Winter litter
.jpg)
Winter litter , grit or litter is a generic term for various substrates that are used in the temperate , subarctic and arctic zones during the cold season ( winter ) to make snow-covered and, above all, icy paths and roads more grippy.
Thawing grit
In temperate climates , road salt and sodium chloride denatured with minor minerals are used to thaw snow and ice. The addition of salt lowers the freezing point of the water . For example, seawater with a salt concentration of 3.5% has a freezing point of −1.9 ° C, a saturated saline solution (356 g sodium chloride per liter of water) has a freezing point of −21 ° C. In practice, the icing of roads can at best be removed down to around −10 ° C with normal sodium chloride road salt. On the other hand, there are environmental problems caused by the salt , which is why its use is prohibited in most communities.
Dulling grit
So-called “deadening agents” are used primarily on roads with less traffic, as well as on cycle paths and footpaths. These dull the smoothness and do not melt the ice, but take away the slip when scattered.
- Grit
- Ordinary sand , such as that obtained from gravel pits and sandy beaches, can also be used. After the icing has thawed, it can be swept up and disposed of. Sand is less weather-resistant than granulates and is therefore used less often.
- Mineral granules
- Various gravel, gravel substrates , grit (litter) or expanded clay and the like can also be used. Their advantage is that they are not covered so quickly by fresh snow due to the size of the individual grains or stones. Due to the grain size, they are not pushed into the ice sheet as quickly as sand. After winter, these granules are collected in the course of street cleaning and used for road construction. However, some products are sharp-edged and hard, so that tiles or stoneware can be damaged if carried into the house under your shoes. Crumbly products that crush when stepping on are preferred here.
- Granules from renewable raw materials
- Granules made from harvest residues (e.g. corncob granules ) have a deadening effect against slippery winter conditions in ice or snow. Problems caused by salt, grit or ash on plant roots, shoes, building fabric, metal, flooring, groundwater or dog paws can be avoided. Organic grit does not generate dust and is heavy enough in wind. They can be scattered sparingly by hand or with a spreader bar. Scattered organic granulate remains weather-resistant, abrasion-resistant, dust-free and does not scratch sensitive surfaces in the house. However, they are more expensive than conventional means, but this is offset by handling advantages. Areas of application are above all sidewalks (pedestrian zones, footpaths in front of hotels, shops, authorities, hospitals and schools), road crossings. After use, the granulate can be safely swept into the green.
- ash
- used to be spread mainly in areas where a lot of wood or coal was used for heating. Today's stoves hardly produce any ash (100 kilograms of wood produce two to three kilograms of ash); it contains practically no unburned residues. Such residues (which can act as dulling particles on snow and ice) are only found in ashes from open chimneys . The water-soluble parts of the ash (raw potash ) have a similar effect to de-icing salt that lowers the freezing point on snow and ice.