Research Article
Utilization of Electroplating Sludge as Subgrade Backfill Materials: Mechanical and Environmental Risk Evaluation
Table 1
Physical characteristics and chemical composition of sludge, fly ash, and cement.
| | | Sludge | Coal fly ash | Portland cement |
| | Physical characteristics | | | | | Moisture (%) | 70 | 20 | 0.5 | | Density (g/cm3) | 1.05 | 2.9 | 3.18 | | pH | 4.8 | 10.36 | 13 | | Specific gravity (g/cm3) | 2.65 | 2.34 | 3.13 | | Specific surface area (cm2/g) | 3400 | 3413 | 3550 |
| | Chemical composition (%) | | | | | Cu | 23.17 | — | — | | Fe | 2.12 | 2.95 | 2.34 | | Al | 0.43 | 15.46 | 3.07 | | Ca | 25.29 | 3.53 | 47.0 | | Si | 0.4 | 25.24 | 9.4 | | S | 1.16 | 0.69 | 1.08 | | Zn | 2.53 | — | - | | Pb | 1.03 | — | - | | Mg | 0.40 | — | 0.50 | | Cr | 2.5 | — | — | | Mn | 1.62 | — | — | | Rh | 23.22 | — | — | | V | 12.93 | — | — | | Sr | 2.6 | — | — | | Ti | — | 0.40 | — | | Na | — | — | 3.19 | | K | — | — | 0.42 | | Cl | — | — | 0.005 |
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