Solidification/stabilization of used abrasive media for non-structural concrete using portland cement. Interim research report
Highway bridges in the United States are painted to resist corrosion and to help maintain the structural integrity of the bridge. Periodically, it is necessary to remove the existing paint so that the surface can be repainted. Most often the removal process consists of blasting the surface with an abrasive such as sand or slag. The blast media then contains elements present in the paint, such as cadmium, chromium and lead. The spent media may be a hazardous waste as defined by EPA`s Toxicity Characteristic (TC) criterion. This criterion uses the Toxicity Characteristic Leaching Procedure (TCLP) to determine whether a waste is classified as a hazardous waste. This procedure subjects the waste to a highly acidic environment in which chemicals can leach out of the waste. The leachate enviornment is then analyzed to determine the concentration of chemical leached, which must fall within the TC criterion. Some spent blasting material has been shown to have TCLP metal concentrations exceeding the TC criterion. The Texas Department of Transportation (TxDOT) has begun to recycle spent abrasive media in portland cement-based concrete using solidification/stabilization (S/S) techniques. This technology is designed to immobilize the metals while recycling the spent abrasive media as a component in non-structural concrete. The study has revealed the effectiveness of portland cement-based S/S systems in recycling contaminated spent abrasive media in portland cement-based concrete. The long-term leaching behavior of metals from these concrete products was examined using sequential extraction leaching tests.
- Research Organization:
- Texas Univ., Austin, TX (United States). Center for Transportation Research
- OSTI ID:
- 160938
- Report Number(s):
- PB--96-111125/XAB; CTR--0-1315-2
- Country of Publication:
- United States
- Language:
- English
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