|
It is always desirable to have an even surface, but it is seldom possible to
have such a one.
Even if a road is constructed with high quality pavers, it is possible to
develop unevenness due to pavement failures.
Unevenness affect the vehicle operating cost, speed, riding comfort, safety,
fuel consumption and wear and tear of tyres.
Unevenness index is a measure of unevenness which is the cumulative
measure of vertical undulations of the pavement surface recorded per unit
horizontal length of the road.
An unevenness index value less than 1500 mm/km is considered as good, a value
less than 2500 mm.km is satisfactory up to speed of 100 kmph and values greater
than 3200 mm/km is considered as uncomfortable even for 55 kmph.
- White roads have good visibility at night, but caused glare during day
time.
- Black roads has no glare during day, but has poor visibility at night
- Concrete roads has better visibility and less glare
It is necessary that the road surface should be visible at night and reflection
of light is the factor that answers it.
The pavement surface should be absolutely impermeable to prevent seepage of
water into the pavement layers.
Further, both the geometry and texture of pavement surface should help in
draining out the water from the surface in less time.
|
