Grikol is a new de-icing product which is developed by the Russian research and production–institute NPO Rosdornii in Moscow. Grikol is a filler to the asphalt-concrete and consist of 80% Sodium chloride (NaCl), 10% Calcium Chloride (CaCl2) and 10% Siakor.
The unique part of Grikol is the component Siakor which is a silicon–organic, non-toxic, non-flammable -compound in powder format with a freezing-point of -50 degrees Celsius. Siakor is an inhibitor against corrosion and can also be used as a water rejecting, “anti-corrosion” substance. Siakor adds extra de–icing effect to the chlorides and reduces the corrosion damage by binding the redundant chlorides from Grikol and form an insoluble compound of these.
Grikol is developed to prevent ice from forming on the road surface and is used as a filler when the asphalt-concrete is mixed. Grikol is used in the upper layer of the pavement according to traditional technology.
Grikol has a solid anti–icing effect in temperatures between 0 to -6 degrees Celsius and therefore prevents ice formations on the road when the temperature starts to fall. In lower temperatures (below -6) Grikol prevents ice and snow from freezing and to get stuck on the road surface, this makes the maintenance job much easier and less expensive.
According to NPO Rosdornii Grikol will compensate for all its initial costs even during its first year in use because of the reduced road maintenance, safer roads (less traffic accidents), less corrosion on vehicles and a cleaner environment.
Theoretical determination of salt emission – Grikol pavements
The following relations are used:
(number of vehicles) × (frequency of vehicles with studded tires) × (grams of eroded pavement per km, vehicles with studded tires) × (percentage of Grikol in pavement)
According to Kent Gustafsson at ”VTI” the approximate erosion of a vehicles with normal tires is about 1% compared to a vehicles with studded tires.
Calculation of salt-emission per 1000 YDT (yearly average daily traffic), square meters of lane and year: 2,43 × (1000 × 185 × 1,0 × 0,05 × 0,027) / (1000 × 3,5) = 2,50 gram
Calculation of salt-emission per 1000 YDT, square meters of lane and winter season: 1000 × 180 × 0,35 × 5 × 0,027 / (1000 × 3,5) = 2,43 gram (erosion from un-studded tires are negligible)
Calculation of salt-emission per 1000 YDT, kilometers of lane and winter season: 1000 × 180 × 0,35 × 5 × 0,027 = 8505 gram (erosion from un-studded tires are negligible)
Reflections on calculations of salt-emission
There are some uncertain
parameters in the calculations above, for example the erosion. However,
calculations gives us a clear indication of the magnitude of
It also becomes clear that the salt-emission is in direct proportion to the amount of vehicles, the frequency of vehicles with studded tires and the amount of Grikol used in the pavement.
The result of these
calculations shall be compared to the amount of regular road salt
used during the past years. According to information from Lennart Karlström
at ”Stockholm Entreprenad” the amount of salt used in Stockholm during
the winter season of 93-94 was
in average 507 gram per square meter.
If you count with an average of 10.000 YDT in Stockholm, you will get (according to the calculations above) 25 gram of salt per square meter and year when using Grikol pavements.
That is only one-twentieth of the usual slat-emission. Usually we claim that using Grikol will decrease the salt-emission to one-tenth of the usual. This calculation includes some complementary salting.
Another question that arises
is how far this relatively low amount of salt
which erodes from the Grikol
pavement will last in a matter of de-icing the road?
I believe that only active service measurements with a “friction-car” can give us reliable information in this matter. However, to get a rough estimation we have calculated on some reasonable and theoretical arguments below.
De-icing ability of a Grikol pavement - Theoretical calculations
Calculated amount of Grikol
which is exposed on the road surface but still bound to the
0,03 × 0,001 × 2.350 × 0,03 = 2,1g/m²
Reflections on theoretical calculations of de–icing ability
In the calculations above we assume that the exposed salt does not leach. This may be probable to some extent because the erosion makes the pavement constantly expose new salt particles and because of the Siakor in Grikol, which besides the freezing point-lowering properties, also has a moisture-resistant feature that counteracts the leaching.
The result of 2,1g/m² shall be compared to the information provided by Lennart Axelsson at VV (the highway department), that it takes 5-10g/m² when the road surface holds a water volume of 0,1mm (this gives a salt solution of 5-10%) to give the pavement a sufficient de-icing capacity. Other factors that affect the de-icing and friction: