About the research
Diamond grinding of portland cement concrete (PCC) highway surfaces, a maintenance operation carried out to extend the pavement service life, generates a high-pH and high alkalinity slurry (water, concrete, and aggregate residue), referred to as concrete grinding residue (CGR). The long-term impact of CGR slurry on soil properties (pH and infiltration) and vegetation needs to be investigated.
There is a potential for a number of ongoing/forthcoming Minnesota Department of Transportation (MnDOT) construction projects to place CGR slurries along Minnesota roadsides with potential environmental and economic implications. For instance, disposal of slurry along the “sensitive” areas of Marcoux corner (near Crookston, MN) can not only lead to reduced density of vegetation resulting in erosion problems, but can also increase the chance of invasion by exotic plant species that prefer open, well-drained soils, all of which have the potential to increase maintenance costs.
A better understanding of the potential soil chemistry impacts resulting from the application of CGR slurry may indicate preemptive soil amendments. Some previous studies have focused on investigating the influence of CGR slurry on soil pH and soil water infiltration rates in lab settings.
The objective of the proposed research is to gain a stronger understanding of the CGR effects on soil, water infiltration, and vegetation through an in-situ, statistically rigorous study that will analyze inslope and/or backslope soil samples and assess soil and vegetation properties before and after placement of the CGR.