Diamond Grinding Slurry

Diamond grinding of highway surfaces is a one-time maintenance operation to extend the highway surface life. Concrete grinding residue (CGR) is the byproduct of diamond grinding and has high pH, calcium, potassium, magnesium, and sodium concentrations and small particle size. Disposal of CGR in Nebraska in 2012 changed from unregulated roadside discharge to a National Pollutant Discharge Elimination System (NPDES) permit. The NPDES permit restricted the amount of CGR that can be roadside applied to 5 tons/acre or the agronomic liming rate whichever is lower. Agronomic liming rate is intended for liming applications to acidic agricultural fields where a minimum amount of liming material is added in a cost effective way to reach a specific target pH, commonly 6.5. However, the Nebraska Department of Roads (NDOR) cannot routinely justify an agronomic liming rate as high as 5 tons/acre to roadside soils because pH of roadside soils may not always be acidic. In addition, CGR slurry typically having a pH of 11-12 may have negative effect if applied to existing vegetation as well as on soil physical conditions. Thus, NDOR needs information regarding the application rates of CGR to roadsides, that will maximize weight applied to a given area, thus minimizing transportation costs, without causing detrimental impacts to soils properties (chemical and physical) or roadside vegetation. Previous greenhouse studies where 37 and 116 tons/acre equivalent CGR was applied to roadside soil indicated that the addition of an equivalent 37 tons/acre of CGR increased soil pH from 8.0 to 8.6 on fine sandy loam and from 7.9 to 8.3 on silty clay (DeSutter et al. 2011a). In the same greenhouse study, shoot biomass of smooth bromegrass (Bromus inermis L.) was measured 80 days after seeding in the treated pots. Application of 37 tons/acre either increased (fine sandy loam) or did not change (silty clay) shoot biomass compared to the untreated control. Laboratory studies where a 2.5mm depth surface layer (6.5 kg/m2 -[29 tons/acre]) of CGR was applied to the same soils resulted in a significant increase in water infiltration in the silty clay loam but not in the fine sandy loam (DeSutter et al 2011b). The improved infiltration may likely be due to improved aggregation of the soil particles by the CGR high calcium content. No reports in the literature have been identified that evaluated short- and medium-term effects of CGR application to in-situ soil properties or existing roadside vegetation. Furthermore, no studies in this area have been conducted in Nebraska. Thus research to determine the effect of one-time application of different CGR rates to roadside soil properties and existing vegetation is needed.

    Language

    • English

    Project

    • Status: Active
    • Funding: $88972.00
    • Contract Numbers:

      SPR-P1(13) M335

    • Sponsor Organizations:

      Nebraska Department of Roads

      1500 Highway 2
      Lincoln, NE  United States  68502

      Federal Highway Administration

      Department of Pavement Technology, HIPT-10
      1200 New Jersey Avenue, SE
      Washington, DC    20590
    • Performing Organizations:

      University of Nebraska, Lincoln

      Lincoln, NE  United States 
    • Principal Investigators:

      Dennis, McCallister

    • Start Date: 20121001
    • Expected Completion Date: 0
    • Actual Completion Date: 20150831
    • Source Data: RiP Project 33188

    Subject/Index Terms

    Filing Info

    • Accession Number: 01569422
    • Record Type: Research project
    • Source Agency: Nebraska Department of Roads
    • Contract Numbers: SPR-P1(13) M335
    • Files: RiP, STATEDOT
    • Created Date: Jul 11 2015 1:00AM