Thesis
Assessment and mitigation of potential environmental impacts of Portland Cement Concrete highway grindings
Master of Science (MS), Washington State University
2004
Handle:
https://hdl.handle.net/2376/276
Abstract
Diamond Grinding of Portland Cement Concrete (PCC) pavements to improve smoothness and remove surface irregularities often caused by faulting, curling, and warping of the slabs is a highway rehabilitation technique. The grinding slurry generated during the grinding operation is typically deposited along the roadside and concern has been expressed regarding potential for negative environmental impacts. The greatest potential for negative environmental impact was believed to be the slurry pH as the Washington State Department of Transportation has documented that PCC slurry has elevated pH levels. This study was commissioned by Washington State Department of Transportation to define the impact of PCC highway grinding slurry on soil pH in disposal areas and evaluates the use of compost to neutralize slurry pH prior to or during disposal. The results indicate that soil pH was found to be higher in slurry disposal areas in comparison with the non-impacted areas. The pH of the soil in the slurry disposal area on SR-195 ranged from 7.6-9.4 while background pH ranged from 6.3-7.5. Soil pH within the slurry disposal area on I-90 was in the range 7.1-8.2, indicating a moderate increase above the range of pH 7.1-7.2 for background samples. This indicates that slurry application does increase soil pH in the disposal areas. Compost was shown to neutralize the slurry pH, based on the pH neutralization experiments. The observed pH reduction ranged from about 3.5- 4.5 units below the slurry pH of 12. The minimum observed pH was 8.3 with WSU compost and 8.0 for EKO compost for slurry: compost ratio of 1.3 gallons slurry: 2.2pounds compost. EKO compost had a greater effect on pH reduction than did WSU compost.
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Details
- Title
- Assessment and mitigation of potential environmental impacts of Portland Cement Concrete highway grindings
- Creators
- Harini Shanmugam
- Contributors
- David Yonge (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Civil and Environmental Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Identifiers
- 99900525079001842
- Language
- English
- Resource Type
- Thesis