Anti skid layer

[looserfer]

Hi there

Does anyone know what the definition of “ runway with anti skid layer” ? Is it the same at runway grooved?
Kindly J

[lgwpave]

Looserfer,

Not come across that terminology before, but probably refers to a Porous Friction Course.
This is a coarse asphalt mixture that has a much rougher surface texture. In addition the material is basically honeycombed, which allows water to pass through it, rather than run across the surface. this combination provides good friction characteristics, without the need for grooving.
It is noticably more expensive than grooved asphalt surfacing due to more onerous material specifications and laying methods.
It can create its own problems for maintenance with any patch repairs blocking the flow of water. In addition, rubber deposits from tyres tend to block the pores and are harder to remove than from grooved asphalt.
Used to be quite widespred 30-40 years ago, but nowadays I've only seen it where lighter, high speed landings are more likely (ie. military airfields).