Abstract: To promote the reuse of the waste rock debris, two typical claystone (A and B samples are collected from Tianshui, Gansu Province, and Changsha, Hunan Province respectively) are solidified by using cement as the modification and consolidation agent. The unconfined compressive strength, expansion deformation, and slake ratio are used as indexes, and the effects of solidification are evaluated. Then, modified sample’s mechanism was analyzed by scanning electron microscope (SEM) and nuclear magnetic resonance (NMR). The results show that cement modified and consolidation pretreatment could increase the strength and durability of claystone debris. However, the increase ratio of unconfined compress strength (UCS) is lower in the debris with high clay mineral content. When the mass fraction of cement is 7% and cured for 7 days, the UCS of A solidified body increases by 155%, and the UCS of B (whose claystone content is lower than A) solidified body increases more than 5 times. The Solidified A and B samples no longer completely disintegrate in water, and the 3h slake ratio decreased to 18.3% and 13.4%. Compared with only consolidation claystone debris, the porosity and pore size of the solidified debris are smaller. After the cement modification and consolidation, a large number of clay minerals are transformed from flocculent accumulation into massive polymers, which effectively improves the engineering properties of mudstone debris.

Key words: Cement Modification, Solidification, Unconfined Compressive Strength, Durability, NMR