum drilling mud

heavy metals

freeze-thaw resistance

Portland cement

blast-furnace slag

fly ash

phosphogypsum

leaching

compressive strength