Strength and Durability of Cement Based CLSM Developed using Iron Mine Overburden

The dumping of mining waste occupies extensive areas of land and poses environmental hazards, including heavy metal leaching, dust pollution, and slope failure. Iron mine overburden (MO), a byproduct of iron mining, exacerbates these issues when dumped. To address the challenges of storing MO, it was combined with fly ash and cement to develop controlled low-strength material (CLSM). Initially, the raw materials were examined for their physical, chemical, and mineralogical properties. Subsequently, ۲۴ different CLSM mixtures were prepared by varying cement, fly ash, MO, and water-to-binder ratios. The fresh mixes were tested for flowability, bleeding, and fresh density, while the hardened properties, including density, unconfined compressive strength (UCS), and durability, were also evaluated. Results showed that all CLSM mixes were highly flowable, with flow diameters exceeding ۱۵۰ mm, and some exhibited self-leveling behavior. The ۲۸-day compressive strength ranged from ۰.۵۲ MPa to ۴.۲۸ MPa, with a few mixes being soft enough for manual excavation. Durability tests indicated that approximately ۶۰% of the mass remained intact after eight wet-dry cycles, demonstrating good resistance to erosion. This study highlights the potential for utilizing mining waste in sustainable construction materials.

کلیدواژه ها:

Flowability ، Bleeding ، Strength ، durability