Warm wetted sand is a method were the sanding material is mixed with hot water while spreading and were the sand adheres to a cold surface through a process of melting and freezing. Comparing measurements of friction clearly showed higher levels of friction improvements and with a longer duration when using warm wetted sand for skid control on walkways and bike paths compared to traditional dry sand. The method using warm wetted sand was most effective on sections with on-street-cycling were the road condition more often is thick ice. Since the equipment used for spreading warm wetted sand is rather large and heavy it is also more applicable for the use on these types of sections. According to the observations of the maintenance operators and to the maintenance protocols, the number of actions can be reduced when using warm wetted sand instead of traditional dry sand on walkways and bike paths. It is therefore possible to reduce the amount of grit spread when using the method, but there is additional fuel consumption for heating the water. Although the method using warm wetted sand results in higher levels of friction improvements at a longer duration than when using traditional dry sand, the results are not promising enough to motivate an investment in equipment for skid control on walkways and bike paths only. However, when the equipment is also used for skid control at bus stops, in roundabouts and crossings, as in the municipality of Umeå, it might as well be used on walkways and bike paths. A multi-purpose use is cost effective and motivates the investment to a larger extent. In this study, the applicability of using warm wetted sand on walkways and bike paths has been evaluated in Umeå municipality during the winters of 2010/11 and 2011/12. To evaluate benefits and drawbacks using the method on walkways and bike paths measurements of friction, road condition observation, maintenance protocols and interviews with maintenance operators, cyclists and pedestrians were performed and comparisons were made with traditional dry sand. (Author/publisher)
Samenvatting