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Assessment and Mitigation of Potential Environmental Impacts of Portland Cement Concrete Highway Grindings

Description: The primary objectives of this study were to quantify the affect of PCC slurry on roadside soil pH and to evaluate the effectiveness of using compost to at least partially neutralize slurry pH. Soil pH as a function of depth was determined along known areas of slurry disposal (I-90 and SR-195). Soil metal concentrations (cadmium, copper, lead and zinc) and soil calcium concentrations were also determined. Slurry pH neutralization tests were performed by blending compost (from two different sources) with PCC grinding slurry at three slurry:compost ratios and monitoring pH as a function of time. Roadside soil pH was shown to be significantly elevated in some areas along SR-195 and slightly elevated in some of the I-90 sampling locations. Compost was shown to reduce slurry pH from about 12 to as low as 8.6 for a slurry:compost ratio of 5:1 (w/w). No significant difference between background soil metal concentrations and those in impacted areas was observed.

  • Date Published: August, 2005
  • Publication Number: WA-RD 628.1
  • Last Modified: April 5, 2007
  • Authors: David Yonge, Harini Shanmugan.
  • Originator: Washington State Transportation Center (TRAC)
  • # of Pages: 43 p., 457 KB (PDF)
  • Subject: Cadmium, Calcium, Compost, Concentration (Chemistry), Concrete pavements, Copper, Depth, Environmental impacts, Grinding, Highway maintenance, Lead (Metal), Metals, Neutralization, Pavement maintenance, pH value, Portland cement concrete, Resurfacing, Roadside, Slurry, Soils, Surface course (Pavements), Zinc.
  • Keywords: I-90, SR 195, Portland cement concrete, highway resurfacing, diamond grinding, PCC, PCC slurry disposal.
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This abstract was last modified January 26, 2009