Effect of Concrete Grinding Residue on Roadside Soil Properties

During diamond grinding operations for smoothing concrete pavement surfaces, water is used to cool the diamond blades. This water, combined with cutting residue, generates a high pH and high alkaline slurry byproduct referred to as concrete grinding residue (CGR). Although spreading CGR along roadsides is one of the most commonly used disposal methods, it is always of concern because of its potential effect on roadside soil properties. A field study was therefore conducted in 2016 on two roadside slopes beside Highway I-90 in Minnesota on which CGR slurries were offloaded in 2009 and 2013, respectively. The chemical properties of soils that received this CGR were measured and compared with those of adjacent soils that had not received CGR. The areas after receiving CGR slurry exhibited that pH reduced by 0.78 while electrical conductivity (EC) and calcium concentration increased by 0.48 ds m^-1 and 97 mg kg^-1, respectively. Because spreading of CGR did not cause any perceptible reduction in soil quality, CGR was not deemed to be of long-term concern with respect to roadside environments.