During winter, one of the main activity in High Altitude Area is snow clearance.
Snow clearance is the job of removing snow from road surface to make travel easier & safer. It can be done manually & mechanically.
Manually:-
For very light snow, brooms can be used to brush off the snow.
For considerable amount of snow, Hand tools like spade and shovels are used.
Removing icing is more difficult ,even pick axes may be required sometime.
Mechanically:-
Dozer & wheel loader/Back Hoe loader are usually used to clear snow.
One of main Problem during winter is Icing. De-icing activity is removal of ice layer formed during winter/snowfall.
It
can be scrapped off mechanically or using chemical /inert material.
Chemicals
are used before or during the onset of snowfall in order to prevent formation
of ice or adhesion of ice to road surface.
Most
commonly used chemical is Sodium chloride (common salt). It is inexpensive and
readily available. Brine(salt in water) lowers the freezing point of water to – 18o C &
causes snow/ ice to melt at lower temp.
However, salt has tendency to cause corrosion.
Compound
like Urea (commonly used fertilizers) reduce environmental effect & have longer
residual effect. These are effective for area with temperature up to – 20o C. It is good for vegetation but over use of Urea may cause
damages to vegetation.
For very colder places like temp < – 20o C, CaCl2 may be used. It lowers freezing temp & also produce exothermic reaction . It is five times more expensive than NaCl.
Inert material (like sand,girt) are also used on road surface . They don’t melt snow but they improve traction. With melting of snow, traction also reduces. These can be mixed with chemicals to minimize the use of chemical. De-icing chemical and inert material need to be selected/ applied carefully. Sand can clog pavement joint in rigid pavement.
Snow poles are installed on roads to identified the edge/ perimeters of road.
During this time, vehicle and machine will require non skid chain to perform their task.
Main artery roads, Roads with steep slope or other dangers shall be given priority during snow clearance.
