One of the most common issues with highway construction is mud sticking to vehicle tires and being tracked onto public roads (herein referred to as “trackout”). This can result in dangerous, slippery conditions on roads travelled by the public, and in addition drivers are not happy about the prospect of mud being flung onto their vehicles. By many accounts, trackout accounts for the majority of complaints and violations for construction companies. To prevent trackout, the conventional approach is to install a rock driveway at the site exit. This is intended to provide sufficient roughness to dislodge attached mud prior to the vehicle exiting onto a public road. There are a number of manufacturers of devices which work on the same principle – to vibrate the tire sufficiently to dislodge the mud. However, there has been virtually no testing of any system for preventing mud trackout, nor any information on where trackout is most likely. This project is intended to determine the force necessary to dislodge mud from tires, with an evaluation of the effects of soil particle size distribution and moisture conditions. In addition, testing of the rock driveway and at least two additional commercial systems will be conducted at full scale. The results should provide guidance on the best mud removal approaches and systems and conditions where these are most likely needed.
Diamond grinding slurry (DGS) is a byproduct created by concrete pavement maintenance operations. Disposal of DGS is currently regulated based on minimal information. Currently, the NCDOT can land apply the material as a soil amendment, dispose of the material at a commercial facility, or use a mechanical press plate system to separate the water from the solids in order to reuse the water. Land application is possible, but the land required to safely apply the material is not always available. The other two methods are expensive as several million gallons for DGS are produced each year in North Carolina. Sediment basins used in sediment and erosion control have been effective at removing sediment from runoff. The proposed project is designed to determine if the same settling technology can be applied to DGS material to separate concrete residues from water in a cost effective basin. The water can then be reused in diamond grinding operations. Flocculating agents, such as polyacrylamide (PAM), will also be tested to see if they enhance separation of concrete particles. The results should provide improved guidance on DGS processing as well as the feasibility of a sediment basin compared to current disposal methods.
